diff --git a/package-lock.json b/package-lock.json
index 8759a701..b4606f00 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -18,7 +18,6 @@
         "express": "^5.0.1",
         "express-rate-limit": "^7.5.0",
         "pkce-challenge": "^5.0.0",
-        "raw-body": "^3.0.0",
         "zod": "^3.23.8",
         "zod-to-json-schema": "^3.24.1"
       },
diff --git a/package.json b/package.json
index 8be8f100..30205b1c 100644
--- a/package.json
+++ b/package.json
@@ -71,7 +71,6 @@
     "express": "^5.0.1",
     "express-rate-limit": "^7.5.0",
     "pkce-challenge": "^5.0.0",
-    "raw-body": "^3.0.0",
     "zod": "^3.23.8",
     "zod-to-json-schema": "^3.24.1"
   },
@@ -100,4 +99,4 @@
   "resolutions": {
     "strip-ansi": "6.0.1"
   }
-}
\ No newline at end of file
+}
diff --git a/src/server/sse.ts b/src/server/sse.ts
index e0725686..aa4e9cfd 100644
--- a/src/server/sse.ts
+++ b/src/server/sse.ts
@@ -2,12 +2,11 @@ import { randomUUID } from "node:crypto";
 import { IncomingMessage, ServerResponse } from "node:http";
 import { Transport } from "../shared/transport.js";
 import { JSONRPCMessage, JSONRPCMessageSchema, MessageExtraInfo, RequestInfo } from "../types.js";
-import getRawBody from "raw-body";
 import contentType from "content-type";
 import { AuthInfo } from "./auth/types.js";
 import { URL } from 'url';
 
-const MAXIMUM_MESSAGE_SIZE = "4mb";
+const MAXIMUM_MESSAGE_SIZE = 4 * 1024 * 1024; // 4MB
 
 /**
  * Configuration options for SSEServerTransport.
@@ -161,7 +160,7 @@ export class SSEServerTransport implements Transport {
 
       body = parsedBody ?? await getRawBody(req, {
         limit: MAXIMUM_MESSAGE_SIZE,
-        encoding: ct.parameters.charset ?? "utf-8",
+        encoding: (ct.parameters.charset as BufferEncoding) ?? "utf-8",
       });
     } catch (error) {
       res.writeHead(400).end(String(error));
@@ -219,3 +218,27 @@ export class SSEServerTransport implements Transport {
     return this._sessionId;
   }
 }
+
+export function getRawBody(req: IncomingMessage, { limit, encoding }: { limit: number, encoding: BufferEncoding }) {
+  return new Promise<string>((resolve, reject) => {
+    let received = 0;
+
+    const chunks: Buffer[] = [];
+    req.on("data", (chunk: Buffer) => {
+      received += chunk.length;
+      if (received > limit)
+        return reject(new Error(`Message size exceeds limit of ${limit} bytes`));
+      chunks.push(chunk);
+    });
+    req.on('end', () => {
+      try {
+        resolve(Buffer.concat(chunks).toString(encoding));
+      } catch (error) {
+        reject(error);
+      }
+    });
+    req.on('error', (error) => {
+      reject(error);
+    });
+  });
+}
\ No newline at end of file
diff --git a/src/server/streamableHttp.ts b/src/server/streamableHttp.ts
index 3bf84e43..aef475df 100644
--- a/src/server/streamableHttp.ts
+++ b/src/server/streamableHttp.ts
@@ -1,12 +1,12 @@
 import { IncomingMessage, ServerResponse } from "node:http";
 import { Transport } from "../shared/transport.js";
 import { MessageExtraInfo, RequestInfo, isInitializeRequest, isJSONRPCError, isJSONRPCRequest, isJSONRPCResponse, JSONRPCMessage, JSONRPCMessageSchema, RequestId, SUPPORTED_PROTOCOL_VERSIONS, DEFAULT_NEGOTIATED_PROTOCOL_VERSION } from "../types.js";
-import getRawBody from "raw-body";
 import contentType from "content-type";
 import { randomUUID } from "node:crypto";
 import { AuthInfo } from "./auth/types.js";
+import { getRawBody } from "./sse.js";
 
-const MAXIMUM_MESSAGE_SIZE = "4mb";
+const MAXIMUM_MESSAGE_SIZE = 4 * 1024 * 1024; // 4MB
 
 export type StreamId = string;
 export type EventId = string;
@@ -412,9 +412,9 @@ export class StreamableHTTPServerTransport implements Transport {
         const parsedCt = contentType.parse(ct);
         const body = await getRawBody(req, {
           limit: MAXIMUM_MESSAGE_SIZE,
-          encoding: parsedCt.parameters.charset ?? "utf-8",
+          encoding: (parsedCt.parameters.charset as BufferEncoding) ?? "utf-8",
         });
-        rawMessage = JSON.parse(body.toString());
+        rawMessage = JSON.parse(body);
       }
 
       let messages: JSONRPCMessage[];