diff --git a/packages/config/src/cached_config.js b/packages/config/src/cached_config.js
deleted file mode 100644
index 4268445f87..0000000000
--- a/packages/config/src/cached_config.js
+++ /dev/null
@@ -1,29 +0,0 @@
-import { promises as fs } from 'fs'
-
-// Performance optimization when @netlify/config caller has already previously
-// called it and cached the result.
-// This is used by the buildbot which:
-//  - first calls @netlify/config since it needs configuration property
-//  - later calls @netlify/build, which runs @netlify/config under the hood
-// This is also used by Netlify CLI.
-export const getCachedConfig = async function ({ cachedConfig, cachedConfigPath, token, api }) {
-  const parsedCachedConfig = await parseCachedConfig(cachedConfig, cachedConfigPath)
-  // The CLI does not print some properties when they are not serializable or
-  // are confidential. Those will be missing from `cachedConfig`. The caller
-  // must supply them again when using `cachedConfig`.
-  return parsedCachedConfig === undefined ? undefined : { token, ...parsedCachedConfig, api }
-}
-
-// `cachedConfig` is a plain object while `cachedConfigPath` is a file path to
-// a JSON file. The former is useful in programmatic usage while the second one
-// is useful in CLI usage, to avoid hitting the OS limits if the configuration
-// file is too big.
-const parseCachedConfig = async function (cachedConfig, cachedConfigPath) {
-  if (cachedConfig !== undefined) {
-    return cachedConfig
-  }
-
-  if (cachedConfigPath !== undefined) {
-    return JSON.parse(await fs.readFile(cachedConfigPath))
-  }
-}
diff --git a/packages/config/src/cached_config.ts b/packages/config/src/cached_config.ts
new file mode 100644
index 0000000000..02ef1d4320
--- /dev/null
+++ b/packages/config/src/cached_config.ts
@@ -0,0 +1,129 @@
+import fs from 'node:fs/promises'
+
+import type { NetlifyAPI } from '@netlify/api'
+import * as z from 'zod'
+
+// TODO: There are likely fields missing here, and many of these fields are probably optional.
+export const SerializedCachedConfigSchema = z.object({
+  accounts: z.array(
+    z.object({
+      id: z.string(),
+      name: z.string(),
+      slug: z.string(),
+      default: z.boolean(),
+      team_logo_url: z.string().nullable(),
+      on_pro_trial: z.boolean(),
+      organization_id: z.string().nullable(),
+      type_name: z.string(),
+      type_slug: z.string(),
+      members_count: z.number(),
+    }),
+  ),
+  branch: z.string(),
+  buildDir: z.string(),
+  config: z.object({
+    build: z.object({
+      edge_functions: z.string().optional(),
+      environment: z.record(
+        z.string(),
+        z.object({
+          sources: z.array(z.string()), // z.array(z.enum(['internal', 'ui', ...])),
+          value: z.string(),
+        }),
+      ),
+      functions: z.string().optional(),
+      publish: z.string(),
+      publishOrigin: z.string(), // z.enum(['config']),
+      processing: z.record(z.string(), z.unknown()),
+      services: z.record(z.string(), z.unknown()),
+      command: z.string(),
+      commandOrigin: z.string(), // z.enum(['config', ...])
+    }),
+    functions: z.record(z.string(), z.record(z.string(), z.unknown())),
+    functionsDirectory: z.string().optional(),
+    functionsDirectoryOrigin: z.string().optional(), // z.enum(['config', 'default', 'default-v1', 'ui', ...]),
+    plugins: z.array(
+      z.object({
+        origin: z.string(), // z.enum(['config', ...])
+        package: z.string(),
+        inputs: z.record(z.string(), z.unknown()),
+      }),
+    ),
+    headers: z.array(z.unknown()),
+    redirects: z.array(z.unknown()),
+  }),
+  configPath: z.string(),
+  context: z.string(), // z.enum(['production', 'deploy-preview', 'branch-deploy', 'dev', 'dev-server']),
+  env: z.record(
+    z.string(),
+    z.object({
+      sources: z.array(z.string()), // z.array(z.enum(['internal', 'ui', ...])),
+      value: z.string(),
+    }),
+  ),
+  integrations: z.array(
+    z.object({
+      author: z.string(),
+      buildPlugin: z.object({
+        origin: z.string(),
+        packageURL: z.string(),
+      }),
+      extension_token: z.string(),
+      has_build: z.boolean(),
+      name: z.string(),
+      slug: z.string(),
+      version: z.string(),
+    }),
+  ),
+  hasApi: z.boolean().optional(),
+  headersPath: z.string(),
+  siteInfo: z.record(z.string(), z.unknown()), // z.object({ id: z.string(), account_id: z.string() }),
+  redirectsPath: z.string(),
+  repositoryRoot: z.string(),
+})
+
+// export type SerializedCachedConfig = z.output<typeof SerializedCachedConfigSchema>
+
+// Performance optimization when @netlify/config caller has already previously
+// called it and cached the result.
+// This is used by the buildbot which:
+//  - first calls @netlify/config since it needs configuration property
+//  - later calls @netlify/build, which runs @netlify/config under the hood
+// This is also used by Netlify CLI.
+export const getCachedConfig = async function ({
+  api,
+  cachedConfig,
+  cachedConfigPath,
+  token,
+}: {
+  api: NetlifyAPI | undefined
+  cachedConfig: unknown
+  cachedConfigPath: string | undefined
+  token: string | undefined
+}): // eslint-disable-next-line @typescript-eslint/no-explicit-any
+Promise<any> {
+  const parsedCachedConfig = await parseCachedConfig(cachedConfig, cachedConfigPath)
+  // The CLI does not print some properties when they are not serializable or
+  // are confidential. Those will be missing from `cachedConfig`. The caller
+  // must supply them again when using `cachedConfig`.
+  return parsedCachedConfig === undefined ? undefined : { token, ...parsedCachedConfig, api }
+}
+
+// `cachedConfig` is a plain object while `cachedConfigPath` is a file path to
+// a JSON file. The former is useful in programmatic usage while the second one
+// is useful in CLI usage, to avoid hitting the OS limits if the configuration
+// file is too big.
+const parseCachedConfig = async function (
+  cachedConfig: unknown,
+  cachedConfigPath: string | undefined,
+): Promise<unknown> {
+  if (cachedConfig !== undefined) {
+    // return cachedConfig
+    return SerializedCachedConfigSchema.parse(cachedConfig)
+  }
+
+  if (cachedConfigPath !== undefined) {
+    // return JSON.parse(await fs.readFile(cachedConfigPath, 'utf8'))
+    return SerializedCachedConfigSchema.parse(JSON.parse(await fs.readFile(cachedConfigPath, 'utf8')))
+  }
+}