E2B 2.56.0 requires Node 22.19+ and drops request cap

E2B shipped release e2b@2.56.0 on October 13, 2026, according to the GitHub release published by the e2b-dev/E2B repository. The release raises the Node.js requirement and changes how the SDK handles concurrent requests, including one breaking change.

Release facts

What changed

• Node.js 22.19.0 or newer required. The release notes say the SDK now depends on undici@^8 only, and undici 7 is dropped.
• Node.js 20 no longer supported. A separate entry requires Node.js 22 or newer.
• Connection handling. According to the release notes, undici 8 respects the server's HTTP/2 SETTINGS_MAX_CONCURRENT_STREAMS and opens more connections when one is saturated.
• Breaking: in-flight request cap removed. The SDK-level cap is gone, along with the E2B_API_INFLIGHT_REQUESTS, E2B_ENVD_INFLIGHT_REQUESTS and E2B_ENVD_RPC_INFLIGHT_REQUESTS environment variables. Concurrency is governed by undici's connection pools (E2B_API_CONNECTIONS, E2B_ENVD_RPC_CONNECTIONS).
• Dependency bump. @e2b/dockerfile-utils is updated to 0.1.1.

Questions

Do I need to change my Node.js version? Yes if you run Node.js 20 or an older 22 release. The release notes require Node.js 22.19.0 or newer and state that Node.js 20 is no longer supported.

What happens to the in-flight request environment variables? The release notes say the three *_INFLIGHT_REQUESTS variables are removed. Concurrency is instead governed by E2B_API_CONNECTIONS and E2B_ENVD_RPC_CONNECTIONS.

What is E2B? The repository describes it as an open-source, secure environment with real-world tools for enterprise-grade agents. The documentation describes a sandbox as a Linux VM created on demand for an agent.

See the e2b tool hub, the agent infra category, and the related adk-python 2.12.0 launch for more.