diff --git a/.changeset/seven-cooks-tie.md b/.changeset/seven-cooks-tie.md
new file mode 100644
index 0000000000..119f267b16
--- /dev/null
+++ b/.changeset/seven-cooks-tie.md
@@ -0,0 +1,6 @@
+---
+"e2b": patch
+"@e2b/python-sdk": patch
+---
+
+Support overriding sandbox API URL
diff --git a/.github/workflows/cli_tests.yml b/.github/workflows/cli_tests.yml
index 59ba494477..fd105a721b 100644
--- a/.github/workflows/cli_tests.yml
+++ b/.github/workflows/cli_tests.yml
@@ -14,9 +14,6 @@ permissions:
 
 jobs:
   test:
-    defaults:
-      run:
-        working-directory: ./packages/cli
     name: CLI - Build
     runs-on: ubuntu-22.04
     steps:
@@ -32,7 +29,6 @@ jobs:
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4
-        id: pnpm-install
         with:
           version: '${{ env.TOOL_VERSION_PNPM }}'
 
@@ -47,15 +43,20 @@ jobs:
       - name: Configure pnpm
         run: |
           pnpm config set auto-install-peers true
-          pnpm config set exclude-links-from-lockfile true
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
 
-      - name: Test build
+      - name: Build the SDK (pre-requisite for the tests)
         run: pnpm build
+        working-directory: ./packages/js-sdk
+
+      - name: Build the CLI
+        run: pnpm build
+        working-directory: ./packages/cli
 
       - name: Run tests
         run: pnpm test
+        working-directory: ./packages/cli
         env:
           E2B_API_KEY: ${{ secrets.E2B_API_KEY }}
diff --git a/packages/js-sdk/src/connectionConfig.ts b/packages/js-sdk/src/connectionConfig.ts
index edcb9ef222..298dff1dd9 100644
--- a/packages/js-sdk/src/connectionConfig.ts
+++ b/packages/js-sdk/src/connectionConfig.ts
@@ -35,6 +35,12 @@ export interface ConnectionOpts {
    * @default E2B_API_URL // environment variable or `https://api.${domain}`
    */
   apiUrl?: string
+  /**
+   * Sandbox Url to use for the API.
+   * @internal
+   * @default E2B_SANDBOX_URL // environment variable or `https://${port}-${sandboxID}.${domain}`
+   */
+  sandboxUrl?: string
   /**
    * If true the SDK starts in the debug mode and connects to the local envd API server.
    * @internal
@@ -62,9 +68,12 @@ export interface ConnectionOpts {
  * Configuration for connecting to the API.
  */
 export class ConnectionConfig {
+  public static envdPort = 49983
+
   readonly debug: boolean
   readonly domain: string
   readonly apiUrl: string
+  readonly sandboxUrl?: string
   readonly logger?: Logger
 
   readonly requestTimeoutMs: number
@@ -88,6 +97,8 @@ export class ConnectionConfig {
       opts?.apiUrl ||
       ConnectionConfig.apiUrl ||
       (this.debug ? 'http://localhost:3000' : `https://api.${this.domain}`)
+
+    this.sandboxUrl = opts?.sandboxUrl || ConnectionConfig.sandboxUrl
   }
 
   private static get domain() {
@@ -98,6 +109,10 @@ export class ConnectionConfig {
     return getEnvVar('E2B_API_URL')
   }
 
+  private static get sandboxUrl() {
+    return getEnvVar('E2B_SANDBOX_URL')
+  }
+
   private static get debug() {
     return (getEnvVar('E2B_DEBUG') || 'false').toLowerCase() === 'true'
   }
@@ -115,6 +130,25 @@ export class ConnectionConfig {
 
     return timeout ? AbortSignal.timeout(timeout) : undefined
   }
+
+  getSandboxUrl(
+    sandboxId: string,
+    opts: { sandboxDomain: string; envdPort: number }
+  ) {
+    if (this.sandboxUrl) {
+      return this.sandboxUrl
+    }
+
+    return `${this.debug ? 'http' : 'https'}://${this.getHost(sandboxId, opts.envdPort, opts.sandboxDomain)}`
+  }
+
+  getHost(sandboxId: string, port: number, sandboxDomain: string) {
+    if (this.debug) {
+      return `localhost:${port}`
+    }
+
+    return `${port}-${sandboxId}.${sandboxDomain ?? this.domain}`
+  }
 }
 
 /**
diff --git a/packages/js-sdk/src/sandbox/index.ts b/packages/js-sdk/src/sandbox/index.ts
index 9d08bed898..524bf33602 100644
--- a/packages/js-sdk/src/sandbox/index.ts
+++ b/packages/js-sdk/src/sandbox/index.ts
@@ -123,9 +123,15 @@ export class Sandbox extends SandboxApi {
     this.sandboxDomain = opts.sandboxDomain ?? this.connectionConfig.domain
 
     this.envdAccessToken = opts.envdAccessToken
-    this.envdApiUrl = `${
-      this.connectionConfig.debug ? 'http' : 'https'
-    }://${this.getHost(this.envdPort)}`
+    this.envdApiUrl = this.connectionConfig.getSandboxUrl(this.sandboxId, {
+      sandboxDomain: this.sandboxDomain,
+      envdPort: this.envdPort,
+    })
+
+    const sandboxHeaders = {
+      'E2b-Sandbox-Id': this.sandboxId,
+      'E2b-Sandbox-Port': this.envdPort.toString(),
+    }
 
     const rpcTransport = createConnectTransport({
       baseUrl: this.envdApiUrl,
@@ -141,6 +147,9 @@ export class Sandbox extends SandboxApi {
         new Headers(options?.headers).forEach((value, key) =>
           headers.append(key, value)
         )
+        new Headers(sandboxHeaders).forEach((value, key) =>
+          headers.append(key, value)
+        )
 
         if (this.envdAccessToken) {
           headers.append('X-Access-Token', this.envdAccessToken)
@@ -459,11 +468,11 @@ export class Sandbox extends SandboxApi {
    * ```
    */
   getHost(port: number) {
-    if (this.connectionConfig.debug) {
-      return `localhost:${port}`
-    }
-
-    return `${port}-${this.sandboxId}.${this.sandboxDomain}`
+    return this.connectionConfig.getHost(
+      this.sandboxId,
+      port,
+      this.sandboxDomain
+    )
   }
 
   /**
diff --git a/packages/js-sdk/src/sandbox/sandboxApi.ts b/packages/js-sdk/src/sandbox/sandboxApi.ts
index 6599d46e83..0c49d349b2 100644
--- a/packages/js-sdk/src/sandbox/sandboxApi.ts
+++ b/packages/js-sdk/src/sandbox/sandboxApi.ts
@@ -90,6 +90,11 @@ export interface SandboxOpts extends ConnectionOpts {
    * @default undefined
    */
   mcp?: McpServer
+
+  /**
+   * Sandbox URL. Used for local development
+   */
+  sandboxUrl?: string
 }
 
 export type SandboxBetaCreateOpts = SandboxOpts & {
diff --git a/packages/python-sdk/e2b/connection_config.py b/packages/python-sdk/e2b/connection_config.py
index e20ae4ba07..efc89091a6 100644
--- a/packages/python-sdk/e2b/connection_config.py
+++ b/packages/python-sdk/e2b/connection_config.py
@@ -40,12 +40,17 @@ class ApiParams(TypedDict, total=False):
     proxy: Optional[ProxyTypes]
     """Proxy to use for the request. In case of a sandbox it applies to all **requests made to the returned sandbox**."""
 
+    sandbox_url: Optional[str]
+    """URL to connect to sandbox, defaults to `E2B_SANDBOX_URL` environment variable."""
+
 
 class ConnectionConfig:
     """
     Configuration for the connection to the API.
     """
 
+    envd_port = 49983
+
     @staticmethod
     def _domain():
         return os.getenv("E2B_DOMAIN") or "e2b.app"
@@ -62,6 +67,10 @@ def _api_key():
     def _api_url():
         return os.getenv("E2B_API_URL")
 
+    @staticmethod
+    def _sandbox_url():
+        return os.getenv("E2B_SANDBOX_URL")
+
     @staticmethod
     def _access_token():
         return os.getenv("E2B_ACCESS_TOKEN")
@@ -72,6 +81,7 @@ def __init__(
         debug: Optional[bool] = None,
         api_key: Optional[str] = None,
         api_url: Optional[str] = None,
+        sandbox_url: Optional[str] = None,
         access_token: Optional[str] = None,
         request_timeout: Optional[float] = None,
         headers: Optional[Dict[str, str]] = None,
@@ -106,6 +116,8 @@ def __init__(
             or ("http://localhost:3000" if self.debug else f"https://api.{self.domain}")
         )
 
+        self._sandbox_url = sandbox_url or ConnectionConfig._sandbox_url()
+
     @staticmethod
     def _get_request_timeout(
         default_timeout: Optional[float],
@@ -121,6 +133,28 @@ def _get_request_timeout(
     def get_request_timeout(self, request_timeout: Optional[float] = None):
         return self._get_request_timeout(self.request_timeout, request_timeout)
 
+    def get_sandbox_url(self, sandbox_id: str, sandbox_domain: str) -> str:
+        if self._sandbox_url:
+            return self._sandbox_url
+
+        return f"{'http' if self.debug else 'https'}://{self.get_host(sandbox_id, sandbox_domain, self.envd_port)}"
+
+    def get_host(self, sandbox_id: str, sandbox_domain: str, port: int) -> str:
+        """
+        Get the host address to connect to the sandbox.
+        You can then use this address to connect to the sandbox port from outside the sandbox via HTTP or WebSocket.
+
+        :param port: Port to connect to
+        :param sandbox_domain: Domain to connect to
+        :param sandbox_id: Sandbox to connect to
+
+        :return: Host address to connect to
+        """
+        if self.debug:
+            return f"localhost:{port}"
+
+        return f"{port}-{sandbox_id}.{sandbox_domain}"
+
     def get_api_params(
         self,
         **opts: Unpack[ApiParams],
diff --git a/packages/python-sdk/e2b/sandbox/main.py b/packages/python-sdk/e2b/sandbox/main.py
index b0a5f3b221..c1b028a705 100644
--- a/packages/python-sdk/e2b/sandbox/main.py
+++ b/packages/python-sdk/e2b/sandbox/main.py
@@ -15,6 +15,7 @@ class SandboxOpts(TypedDict):
     sandbox_domain: Optional[str]
     envd_version: Version
     envd_access_token: Optional[str]
+    sandbox_url: Optional[str]
     connection_config: ConnectionConfig
 
 
@@ -25,7 +26,6 @@ class SandboxBase:
         keepalive_expiry=300,
     )
 
-    envd_port = 49983
     mcp_port = 50005
 
     default_sandbox_timeout = 300
@@ -46,7 +46,9 @@ def __init__(
         self.__sandbox_domain = sandbox_domain or self.connection_config.domain
         self.__envd_version = envd_version
         self.__envd_access_token = envd_access_token
-        self.__envd_api_url = f"{'http' if self.connection_config.debug else 'https'}://{self.get_host(self.envd_port)}"
+        self.__envd_api_url = self.connection_config.get_sandbox_url(
+            self.sandbox_id, self.sandbox_domain
+        )
         self.__mcp_token: Optional[str] = None
 
     @property
@@ -195,10 +197,9 @@ def get_host(self, port: int) -> str:
 
         :return: Host address to connect to
         """
-        if self.connection_config.debug:
-            return f"localhost:{port}"
-
-        return f"{port}-{self.sandbox_id}.{self.sandbox_domain}"
+        return self.connection_config.get_host(
+            self.sandbox_id, self.sandbox_domain, port
+        )
 
     def get_mcp_url(self) -> str:
         """
diff --git a/packages/python-sdk/e2b/sandbox_async/main.py b/packages/python-sdk/e2b/sandbox_async/main.py
index 66ad933064..6e514c9222 100644
--- a/packages/python-sdk/e2b/sandbox_async/main.py
+++ b/packages/python-sdk/e2b/sandbox_async/main.py
@@ -95,7 +95,9 @@ def __init__(self, **opts: Unpack[SandboxOpts]):
             limits=self._limits, proxy=self.connection_config.proxy
         )
         self._envd_api = httpx.AsyncClient(
-            base_url=self.envd_api_url,
+            base_url=self.connection_config.get_sandbox_url(
+                self.sandbox_id, self.sandbox_domain
+            ),
             transport=self._transport,
             headers=self.connection_config.sandbox_headers,
         )
@@ -721,6 +723,9 @@ async def _create(
             ):
                 extra_sandbox_headers["X-Access-Token"] = envd_access_token
 
+        extra_sandbox_headers["E2b-Sandbox-Id"] = sandbox_id
+        extra_sandbox_headers["E2b-Sandbox-Port"] = str(ConnectionConfig.envd_port)
+
         connection_config = ConnectionConfig(
             extra_sandbox_headers=extra_sandbox_headers,
             **opts,
diff --git a/packages/python-sdk/e2b/sandbox_async/sandbox_api.py b/packages/python-sdk/e2b/sandbox_async/sandbox_api.py
index a41b75f27e..84bf11fa2b 100644
--- a/packages/python-sdk/e2b/sandbox_async/sandbox_api.py
+++ b/packages/python-sdk/e2b/sandbox_async/sandbox_api.py
@@ -310,6 +310,10 @@ async def _cls_connect(
         async with AsyncApiClient(
             config,
             limits=SandboxBase._limits,
+            headers={
+                "E2b-Sandbox-Id": sandbox_id,
+                "E2b-Sandbox-Port": config.envd_port,
+            },
         ) as api_client:
             res = await post_sandboxes_sandbox_id_connect.asyncio_detailed(
                 sandbox_id,
diff --git a/packages/python-sdk/e2b/sandbox_sync/main.py b/packages/python-sdk/e2b/sandbox_sync/main.py
index 9c39f74327..1e82a4bca5 100644
--- a/packages/python-sdk/e2b/sandbox_sync/main.py
+++ b/packages/python-sdk/e2b/sandbox_sync/main.py
@@ -718,6 +718,9 @@ def _create(
             ):
                 extra_sandbox_headers["X-Access-Token"] = envd_access_token
 
+        extra_sandbox_headers["E2b-Sandbox-Id"] = sandbox_id
+        extra_sandbox_headers["E2b-Sandbox-Port"] = str(ConnectionConfig.envd_port)
+
         connection_config = ConnectionConfig(
             extra_sandbox_headers=extra_sandbox_headers,
             **opts,
diff --git a/packages/python-sdk/e2b/sandbox_sync/sandbox_api.py b/packages/python-sdk/e2b/sandbox_sync/sandbox_api.py
index 7052a1e9ff..1600e19dcd 100644
--- a/packages/python-sdk/e2b/sandbox_sync/sandbox_api.py
+++ b/packages/python-sdk/e2b/sandbox_sync/sandbox_api.py
@@ -264,6 +264,10 @@ def _cls_connect(
         with ApiClient(
             config,
             limits=SandboxBase._limits,
+            headers={
+                "E2b-Sandbox-Id": sandbox_id,
+                "E2b-Sandbox-Port": config.envd_port,
+            },
         ) as api_client:
             res = post_sandboxes_sandbox_id_connect.sync_detailed(
                 sandbox_id,
diff --git a/packages/python-sdk/e2b_connect/client.py b/packages/python-sdk/e2b_connect/client.py
index 863ddf3d61..034a8478df 100644
--- a/packages/python-sdk/e2b_connect/client.py
+++ b/packages/python-sdk/e2b_connect/client.py
@@ -287,9 +287,10 @@ def _prepare_server_stream_request(
         req,
         request_timeout=None,
         timeout=None,
-        headers={},
+        headers=None,
         **opts,
     ):
+        headers = headers or {}
         data = self._codec.encode(req)
         flags = EnvelopeFlags(0)
 
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index b6707e60ff..54724ea9f7 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -273,7 +273,7 @@ importers:
         version: 0.6.1
       e2b:
         specifier: ^2.6.1
-        version: 2.6.1
+        version: link:../js-sdk
       handlebars:
         specifier: ^4.7.8
         version: 4.7.8
@@ -4078,10 +4078,6 @@ packages:
     resolution: {integrity: sha512-KIN/nDJBQRcXw0MLVhZE9iQHmG68qAVIBg9CqmUYjmQIhgij9U5MFvrqkUL5FbtyyzZuOeOt0zdeRe4UY7ct+A==}
     engines: {node: '>= 0.4'}
 
-  e2b@2.6.1:
-    resolution: {integrity: sha512-KYQOza4bYNWTbbwbTHNlgOVWXKtlq2c1H0I5jW1Q1kEFYqoKxjfZGtkuJjnOtmVpeiIKzsMtQ9n0e3WKHBDysQ==}
-    engines: {node: '>=20'}
-
   e2b@2.6.4:
     resolution: {integrity: sha512-IhtNZxXomub24lSmq/eldOC4HfK8YqTpxGqL3MAxNlF4ggyS6hde9D0euW40zZL3VoCFD8wjcwKrdYtM1tVDZw==}
     engines: {node: '>=20'}
@@ -12158,19 +12154,6 @@ snapshots:
       es-errors: 1.3.0
       gopd: 1.2.0
 
-  e2b@2.6.1:
-    dependencies:
-      '@bufbuild/protobuf': 2.6.2
-      '@connectrpc/connect': 2.0.0-rc.3(@bufbuild/protobuf@2.6.2)
-      '@connectrpc/connect-web': 2.0.0-rc.3(@bufbuild/protobuf@2.6.2)(@connectrpc/connect@2.0.0-rc.3(@bufbuild/protobuf@2.6.2))
-      chalk: 5.3.0
-      compare-versions: 6.1.1
-      dockerfile-ast: 0.7.1
-      glob: 11.0.3
-      openapi-fetch: 0.14.1
-      platform: 1.3.6
-      tar: 7.4.3
-
   e2b@2.6.4:
     dependencies:
       '@bufbuild/protobuf': 2.6.2