diff --git a/.github/workflows/common-test.yml b/.github/workflows/common-test.yml
index 48202802..10030de5 100644
--- a/.github/workflows/common-test.yml
+++ b/.github/workflows/common-test.yml
@@ -37,7 +37,9 @@ jobs:
           node-version: ${{ env.node_version }}
           registry-url: 'https://registry.npmjs.org'
       - name: Install dependencies
-        run: npm ci
+        run: |
+          node prepareForTest.js cdk-basic
+          npm i
       - name: Download build artifact
         uses: actions/download-artifact@v4
         if: ${{ inputs.mode == 'build' }}
@@ -84,7 +86,9 @@ jobs:
           node-version: ${{ env.node_version }}
           registry-url: 'https://registry.npmjs.org'
       - name: Install dependencies
-        run: npm ci
+        run: |
+          node prepareForTest.js cdk-esm
+          npm i
       - name: Download build artifact
         uses: actions/download-artifact@v4
         if: ${{ inputs.mode == 'build' }}
@@ -131,7 +135,9 @@ jobs:
           node-version: ${{ env.node_version }}
           registry-url: 'https://registry.npmjs.org'
       - name: Install dependencies
-        run: npm ci
+        run: |
+          node prepareForTest.js sls-basic
+          npm i
       - name: Download build artifact
         uses: actions/download-artifact@v4
         if: ${{ inputs.mode == 'build' }}
@@ -179,7 +185,9 @@ jobs:
           node-version: ${{ env.node_version }}
           registry-url: 'https://registry.npmjs.org'
       - name: Install dependencies
-        run: npm ci
+        run: |
+          node prepareForTest.js sls-esbuild-cjs
+          npm i
       - name: Download build artifact
         uses: actions/download-artifact@v4
         if: ${{ inputs.mode == 'build' }}
@@ -227,7 +235,9 @@ jobs:
           node-version: ${{ env.node_version }}
           registry-url: 'https://registry.npmjs.org'
       - name: Install dependencies
-        run: npm ci
+        run: |
+          node prepareForTest.js sls-esbuild-esm
+          npm i
       - name: Download build artifact
         uses: actions/download-artifact@v4
         if: ${{ inputs.mode == 'build' }}
@@ -263,6 +273,156 @@ jobs:
       - name: Test - observability mode
         run: OBSERVABLE_MODE=true npx vitest --retry 1 test/sls-esbuild-esm.test.ts
 
+  test-osls-basic:
+    runs-on: ubuntu-latest
+    concurrency:
+      group: test-osls-basic
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ env.node_version }}
+          registry-url: 'https://registry.npmjs.org'
+      - name: Install dependencies
+        run: |
+          node prepareForTest.js osls-basic
+          npm i
+      - name: Download build artifact
+        uses: actions/download-artifact@v4
+        if: ${{ inputs.mode == 'build' }}
+        with:
+          name: dist
+          path: dist
+      - name: Install lambda-live-debugger globally
+        if: ${{ inputs.mode == 'global' }}
+        run: |
+          npm i lambda-live-debugger -g
+          npm i osls@3.41.0 -g
+        working-directory: test
+      - name: Install lambda-live-debugger locally
+        if: ${{ inputs.mode == 'local' }}
+        run: |
+          npm i lambda-live-debugger
+        working-directory: test
+      - name: Configure AWS Credentials
+        uses: aws-actions/configure-aws-credentials@v4
+        with:
+          aws-region: eu-west-1
+          role-to-assume: ${{ secrets.AWS_ROLE }}
+          role-session-name: GitHubActions
+      - name: Destroy
+        run: npm run destroy
+        working-directory: test/osls-basic
+        continue-on-error: true
+      - name: Deploy
+        run: npm run deploy
+        working-directory: test/osls-basic
+      - name: Test
+        run: npx vitest --retry 1 test/osls-basic.test.ts
+      - name: Test - observability mode
+        run: OBSERVABLE_MODE=true npx vitest --retry 1 test/osls-basic.test.ts
+
+  test-osls-esbuild-cjs:
+    runs-on: ubuntu-latest
+    concurrency:
+      group: test-osls-esbuild-cjs
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ env.node_version }}
+          registry-url: 'https://registry.npmjs.org'
+      - name: Install dependencies
+        run: |
+          node prepareForTest.js osls-esbuild-cjs
+          npm i
+      - name: Download build artifact
+        uses: actions/download-artifact@v4
+        if: ${{ inputs.mode == 'build' }}
+        with:
+          name: dist
+          path: dist
+      - name: Install lambda-live-debugger globally
+        if: ${{ inputs.mode == 'global' }}
+        run: |
+          npm i lambda-live-debugger -g
+          npm i osls@3.41.0 -g
+        working-directory: test
+      - name: Install lambda-live-debugger locally
+        if: ${{ inputs.mode == 'local' }}
+        run: |
+          npm i lambda-live-debugger
+        working-directory: test
+      - name: Configure AWS Credentials
+        uses: aws-actions/configure-aws-credentials@v4
+        with:
+          aws-region: eu-west-1
+          role-to-assume: ${{ secrets.AWS_ROLE }}
+          role-session-name: GitHubActions
+      - name: Destroy
+        run: npm run destroy
+        working-directory: test/osls-esbuild-cjs
+        continue-on-error: true
+      - name: Deploy
+        run: npm run deploy
+        working-directory: test/osls-esbuild-cjs
+      - name: Test
+        run: npx vitest --retry 1 test/osls-esbuild-cjs.test.ts
+      - name: Test - observability mode
+        run: OBSERVABLE_MODE=true npx vitest --retry 1 test/osls-esbuild-cjs.test.ts
+
+  test-osls-esbuild-esm:
+    runs-on: ubuntu-latest
+    concurrency:
+      group: test-osls-esbuild-esm
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ env.node_version }}
+          registry-url: 'https://registry.npmjs.org'
+      - name: Install dependencies
+        run: |
+          node prepareForTest.js osls-esbuild-esm
+          npm i
+      - name: Download build artifact
+        uses: actions/download-artifact@v4
+        if: ${{ inputs.mode == 'build' }}
+        with:
+          name: dist
+          path: dist
+      - name: Install lambda-live-debugger globally
+        if: ${{ inputs.mode == 'global' }}
+        run: |
+          npm i lambda-live-debugger -g
+          npm i osls@3.41.0 -g
+        working-directory: test
+      - name: Install lambda-live-debugger locally
+        if: ${{ inputs.mode == 'local' }}
+        run: |
+          npm i lambda-live-debugger
+        working-directory: test
+      - name: Configure AWS Credentials
+        uses: aws-actions/configure-aws-credentials@v4
+        with:
+          aws-region: eu-west-1
+          role-to-assume: ${{ secrets.AWS_ROLE }}
+          role-session-name: GitHubActions
+      - name: Destroy
+        run: npm run destroy
+        working-directory: test/osls-esbuild-esm
+        continue-on-error: true
+      - name: Deploy
+        run: npm run deploy
+        working-directory: test/osls-esbuild-esm
+      - name: Test
+        run: npx vitest --retry 1 test/osls-esbuild-esm.test.ts
+      - name: Test - observability mode
+        run: OBSERVABLE_MODE=true npx vitest --retry 1 test/osls-esbuild-esm.test.ts
+
   test-sam-basic:
     runs-on: ubuntu-latest
     concurrency:
@@ -279,7 +439,9 @@ jobs:
           node-version: ${{ env.node_version }}
           registry-url: 'https://registry.npmjs.org'
       - name: Install dependencies
-        run: npm ci
+        run: |
+          node prepareForTest.js sam-basic
+          npm i
       - name: Download build artifact
         uses: actions/download-artifact@v4
         if: ${{ inputs.mode == 'build' }}
@@ -330,7 +492,9 @@ jobs:
           node-version: ${{ env.node_version }}
           registry-url: 'https://registry.npmjs.org'
       - name: Install dependencies
-        run: npm ci
+        run: |
+          node prepareForTest.js sam-alt
+          npm i
       - name: Download build artifact
         uses: actions/download-artifact@v4
         if: ${{ inputs.mode == 'build' }}
@@ -377,7 +541,9 @@ jobs:
           node-version: ${{ env.node_version }}
           registry-url: 'https://registry.npmjs.org'
       - name: Install dependencies
-        run: npm ci
+        run: |
+          node prepareForTest.js terraform-basic
+          npm i
       - name: Download build artifact
         uses: actions/download-artifact@v4
         if: ${{ inputs.mode == 'build' }}
diff --git a/.vscode/launch.json b/.vscode/launch.json
index 5bcfd200..f853065e 100755
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -130,6 +130,66 @@
       "type": "node",
       "cwd": "${workspaceRoot}/test/sls-esbuild-esm"
     },
+    {
+      "name": "LLDebugger - OSLS basic",
+      "program": "${workspaceRoot}/node_modules/tsx/dist/cli.mjs",
+      "args": ["../../src/lldebugger.ts", "--stage=test"],
+      "request": "launch",
+      "skipFiles": ["<node_internals>/**"],
+      "console": "integratedTerminal",
+      "type": "node",
+      "cwd": "${workspaceRoot}/test/osls-basic"
+    },
+    {
+      "name": "LLDebugger - OSLS basic - observability",
+      "program": "${workspaceRoot}/node_modules/tsx/dist/cli.mjs",
+      "args": ["../../src/lldebugger.ts", "--stage=test", "-o"],
+      "request": "launch",
+      "skipFiles": ["<node_internals>/**"],
+      "console": "integratedTerminal",
+      "type": "node",
+      "cwd": "${workspaceRoot}/test/osls-basic"
+    },
+    {
+      "name": "LLDebugger - OSLS EsBuild CJS",
+      "program": "${workspaceRoot}/node_modules/tsx/dist/cli.mjs",
+      "args": ["../../src/lldebugger.ts"],
+      "request": "launch",
+      "skipFiles": ["<node_internals>/**"],
+      "console": "integratedTerminal",
+      "type": "node",
+      "cwd": "${workspaceRoot}/test/osls-esbuild-cjs"
+    },
+    {
+      "name": "LLDebugger - OSLS EsBuild CJS - observability",
+      "program": "${workspaceRoot}/node_modules/tsx/dist/cli.mjs",
+      "args": ["../../src/lldebugger.ts", "-o"],
+      "request": "launch",
+      "skipFiles": ["<node_internals>/**"],
+      "console": "integratedTerminal",
+      "type": "node",
+      "cwd": "${workspaceRoot}/test/osls-esbuild-cjs"
+    },
+    {
+      "name": "LLDebugger - OSLS EsBuild ESM",
+      "program": "${workspaceRoot}/node_modules/tsx/dist/cli.mjs",
+      "args": ["../../src/lldebugger.ts"],
+      "request": "launch",
+      "skipFiles": ["<node_internals>/**"],
+      "console": "integratedTerminal",
+      "type": "node",
+      "cwd": "${workspaceRoot}/test/osls-esbuild-esm"
+    },
+    {
+      "name": "LLDebugger - OSLS EsBuild ESM - observability",
+      "program": "${workspaceRoot}/node_modules/tsx/dist/cli.mjs",
+      "args": ["../../src/lldebugger.ts", "-o"],
+      "request": "launch",
+      "skipFiles": ["<node_internals>/**"],
+      "console": "integratedTerminal",
+      "type": "node",
+      "cwd": "${workspaceRoot}/test/osls-esbuild-esm"
+    },
     {
       "name": "LLDebugger - SAM basic",
       "program": "${workspaceRoot}/node_modules/tsx/dist/cli.mjs",
diff --git a/README.md b/README.md
index d4edadd5..d7021c06 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ This tool offers similar functionality to [SST](https://sst.dev/) and [Serverles
 It supports the following frameworks:
 
 - AWS CDK v2
-- Serverless Framework v3 (SLS)
+- Serverless Framework v3 (SLS) and [`osls` fork](https://github.com/oss-serverless/serverless)
 - AWS Serverless Application Model (SAM)
 - Terraform
 - Any other framework or setup by implementing a simple function in TypeScript
diff --git a/package-lock.json b/package-lock.json
index 7f005770..ed3cbafe 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -35,6 +35,10 @@
         "test/cdk-config",
         "test/sls-basic",
         "test/sls-esbuild",
+        "test/sls-esbuild-cjs",
+        "test/osls-basic",
+        "test/osls-esbuild",
+        "test/osls-esbuild-cjs",
         "test/sam-basic",
         "test/sam-alt",
         "test/terraform-basic"
@@ -78,6 +82,7 @@
         "eslint-config-prettier": "^9.1.0",
         "globals": "^15.9.0",
         "husky": "^9.1.4",
+        "osls": "^3.41.0",
         "prettier": "^3.3.3",
         "semantic-release": "^23.0.8",
         "serverless": "^3.38.0",
@@ -3436,21 +3441,6 @@
         "node": ">=10"
       }
     },
-    "node_modules/@serverless/dashboard-plugin/node_modules/is-docker": {
-      "version": "2.2.1",
-      "resolved": "https://registry.npmjs.org/is-docker/-/is-docker-2.2.1.tgz",
-      "integrity": "sha512-F+i2BKsFrH66iaUFc0woD8sLy8getkwTwtOBjvs56Cx4CgJDeKQeqfz8wAYiSb8JOprWhHH5p77PbmYCvvUuXQ==",
-      "dev": true,
-      "bin": {
-        "is-docker": "cli.js"
-      },
-      "engines": {
-        "node": ">=8"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/sindresorhus"
-      }
-    },
     "node_modules/@serverless/dashboard-plugin/node_modules/is-wsl": {
       "version": "2.2.0",
       "resolved": "https://registry.npmjs.org/is-wsl/-/is-wsl-2.2.0.tgz",
@@ -9907,6 +9897,21 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/is-docker": {
+      "version": "2.2.1",
+      "resolved": "https://registry.npmjs.org/is-docker/-/is-docker-2.2.1.tgz",
+      "integrity": "sha512-F+i2BKsFrH66iaUFc0woD8sLy8getkwTwtOBjvs56Cx4CgJDeKQeqfz8wAYiSb8JOprWhHH5p77PbmYCvvUuXQ==",
+      "dev": true,
+      "bin": {
+        "is-docker": "cli.js"
+      },
+      "engines": {
+        "node": ">=8"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
     "node_modules/is-extglob": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/is-extglob/-/is-extglob-2.1.1.tgz",
@@ -13990,21 +13995,6 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/open/node_modules/is-docker": {
-      "version": "2.2.1",
-      "resolved": "https://registry.npmjs.org/is-docker/-/is-docker-2.2.1.tgz",
-      "integrity": "sha512-F+i2BKsFrH66iaUFc0woD8sLy8getkwTwtOBjvs56Cx4CgJDeKQeqfz8wAYiSb8JOprWhHH5p77PbmYCvvUuXQ==",
-      "dev": true,
-      "bin": {
-        "is-docker": "cli.js"
-      },
-      "engines": {
-        "node": ">=8"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/sindresorhus"
-      }
-    },
     "node_modules/open/node_modules/is-wsl": {
       "version": "2.2.0",
       "resolved": "https://registry.npmjs.org/is-wsl/-/is-wsl-2.2.0.tgz",
@@ -14094,6 +14084,228 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/osls": {
+      "version": "3.41.0",
+      "resolved": "https://registry.npmjs.org/osls/-/osls-3.41.0.tgz",
+      "integrity": "sha512-GcrMSRYZFLuk60/pYPoF6bSwkLKZw5Fd8Cc+KTYWIDj8GmgY8V5Cb1YJgxJoYO6IbZgxzwXAcozE/MXd5o8wnA==",
+      "dev": true,
+      "dependencies": {
+        "@aws-sdk/client-api-gateway": "^3.588.0",
+        "@aws-sdk/client-cognito-identity-provider": "^3.588.0",
+        "@aws-sdk/client-eventbridge": "^3.588.0",
+        "@aws-sdk/client-iam": "^3.588.0",
+        "@aws-sdk/client-lambda": "^3.588.0",
+        "@aws-sdk/client-s3": "^3.588.0",
+        "@serverless/utils": "^6.13.1",
+        "ajv": "^8.12.0",
+        "ajv-formats": "^2.1.1",
+        "archiver": "^5.3.1",
+        "aws-sdk": "^2.1404.0",
+        "bluebird": "^3.7.2",
+        "cachedir": "^2.3.0",
+        "chalk": "^4.1.2",
+        "child-process-ext": "^2.1.1",
+        "ci-info": "^3.9.0",
+        "cli-progress-footer": "^2.3.2",
+        "d": "^1.0.1",
+        "dayjs": "^1.11.8",
+        "decompress": "^4.2.1",
+        "dotenv": "^16.3.1",
+        "dotenv-expand": "^10.0.0",
+        "essentials": "^1.2.0",
+        "ext": "^1.7.0",
+        "fastest-levenshtein": "^1.0.16",
+        "filesize": "^10.0.7",
+        "fs-extra": "^10.1.0",
+        "get-stdin": "^8.0.0",
+        "globby": "^11.1.0",
+        "graceful-fs": "^4.2.11",
+        "https-proxy-agent": "^5.0.1",
+        "is-docker": "^2.2.1",
+        "js-yaml": "^4.1.0",
+        "json-cycle": "^1.5.0",
+        "json-refs": "^3.0.15",
+        "lodash": "^4.17.21",
+        "memoizee": "^0.4.15",
+        "micromatch": "^4.0.5",
+        "node-fetch": "^2.6.11",
+        "object-hash": "^3.0.0",
+        "open": "^8.4.2",
+        "process-utils": "^4.0.0",
+        "promise-queue": "^2.2.5",
+        "require-from-string": "^2.0.2",
+        "semver": "^7.5.3",
+        "signal-exit": "^3.0.7",
+        "strip-ansi": "^6.0.1",
+        "supports-color": "^8.1.1",
+        "timers-ext": "^0.1.7",
+        "type": "^2.7.2",
+        "untildify": "^4.0.0",
+        "uuid": "^9.0.0",
+        "ws": "^7.5.9",
+        "yaml-ast-parser": "0.0.43"
+      },
+      "bin": {
+        "serverless": "bin/serverless.js",
+        "sls": "bin/serverless.js"
+      },
+      "engines": {
+        "node": ">=12.0"
+      }
+    },
+    "node_modules/osls-basic": {
+      "resolved": "test/osls-basic",
+      "link": true
+    },
+    "node_modules/osls-esbuild": {
+      "resolved": "test/osls-esbuild-cjs",
+      "link": true
+    },
+    "node_modules/osls/node_modules/agent-base": {
+      "version": "6.0.2",
+      "resolved": "https://registry.npmjs.org/agent-base/-/agent-base-6.0.2.tgz",
+      "integrity": "sha512-RZNwNclF7+MS/8bDg70amg32dyeZGZxiDuQmZxKLAlQjr3jGyLx+4Kkk58UO7D2QdgFIQCovuSuZESne6RG6XQ==",
+      "dev": true,
+      "dependencies": {
+        "debug": "4"
+      },
+      "engines": {
+        "node": ">= 6.0.0"
+      }
+    },
+    "node_modules/osls/node_modules/ajv": {
+      "version": "8.17.1",
+      "resolved": "https://registry.npmjs.org/ajv/-/ajv-8.17.1.tgz",
+      "integrity": "sha512-B/gBuNg5SiMTrPkC+A2+cW0RszwxYmn6VYxB/inlBStS5nx6xHIt/ehKRhIMhqusl7a8LjQoZnjCs5vhwxOQ1g==",
+      "dev": true,
+      "dependencies": {
+        "fast-deep-equal": "^3.1.3",
+        "fast-uri": "^3.0.1",
+        "json-schema-traverse": "^1.0.0",
+        "require-from-string": "^2.0.2"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/epoberezkin"
+      }
+    },
+    "node_modules/osls/node_modules/chalk": {
+      "version": "4.1.2",
+      "resolved": "https://registry.npmjs.org/chalk/-/chalk-4.1.2.tgz",
+      "integrity": "sha512-oKnbhFyRIXpUuez8iBMmyEa4nbj4IOQyuhc/wy9kY7/WVPcwIO9VA668Pu8RkO7+0G76SLROeyw9CpQ061i4mA==",
+      "dev": true,
+      "dependencies": {
+        "ansi-styles": "^4.1.0",
+        "supports-color": "^7.1.0"
+      },
+      "engines": {
+        "node": ">=10"
+      },
+      "funding": {
+        "url": "https://github.com/chalk/chalk?sponsor=1"
+      }
+    },
+    "node_modules/osls/node_modules/chalk/node_modules/supports-color": {
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-7.2.0.tgz",
+      "integrity": "sha512-qpCAvRl9stuOHveKsn7HncJRvv501qIacKzQlO/+Lwxc9+0q2wLyv4Dfvt80/DPn2pqOBsJdDiogXGR9+OvwRw==",
+      "dev": true,
+      "dependencies": {
+        "has-flag": "^4.0.0"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/osls/node_modules/fs-extra": {
+      "version": "10.1.0",
+      "resolved": "https://registry.npmjs.org/fs-extra/-/fs-extra-10.1.0.tgz",
+      "integrity": "sha512-oRXApq54ETRj4eMiFzGnHWGy+zo5raudjuxN0b8H7s/RU2oW0Wvsx9O0ACRN/kRq9E8Vu/ReskGB5o3ji+FzHQ==",
+      "dev": true,
+      "dependencies": {
+        "graceful-fs": "^4.2.0",
+        "jsonfile": "^6.0.1",
+        "universalify": "^2.0.0"
+      },
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/osls/node_modules/globby": {
+      "version": "11.1.0",
+      "resolved": "https://registry.npmjs.org/globby/-/globby-11.1.0.tgz",
+      "integrity": "sha512-jhIXaOzy1sb8IyocaruWSn1TjmnBVs8Ayhcy83rmxNJ8q2uWKCAj3CnJY+KpGSXCueAPc0i05kVvVKtP1t9S3g==",
+      "dev": true,
+      "dependencies": {
+        "array-union": "^2.1.0",
+        "dir-glob": "^3.0.1",
+        "fast-glob": "^3.2.9",
+        "ignore": "^5.2.0",
+        "merge2": "^1.4.1",
+        "slash": "^3.0.0"
+      },
+      "engines": {
+        "node": ">=10"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
+    "node_modules/osls/node_modules/https-proxy-agent": {
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/https-proxy-agent/-/https-proxy-agent-5.0.1.tgz",
+      "integrity": "sha512-dFcAjpTQFgoLMzC2VwU+C/CbS7uRL0lWmxDITmqm7C+7F0Odmj6s9l6alZc6AELXhrnggM2CeWSXHGOdX2YtwA==",
+      "dev": true,
+      "dependencies": {
+        "agent-base": "6",
+        "debug": "4"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/osls/node_modules/json-schema-traverse": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-1.0.0.tgz",
+      "integrity": "sha512-NM8/P9n3XjXhIZn1lLhkFaACTOURQXjWhV4BA/RnOv8xvgqtqpAX9IO4mRQxSx1Rlo4tqzeqb0sOlruaOy3dug==",
+      "dev": true
+    },
+    "node_modules/osls/node_modules/signal-exit": {
+      "version": "3.0.7",
+      "resolved": "https://registry.npmjs.org/signal-exit/-/signal-exit-3.0.7.tgz",
+      "integrity": "sha512-wnD2ZE+l+SPC/uoS0vXeE9L1+0wuaMqKlfz9AMUo38JsyLSBWSFcHR1Rri62LZc12vLr1gb3jl7iwQhgwpAbGQ==",
+      "dev": true
+    },
+    "node_modules/osls/node_modules/slash": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/slash/-/slash-3.0.0.tgz",
+      "integrity": "sha512-g9Q1haeby36OSStwb4ntCGGGaKsaVSjQ68fBxoQcutl5fS1vuY18H3wSt3jFyFtrkx+Kz0V1G85A4MyAdDMi2Q==",
+      "dev": true,
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/osls/node_modules/ws": {
+      "version": "7.5.10",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-7.5.10.tgz",
+      "integrity": "sha512-+dbF1tHwZpXcbOJdVOkzLDxZP1ailvSxM6ZweXTegylPny803bFhA+vqBYw4s31NSAk4S2Qz+AKXK9a4wkdjcQ==",
+      "dev": true,
+      "engines": {
+        "node": ">=8.3.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": "^5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/p-cancelable": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/p-cancelable/-/p-cancelable-2.1.1.tgz",
@@ -15796,21 +16008,6 @@
         "node": ">= 6"
       }
     },
-    "node_modules/serverless/node_modules/is-docker": {
-      "version": "2.2.1",
-      "resolved": "https://registry.npmjs.org/is-docker/-/is-docker-2.2.1.tgz",
-      "integrity": "sha512-F+i2BKsFrH66iaUFc0woD8sLy8getkwTwtOBjvs56Cx4CgJDeKQeqfz8wAYiSb8JOprWhHH5p77PbmYCvvUuXQ==",
-      "dev": true,
-      "bin": {
-        "is-docker": "cli.js"
-      },
-      "engines": {
-        "node": ">=8"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/sindresorhus"
-      }
-    },
     "node_modules/serverless/node_modules/json-schema-traverse": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-1.0.0.tgz",
@@ -16083,6 +16280,10 @@
       "resolved": "test/sls-basic",
       "link": true
     },
+    "node_modules/sls-esbuild": {
+      "resolved": "test/sls-esbuild-cjs",
+      "link": true
+    },
     "node_modules/sort-keys": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/sort-keys/-/sort-keys-1.1.2.tgz",
@@ -18569,13 +18770,10 @@
       "license": "ISC",
       "dependencies": {
         "@aws-sdk/client-iam": "^3.577.0",
-        "@tsconfig/node20": "^20.1.4",
-        "esbuild": "^0.20.1"
+        "@tsconfig/node20": "^20.1.4"
       },
       "devDependencies": {
         "@aws-sdk/client-lambda": "^3.577.0",
-        "serverless": "^3.38.0",
-        "serverless-esbuild": "^1.52.1",
         "typescript": "~5.4.3",
         "vitest": "^2.0.4"
       }
@@ -18656,6 +18854,29 @@
       "integrity": "sha512-JlCMO+ehdEIKqlFxk6IfVoAUVmgz7cU7zD/h9XZ0qzeosSHmUJVOzSQvvYSYWXkFXC+IfLKSIffhv0sVZup6pA==",
       "dev": true
     },
+    "test/osls-basic": {
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "@aws-sdk/client-sts": "^3.577.0"
+      },
+      "devDependencies": {
+        "osls": "^3.41.0"
+      }
+    },
+    "test/osls-esbuild-cjs": {
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "@aws-sdk/client-sts": "^3.577.0"
+      },
+      "devDependencies": {
+        "@tsconfig/node20": "^20.1.4",
+        "esbuild": "^0.20.2",
+        "osls": "^3.41.0",
+        "serverless-esbuild": "^1.52.1"
+      }
+    },
     "test/sam-alt": {
       "version": "0.0.1",
       "dependencies": {
@@ -18686,6 +18907,20 @@
         "serverless": "^3.38.0"
       }
     },
+    "test/sls-esbuild-cjs": {
+      "name": "sls-esbuild",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "@aws-sdk/client-sts": "^3.577.0"
+      },
+      "devDependencies": {
+        "@tsconfig/node20": "^20.1.4",
+        "esbuild": "^0.20.2",
+        "serverless": "^3.38.0",
+        "serverless-esbuild": "^1.52.1"
+      }
+    },
     "test/terraform-basic": {
       "version": "1.0.0",
       "license": "ISC",
diff --git a/package.json b/package.json
index b42e0728..336a56b0 100755
--- a/package.json
+++ b/package.json
@@ -60,6 +60,12 @@
     "test-sls-esbuild-cjs-observable": "npm run build && RUN_TEST_FROM_CLI=true OBSERVABLE_MODE=true vitest run test/sls-esbuild-cjs.test.ts",
     "test-sls-esbuild-esm": "npm run build && RUN_TEST_FROM_CLI=true vitest run test/sls-esbuild-esm.test.ts",
     "test-sls-esbuild-esm-observable": "npm run build && RUN_TEST_FROM_CLI=true OBSERVABLE_MODE=true vitest run test/sls-esbuild-esm.test.ts",
+    "test-osls-basic": "npm run build && RUN_TEST_FROM_CLI=true vitest run test/osls-basic.test.ts",
+    "test-osls-basic-observable": "npm run build && RUN_TEST_FROM_CLI=true OBSERVABLE_MODE=true vitest run test/osls-basic.test.ts",
+    "test-osls-esbuild-cjs": "npm run build && RUN_TEST_FROM_CLI=true vitest run test/osls-esbuild-cjs.test.ts",
+    "test-osls-esbuild-cjs-observable": "npm run build && RUN_TEST_FROM_CLI=true OBSERVABLE_MODE=true vitest run test/osls-esbuild-cjs.test.ts",
+    "test-osls-esbuild-esm": "npm run build && RUN_TEST_FROM_CLI=true vitest run test/osls-esbuild-esm.test.ts",
+    "test-osls-esbuild-esm-observable": "npm run build && RUN_TEST_FROM_CLI=true OBSERVABLE_MODE=true vitest run test/osls-esbuild-esm.test.ts",
     "test-sam-basic": "npm run build && RUN_TEST_FROM_CLI=true vitest run test/sam-basic.test.ts",
     "test-sam-basic-observable": "npm run build && RUN_TEST_FROM_CLI=true OBSERVABLE_MODE=true vitest run test/sam-basic.test.ts",
     "test-sam-alt": "npm run build && RUN_TEST_FROM_CLI=true vitest run test/sam-alt.test.ts",
@@ -89,6 +95,7 @@
     "prettier": "^3.3.3",
     "semantic-release": "^23.0.8",
     "serverless": "^3.38.0",
+    "osls": "^3.41.0",
     "serverless-esbuild": "^1.52.1",
     "tsx": "^4.7.1",
     "typescript-eslint": "^8.0.0",
@@ -141,6 +148,10 @@
     "test/cdk-config",
     "test/sls-basic",
     "test/sls-esbuild",
+    "test/sls-esbuild-cjs",
+    "test/osls-basic",
+    "test/osls-esbuild",
+    "test/osls-esbuild-cjs",
     "test/sam-basic",
     "test/sam-alt",
     "test/terraform-basic"
diff --git a/prepareForTest.js b/prepareForTest.js
new file mode 100644
index 00000000..4a1c84ed
--- /dev/null
+++ b/prepareForTest.js
@@ -0,0 +1,33 @@
+import { readFile, writeFile } from 'fs/promises';
+import { argv } from 'process';
+
+/**
+ * Prepare the package.json file for testing.
+ * Remove everything that is not needed for testing.
+ * @param {*} testCase
+ */
+async function modifyPackageJson(testCase) {
+  const filePath = 'package.json';
+
+  const data = await readFile(filePath, 'utf-8');
+  const packageJson = JSON.parse(data);
+
+  // Delete scripts and devDependencies nodes
+  delete packageJson.scripts;
+  delete packageJson.devDependencies;
+
+  // Replace workspaces node with the test and the test case workspaces
+  // With this all the necessary npm packages will be installed
+  packageJson.workspaces = ['test', `test/${testCase}`];
+
+  await writeFile(filePath, JSON.stringify(packageJson, null, 2), 'utf-8');
+  console.log(`Modified ${filePath} successfully!`);
+}
+
+const [testCase] = argv.slice(2);
+if (!testCase) {
+  console.error('Usage: node prepareForTest.js <testCase>');
+  process.exit(1);
+}
+
+void modifyPackageJson(testCase).catch(console.error);
diff --git a/src/frameworks/slsFramework.ts b/src/frameworks/slsFramework.ts
index d18c69f0..1d559f77 100755
--- a/src/frameworks/slsFramework.ts
+++ b/src/frameworks/slsFramework.ts
@@ -62,72 +62,38 @@ export class SlsFramework implements IFramework {
     let resolveVariablesMeta: any;
     let sources: any;
     let Serverless: any;
+    let error1: any | undefined;
 
     try {
-      // lazy load modules
-      resolveConfigurationPath = (
-        await import(
-          //@ts-ignore
-          'serverless/lib/cli/resolve-configuration-path.js'
-        )
-      ).default;
-      readConfiguration = (
-        await import(
-          //@ts-ignore
-          'serverless/lib/configuration/read.js'
-        )
-      ).default;
-      resolveVariables = (
-        await import(
-          //@ts-ignore
-          'serverless/lib/configuration/variables/resolve.js'
-        )
-      ).default;
-      resolveVariablesMeta = (
-        await import(
-          //@ts-ignore
-          'serverless/lib/configuration/variables/resolve-meta.js'
-        )
-      ).default;
-      const env = await import(
-        //@ts-ignore
-        'serverless/lib/configuration/variables/sources/env.js'
-      );
-      const file = await import(
-        //@ts-ignore
-        'serverless/lib/configuration/variables/sources/file.js'
-      );
-      const opt = await import(
-        //@ts-ignore
-        'serverless/lib/configuration/variables/sources/opt.js'
-      );
-      const self = await import(
-        //@ts-ignore
-        'serverless/lib/configuration/variables/sources/self.js'
-      );
-      const strToBool = await import(
-        //@ts-ignore
-        'serverless/lib/configuration/variables/sources/str-to-bool.js'
-      );
-      const sls = await import(
-        //@ts-ignores
-        'serverless/lib/configuration/variables/sources/instance-dependent/get-sls.js'
-      );
-
-      sources = {
-        env: env.default,
-        file: file.default,
-        opt: opt.default,
-        self: self.default,
-        strToBool: strToBool.default,
-        sls: sls.default(),
-      };
-
-      Serverless = (await import('serverless')).default;
-    } catch (error: any) {
-      Logger.error('Error loading serverless modules', error);
+      try {
+        const frameworkFunctions = await loadFramework('serverless');
+        resolveConfigurationPath = frameworkFunctions.resolveConfigurationPath;
+        readConfiguration = frameworkFunctions.readConfiguration;
+        resolveVariables = frameworkFunctions.resolveVariables;
+        resolveVariablesMeta = frameworkFunctions.resolveVariablesMeta;
+        sources = frameworkFunctions.sources;
+        Serverless = frameworkFunctions.Serverless;
+
+        Logger.verbose(`[SLS] Npm module 'serverless' loaded`);
+      } catch (error: any) {
+        Logger.verbose(`[SLS] Failed to load npm module 'serverless'`, error);
+
+        error1 = error;
+        const frameworkFunctions = await loadFramework('osls');
+        resolveConfigurationPath = frameworkFunctions.resolveConfigurationPath;
+        readConfiguration = frameworkFunctions.readConfiguration;
+        resolveVariables = frameworkFunctions.resolveVariables;
+        resolveVariablesMeta = frameworkFunctions.resolveVariablesMeta;
+        sources = frameworkFunctions.sources;
+        Serverless = frameworkFunctions.Serverless;
+
+        Logger.verbose(`[SLS] Npm module 'osls' loaded`);
+      }
+    } catch (error2: any) {
+      const error = error1 ?? error2;
+      Logger.error('Error loading serverless (or osls) module', error);
       Logger.log(
-        'If you are running Lambda Live Debugger from a global installation, install Serverless Framework globally as well. If you are using monorepo, install Serverless Framework also in the project root folder.',
+        'If you are running Lambda Live Debugger from a global installation, install Serverless Framework globally as well. If you are using monorepo, install Serverless Framework also in the project root folder. The fork of Serverless Framework https://github.com/oss-serverless/serverless is also supported.',
       );
       throw new Error(`Error loading serverless modules. ${error.message}`, {
         cause: error,
@@ -315,3 +281,73 @@ export class SlsFramework implements IFramework {
 }
 
 export const slsFramework = new SlsFramework();
+async function loadFramework(npmName: string) {
+  // lazy load modules
+  const resolveConfigurationPath = (
+    await import(
+      //@ts-ignore
+      `${npmName}/lib/cli/resolve-configuration-path.js`
+    )
+  ).default;
+  const readConfiguration = (
+    await import(
+      //@ts-ignore
+      `${npmName}/lib/configuration/read.js`
+    )
+  ).default;
+  const resolveVariables = (
+    await import(
+      //@ts-ignore
+      `${npmName}/lib/configuration/variables/resolve.js`
+    )
+  ).default;
+  const resolveVariablesMeta = (
+    await import(
+      //@ts-ignore
+      `${npmName}/lib/configuration/variables/resolve-meta.js`
+    )
+  ).default;
+  const env = await import(
+    //@ts-ignore
+    `${npmName}/lib/configuration/variables/sources/env.js`
+  );
+  const file = await import(
+    //@ts-ignore
+    `${npmName}/lib/configuration/variables/sources/file.js`
+  );
+  const opt = await import(
+    //@ts-ignore
+    `${npmName}/lib/configuration/variables/sources/opt.js`
+  );
+  const self = await import(
+    //@ts-ignore
+    `${npmName}/lib/configuration/variables/sources/self.js`
+  );
+  const strToBool = await import(
+    //@ts-ignore
+    `${npmName}/lib/configuration/variables/sources/str-to-bool.js`
+  );
+  const sls = await import(
+    //@ts-ignores
+    `${npmName}/lib/configuration/variables/sources/instance-dependent/get-sls.js`
+  );
+
+  const sources = {
+    env: env.default,
+    file: file.default,
+    opt: opt.default,
+    self: self.default,
+    strToBool: strToBool.default,
+    sls: sls.default(),
+  };
+
+  const Serverless = (await import(npmName)).default;
+  return {
+    resolveConfigurationPath,
+    readConfiguration,
+    resolveVariablesMeta,
+    resolveVariables,
+    sources,
+    Serverless,
+  };
+}
diff --git a/test/cdk-basic/package.json b/test/cdk-basic/package.json
index 50a05a5c..2f141970 100644
--- a/test/cdk-basic/package.json
+++ b/test/cdk-basic/package.json
@@ -7,7 +7,7 @@
   "scripts": {
     "deploy": "cdk deploy --all -c environment=test --require-approval never --outputs-file cdk-outputs.json",
     "build": "cdk synth -c environment=test",
-    "destroy": "cdk destroy  -c environment=test --force"
+    "destroy": "cdk destroy --all -c environment=test --force"
   },
   "devDependencies": {
     "@types/node": "20.11.30",
diff --git a/test/cdk-esm/package.json b/test/cdk-esm/package.json
index 788a5d79..c95455a4 100644
--- a/test/cdk-esm/package.json
+++ b/test/cdk-esm/package.json
@@ -8,7 +8,7 @@
   "scripts": {
     "deploy": "cdk deploy --all -c environment=test --require-approval never --outputs-file cdk-outputs.json",
     "build": "cdk synth -c environment=test",
-    "destroy": "cdk destroy  -c environment=test --force"
+    "destroy": "cdk destroy  --all -c environment=test --force"
   },
   "devDependencies": {
     "@tsconfig/node20": "^20.1.4",
diff --git a/test/osls-basic.test.ts b/test/osls-basic.test.ts
new file mode 100644
index 00000000..60b4f36c
--- /dev/null
+++ b/test/osls-basic.test.ts
@@ -0,0 +1,71 @@
+import { expect, test, describe, beforeAll, afterAll } from 'vitest';
+import { ChildProcess } from 'child_process';
+import { startDebugger } from './utils/startDebugger.js';
+import { expectInfraRemoved } from './utils/expectInfraRemoved.js';
+import { expectInfraDeployed } from './utils/expectInfraDeployed.js';
+import { removeInfra } from './utils/removeInfra.js';
+import { exec } from 'child_process';
+import { promisify } from 'util';
+import { callLambda } from './utils/callLambda.js';
+import { getSamplePayload } from './utils/getSamplePayload.js';
+import { validateLocalResponse } from './utils/validateLocalResponse.js';
+import { getTestProjectFolder } from './utils/getTestProjectFolder.js';
+
+export const execAsync = promisify(exec);
+
+const observableMode = process.env.OBSERVABLE_MODE === 'true';
+
+describe('osls-basic', async () => {
+  const folder = await getTestProjectFolder('osls-basic');
+  let lldProcess: ChildProcess | undefined;
+
+  beforeAll(async () => {
+    if (process.env.CI === 'true' || process.env.RUN_TEST_FROM_CLI === 'true') {
+      lldProcess = await startDebugger(folder, ['--stage=test']);
+    }
+  });
+
+  afterAll(async () => {
+    // stop the debugger
+    lldProcess?.kill();
+  });
+
+  test('check infra', async () => {
+    const lambdaName = 'lls-osls-basic-test-testJsCommonJs';
+    await expectInfraDeployed(lambdaName);
+  });
+
+  test('call Lambda - testJsCommonJs', async () => {
+    const lambdaName = 'lls-osls-basic-test-testJsCommonJs';
+
+    const payload = getSamplePayload(lambdaName);
+    const response = await callLambda(lambdaName, payload);
+
+    expect(response.inputEvent).toEqual(payload);
+    expect(response.runningLocally).toEqual(!observableMode);
+    if (observableMode) {
+      await validateLocalResponse(lambdaName, payload);
+    }
+  });
+
+  test('call Lambda - testJsEsModule', async () => {
+    const lambdaName = 'lls-osls-basic-test-testJsEsModule';
+
+    const payload = getSamplePayload(lambdaName);
+    const response = await callLambda(lambdaName, payload);
+
+    expect(response.inputEvent).toEqual(payload);
+    expect(response.runningLocally).toEqual(!observableMode);
+    if (observableMode) {
+      await validateLocalResponse(lambdaName, payload);
+    }
+  });
+
+  test('remove infra', async () => {
+    if (process.env.CI === 'true' || process.env.RUN_TEST_FROM_CLI === 'true') {
+      await removeInfra(lldProcess, folder, ['--stage=test']);
+      const lambdaName = 'lls-osls-basic-test-testJsCommonJs';
+      await expectInfraRemoved(lambdaName);
+    }
+  });
+});
diff --git a/test/osls-basic/.gitignore b/test/osls-basic/.gitignore
new file mode 100644
index 00000000..2b48c8bd
--- /dev/null
+++ b/test/osls-basic/.gitignore
@@ -0,0 +1,6 @@
+# package directories
+node_modules
+jspm_packages
+
+# Serverless directories
+.serverless
\ No newline at end of file
diff --git a/test/osls-basic/functions1.yml b/test/osls-basic/functions1.yml
new file mode 100644
index 00000000..7226b5a0
--- /dev/null
+++ b/test/osls-basic/functions1.yml
@@ -0,0 +1,2 @@
+testJsEsModule:
+  handler: services/testJsEsModule/lambda.lambdaHandler
diff --git a/test/osls-basic/functions2.yml b/test/osls-basic/functions2.yml
new file mode 100644
index 00000000..52f57d79
--- /dev/null
+++ b/test/osls-basic/functions2.yml
@@ -0,0 +1,2 @@
+testJsCommonJs:
+  handler: services/testJsCommonJs/lambda.lambdaHandler
diff --git a/test/osls-basic/package.json b/test/osls-basic/package.json
new file mode 100644
index 00000000..d2f8a92a
--- /dev/null
+++ b/test/osls-basic/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "osls-basic",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "deploy": "serverless deploy --stage=test",
+    "destroy": "serverless remove --stage=test"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "devDependencies": {
+    "osls": "^3.41.0"
+  },
+  "dependencies": {
+    "@aws-sdk/client-sts": "^3.577.0"
+  }
+}
diff --git a/test/osls-basic/serverless.yml b/test/osls-basic/serverless.yml
new file mode 100644
index 00000000..601cb316
--- /dev/null
+++ b/test/osls-basic/serverless.yml
@@ -0,0 +1,11 @@
+service: lls-osls-basic
+frameworkVersion: '3'
+
+provider:
+  name: aws
+  runtime: nodejs20.x
+  region: eu-west-1
+
+functions:
+  - ${file(./functions1.yml)}
+  - ${file(./functions2.yml)}
diff --git a/test/osls-basic/services/testJsCommonJs/lambda.js b/test/osls-basic/services/testJsCommonJs/lambda.js
new file mode 100755
index 00000000..4e37462d
--- /dev/null
+++ b/test/osls-basic/services/testJsCommonJs/lambda.js
@@ -0,0 +1,40 @@
+const { STSClient, GetCallerIdentityCommand } = require('@aws-sdk/client-sts');
+
+const stsClient = new STSClient({});
+
+const lambdaHandler = async (event, context) => {
+  // Check context
+  const remainingTime = context.getRemainingTimeInMillis();
+  if (remainingTime === undefined) {
+    throw new Error('Remaining time is undefined');
+  }
+
+  // check if SDK works
+  const command = new GetCallerIdentityCommand({});
+  const identity = await stsClient.send(command);
+
+  const response = {
+    inputEvent: event,
+    accountId: identity.Account,
+    runningLocally: process.env.IS_LOCAL === 'true',
+  };
+
+  if (process.env.IS_LOCAL === 'true') {
+    const fs = require('fs');
+    const path = require('path');
+    const filePath = path.join(
+      '..',
+      'local_lambda_responses',
+      `${context.functionName}.json`,
+    );
+
+    fs.writeFileSync(filePath, JSON.stringify(response, null, 2));
+  }
+
+  return response;
+};
+
+// Export the lambda handler if needed, e.g., for unit testing
+module.exports = {
+  lambdaHandler,
+};
diff --git a/test/osls-basic/services/testJsCommonJs/package.json b/test/osls-basic/services/testJsCommonJs/package.json
new file mode 100644
index 00000000..9a7eb492
--- /dev/null
+++ b/test/osls-basic/services/testJsCommonJs/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "sls-basic-test-js-commonjs",
+  "version": "1.0.0",
+  "type": "commonjs",
+  "dependencies": {
+    "@aws-sdk/client-sts": "^3.577.0"
+  }
+}
diff --git a/test/osls-basic/services/testJsEsModule/lambda.js b/test/osls-basic/services/testJsEsModule/lambda.js
new file mode 100755
index 00000000..e3508208
--- /dev/null
+++ b/test/osls-basic/services/testJsEsModule/lambda.js
@@ -0,0 +1,35 @@
+import { STSClient, GetCallerIdentityCommand } from '@aws-sdk/client-sts';
+
+const stsClient = new STSClient({});
+
+export const lambdaHandler = async (event, context) => {
+  // check context
+  const remainingTime = context.getRemainingTimeInMillis();
+  if (remainingTime === undefined) {
+    throw new Error('Remaining time is undefined');
+  }
+
+  // check SDK works
+  const command = new GetCallerIdentityCommand({});
+  const identity = await stsClient.send(command);
+
+  const response = {
+    inputEvent: event,
+    accountId: identity.Account,
+    runningLocally: process.env.IS_LOCAL === 'true',
+  };
+
+  if (process.env.IS_LOCAL === 'true') {
+    const fs = await import('fs');
+    const path = await import('path');
+    const filePath = path.join(
+      '..',
+      'local_lambda_responses',
+      `${context.functionName}.json`,
+    );
+
+    fs.writeFileSync(filePath, JSON.stringify(response, null, 2));
+  }
+
+  return response;
+};
diff --git a/test/osls-basic/services/testJsEsModule/package.json b/test/osls-basic/services/testJsEsModule/package.json
new file mode 100644
index 00000000..97225145
--- /dev/null
+++ b/test/osls-basic/services/testJsEsModule/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "sls-basic-test-js-esmodule",
+  "version": "1.0.0",
+  "type": "module",
+  "dependencies": {
+    "@aws-sdk/client-sts": "^3.577.0"
+  }
+}
diff --git a/test/osls-esbuild-cjs.test.ts b/test/osls-esbuild-cjs.test.ts
new file mode 100644
index 00000000..3bf2cca9
--- /dev/null
+++ b/test/osls-esbuild-cjs.test.ts
@@ -0,0 +1,58 @@
+import { expect, test, describe, beforeAll, afterAll } from 'vitest';
+import { ChildProcess } from 'child_process';
+import { startDebugger } from './utils/startDebugger.js';
+import { expectInfraRemoved } from './utils/expectInfraRemoved.js';
+import { expectInfraDeployed } from './utils/expectInfraDeployed.js';
+import { removeInfra } from './utils/removeInfra.js';
+import { exec } from 'child_process';
+import { promisify } from 'util';
+import { callLambda } from './utils/callLambda.js';
+import { getSamplePayload } from './utils/getSamplePayload.js';
+import { validateLocalResponse } from './utils/validateLocalResponse.js';
+import { getTestProjectFolder } from './utils/getTestProjectFolder.js';
+
+export const execAsync = promisify(exec);
+
+const observableMode = process.env.OBSERVABLE_MODE === 'true';
+
+describe('osls-esbuild-cjs', async () => {
+  const folder = await getTestProjectFolder('osls-esbuild-cjs');
+  let lldProcess: ChildProcess | undefined;
+
+  beforeAll(async () => {
+    if (process.env.CI === 'true' || process.env.RUN_TEST_FROM_CLI === 'true') {
+      lldProcess = await startDebugger(folder);
+    }
+  });
+
+  afterAll(async () => {
+    // stop the debugger
+    lldProcess?.kill();
+  });
+
+  test('check infra', async () => {
+    const lambdaName = 'lls-osls-esbuild-cjs-test-testTsCommonJs';
+    await expectInfraDeployed(lambdaName);
+  });
+
+  test('call Lambda - testTsCommonJs', async () => {
+    const lambdaName = 'lls-osls-esbuild-cjs-test-testTsCommonJs';
+
+    const payload = getSamplePayload(lambdaName);
+    const response = await callLambda(lambdaName, payload);
+
+    expect(response.inputEvent).toEqual(payload);
+    expect(response.runningLocally).toEqual(!observableMode);
+    if (observableMode) {
+      await validateLocalResponse(lambdaName, payload);
+    }
+  });
+
+  test('remove infra', async () => {
+    if (process.env.CI === 'true' || process.env.RUN_TEST_FROM_CLI === 'true') {
+      await removeInfra(lldProcess, folder);
+      const lambdaName = 'lls-osls-esbuild-cjs-test-testTsCommonJs';
+      await expectInfraRemoved(lambdaName);
+    }
+  });
+});
diff --git a/test/osls-esbuild-cjs/.gitignore b/test/osls-esbuild-cjs/.gitignore
new file mode 100644
index 00000000..2b48c8bd
--- /dev/null
+++ b/test/osls-esbuild-cjs/.gitignore
@@ -0,0 +1,6 @@
+# package directories
+node_modules
+jspm_packages
+
+# Serverless directories
+.serverless
\ No newline at end of file
diff --git a/test/osls-esbuild-cjs/package.json b/test/osls-esbuild-cjs/package.json
new file mode 100644
index 00000000..44e909f2
--- /dev/null
+++ b/test/osls-esbuild-cjs/package.json
@@ -0,0 +1,23 @@
+{
+  "name": "osls-esbuild",
+  "version": "1.0.0",
+  "description": "",
+  "type": "module",
+  "main": "index.js",
+  "scripts": {
+    "deploy": "serverless deploy",
+    "destroy": "serverless remove"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "devDependencies": {
+    "esbuild": "^0.20.2",
+    "osls": "^3.41.0",
+    "serverless-esbuild": "^1.52.1",
+    "@tsconfig/node20": "^20.1.4"
+  },
+  "dependencies": {
+    "@aws-sdk/client-sts": "^3.577.0"
+  }
+}
diff --git a/test/osls-esbuild-cjs/serverless.yml b/test/osls-esbuild-cjs/serverless.yml
new file mode 100644
index 00000000..718a6fcf
--- /dev/null
+++ b/test/osls-esbuild-cjs/serverless.yml
@@ -0,0 +1,20 @@
+service: lls-osls-esbuild-cjs
+frameworkVersion: '3'
+
+plugins:
+  - serverless-esbuild
+
+provider:
+  name: aws
+  runtime: nodejs20.x
+  region: eu-west-1
+  stage: test
+
+custom:
+  esbuild:
+    bundle: true
+    minify: false
+
+functions:
+  testTsCommonJs:
+    handler: services/testTsCommonJs/lambda.lambdaHandler
diff --git a/test/osls-esbuild-cjs/services/testTsCommonJs/lambda.ts b/test/osls-esbuild-cjs/services/testTsCommonJs/lambda.ts
new file mode 100755
index 00000000..70bd2e6e
--- /dev/null
+++ b/test/osls-esbuild-cjs/services/testTsCommonJs/lambda.ts
@@ -0,0 +1,36 @@
+import { Handler } from 'aws-lambda';
+import { STSClient, GetCallerIdentityCommand } from '@aws-sdk/client-sts';
+
+const stsClient = new STSClient({});
+
+export const lambdaHandler: Handler = async (event, context) => {
+  // check context
+  const remainingTime = context.getRemainingTimeInMillis();
+  if (remainingTime === undefined) {
+    throw new Error('Remaining time is undefined');
+  }
+
+  // check SDK works
+  const command = new GetCallerIdentityCommand({});
+  const identity = await stsClient.send(command);
+
+  const response = {
+    inputEvent: event,
+    accountId: identity.Account,
+    runningLocally: process.env.IS_LOCAL === 'true',
+  };
+
+  if (process.env.IS_LOCAL === 'true') {
+    const fs = await import('fs');
+    const path = await import('path');
+    const filePath = path.join(
+      '..',
+      'local_lambda_responses',
+      `${context.functionName}.json`,
+    );
+
+    fs.writeFileSync(filePath, JSON.stringify(response, null, 2));
+  }
+
+  return response;
+};
diff --git a/test/osls-esbuild-cjs/services/testTsCommonJs/package.json b/test/osls-esbuild-cjs/services/testTsCommonJs/package.json
new file mode 100644
index 00000000..df873a2f
--- /dev/null
+++ b/test/osls-esbuild-cjs/services/testTsCommonJs/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "sls-esbuild-test-ts-commonjs",
+  "version": "1.0.0",
+  "type": "commonjs",
+  "dependencies": {
+    "@aws-sdk/client-sts": "^3.577.0"
+  }
+}
diff --git a/test/osls-esbuild-cjs/services/testTsCommonJs/tsconfig.json b/test/osls-esbuild-cjs/services/testTsCommonJs/tsconfig.json
new file mode 100755
index 00000000..f48ef0ec
--- /dev/null
+++ b/test/osls-esbuild-cjs/services/testTsCommonJs/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "extends": "@tsconfig/node20/tsconfig.json",
+  "compilerOptions": {
+    "moduleResolution": "node",
+    "module": "CommonJS"
+  }
+}
diff --git a/test/osls-esbuild-esm.test.ts b/test/osls-esbuild-esm.test.ts
new file mode 100644
index 00000000..5677e63f
--- /dev/null
+++ b/test/osls-esbuild-esm.test.ts
@@ -0,0 +1,58 @@
+import { expect, test, describe, beforeAll, afterAll } from 'vitest';
+import { ChildProcess } from 'child_process';
+import { startDebugger } from './utils/startDebugger.js';
+import { expectInfraRemoved } from './utils/expectInfraRemoved.js';
+import { expectInfraDeployed } from './utils/expectInfraDeployed.js';
+import { removeInfra } from './utils/removeInfra.js';
+import { exec } from 'child_process';
+import { promisify } from 'util';
+import { callLambda } from './utils/callLambda.js';
+import { getSamplePayload } from './utils/getSamplePayload.js';
+import { validateLocalResponse } from './utils/validateLocalResponse.js';
+import { getTestProjectFolder } from './utils/getTestProjectFolder.js';
+
+export const execAsync = promisify(exec);
+
+const observableMode = process.env.OBSERVABLE_MODE === 'true';
+
+describe('osls-esbuild-esm', async () => {
+  const folder = await getTestProjectFolder('osls-esbuild-esm');
+  let lldProcess: ChildProcess | undefined;
+
+  beforeAll(async () => {
+    if (process.env.CI === 'true' || process.env.RUN_TEST_FROM_CLI === 'true') {
+      lldProcess = await startDebugger(folder);
+    }
+  });
+
+  afterAll(async () => {
+    // stop the debugger
+    lldProcess?.kill();
+  });
+
+  test('check infra', async () => {
+    const lambdaName = 'lls-osls-esbuild-esm-test-testTsEsModule';
+    await expectInfraDeployed(lambdaName);
+  });
+
+  test('call Lambda - testTsEsModule', async () => {
+    const lambdaName = 'lls-osls-esbuild-esm-test-testTsEsModule';
+
+    const payload = getSamplePayload(lambdaName);
+    const response = await callLambda(lambdaName, payload);
+
+    expect(response.inputEvent).toEqual(payload);
+    expect(response.runningLocally).toEqual(!observableMode);
+    if (observableMode) {
+      await validateLocalResponse(lambdaName, payload);
+    }
+  });
+
+  test('remove infra', async () => {
+    if (process.env.CI === 'true' || process.env.RUN_TEST_FROM_CLI === 'true') {
+      await removeInfra(lldProcess, folder);
+      const lambdaName = 'lls-osls-esbuild-esm-test-testTsEsModule';
+      await expectInfraRemoved(lambdaName);
+    }
+  });
+});
diff --git a/test/osls-esbuild-esm/.gitignore b/test/osls-esbuild-esm/.gitignore
new file mode 100644
index 00000000..2b48c8bd
--- /dev/null
+++ b/test/osls-esbuild-esm/.gitignore
@@ -0,0 +1,6 @@
+# package directories
+node_modules
+jspm_packages
+
+# Serverless directories
+.serverless
\ No newline at end of file
diff --git a/test/osls-esbuild-esm/package.json b/test/osls-esbuild-esm/package.json
new file mode 100644
index 00000000..5d512fa4
--- /dev/null
+++ b/test/osls-esbuild-esm/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "osls-esbuild",
+  "version": "1.0.0",
+  "description": "",
+  "type": "module",
+  "main": "index.js",
+  "scripts": {
+    "deploy": "serverless deploy",
+    "destroy": "serverless remove"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "devDependencies": {
+    "esbuild": "^0.20.2",
+    "osls": "^3.41.0",
+    "serverless-esbuild": "^1.52.1",
+    "@types/aws-lambda": "^8.10.137"
+  },
+  "dependencies": {
+    "@tsconfig/node20": "^20.1.4",
+    "@aws-sdk/client-sts": "^3.577.0"
+  }
+}
diff --git a/test/osls-esbuild-esm/serverless.yml b/test/osls-esbuild-esm/serverless.yml
new file mode 100644
index 00000000..cd96d6d2
--- /dev/null
+++ b/test/osls-esbuild-esm/serverless.yml
@@ -0,0 +1,24 @@
+service: lls-osls-esbuild-esm
+frameworkVersion: '3'
+
+plugins:
+  - serverless-esbuild
+
+provider:
+  name: aws
+  runtime: nodejs20.x
+  region: eu-west-1
+  stage: test
+
+custom:
+  esbuild:
+    bundle: true
+    minify: true
+    format: esm
+    outputFileExtension: .mjs
+    banner:
+      js: "import { createRequire } from 'module';const require = createRequire(import.meta.url);"
+
+functions:
+  testTsEsModule:
+    handler: services/testTsEsModule/lambda.lambdaHandler
diff --git a/test/osls-esbuild-esm/services/testTsEsModule/lambda.ts b/test/osls-esbuild-esm/services/testTsEsModule/lambda.ts
new file mode 100755
index 00000000..5e17de6c
--- /dev/null
+++ b/test/osls-esbuild-esm/services/testTsEsModule/lambda.ts
@@ -0,0 +1,35 @@
+import { Handler } from 'aws-lambda';
+import { STSClient, GetCallerIdentityCommand } from '@aws-sdk/client-sts';
+
+const stsClient = new STSClient({});
+
+export const lambdaHandler: Handler = async (event, context) => {
+  // check context
+  const remainingTime = context.getRemainingTimeInMillis();
+  if (remainingTime === undefined) {
+    throw new Error('Remaining time is undefined');
+  }
+
+  // check SDK works
+  const command = new GetCallerIdentityCommand({});
+  const identity = await stsClient.send(command);
+
+  const response = {
+    inputEvent: event,
+    accountId: identity.Account,
+    runningLocally: process.env.IS_LOCAL === 'true',
+  };
+
+  if (process.env.IS_LOCAL === 'true') {
+    const fs = await import('fs');
+    const path = await import('path');
+    const filePath = path.join(
+      '..',
+      'local_lambda_responses',
+      `${context.functionName}.json`,
+    );
+    fs.writeFileSync(filePath, JSON.stringify(response, null, 2));
+  }
+
+  return response;
+};
diff --git a/test/osls-esbuild-esm/services/testTsEsModule/package.json b/test/osls-esbuild-esm/services/testTsEsModule/package.json
new file mode 100644
index 00000000..c2b49e2b
--- /dev/null
+++ b/test/osls-esbuild-esm/services/testTsEsModule/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "sls-esbuild-test-ts-esmodule",
+  "version": "1.0.0",
+  "type": "module",
+  "devDependencies": {
+    "@tsconfig/node20": "^20.1.4"
+  },
+  "dependencies": {
+    "@aws-sdk/client-sts": "^3.577.0"
+  }
+}
diff --git a/test/osls-esbuild-esm/services/testTsEsModule/tsconfig.json b/test/osls-esbuild-esm/services/testTsEsModule/tsconfig.json
new file mode 100755
index 00000000..fca5c83e
--- /dev/null
+++ b/test/osls-esbuild-esm/services/testTsEsModule/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "extends": "@tsconfig/node20/tsconfig.json",
+  "compilerOptions": {
+    "module": "esnext",
+    "moduleResolution": "node"
+  }
+}
diff --git a/test/osls-esbuild-esm/tsconfig.json b/test/osls-esbuild-esm/tsconfig.json
new file mode 100755
index 00000000..fca5c83e
--- /dev/null
+++ b/test/osls-esbuild-esm/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "extends": "@tsconfig/node20/tsconfig.json",
+  "compilerOptions": {
+    "module": "esnext",
+    "moduleResolution": "node"
+  }
+}
diff --git a/test/package.json b/test/package.json
index 05695aa1..6683a679 100644
--- a/test/package.json
+++ b/test/package.json
@@ -11,12 +11,9 @@
   "devDependencies": {
     "@aws-sdk/client-lambda": "^3.577.0",
     "vitest": "^2.0.4",
-    "serverless": "^3.38.0",
-    "serverless-esbuild": "^1.52.1",
     "typescript": "~5.4.3"
   },
   "dependencies": {
-    "esbuild": "^0.20.1",
     "@aws-sdk/client-iam": "^3.577.0",
     "@tsconfig/node20": "^20.1.4"
   }