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External apps talk to OpenClaw through the Gateway protocol: WebSocket transport plus RPC methods. Use it when a script, dashboard, CI job, IDE extension, or another process wants to start agent runs, stream events, wait for results, cancel work, or inspect Gateway resources.
For npm packages, device pairing, reconnect recovery, history, subscriptions, and approvals, start with Building a Gateway client. If your app supervises the Gateway as a child process, also read Embedding OpenClaw. During the initial package rollout, npm may return E404 until the first package-bearing OpenClaw release is published.
This page is for code outside the OpenClaw process. Plugin code that runs inside OpenClaw should use documented openclaw/plugin-sdk/* subpaths instead.

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What is available today

  1. Run or discover a Gateway.
  2. Connect over the Gateway protocol.
  3. Call documented RPC methods from Gateway RPC reference.
  4. Pin the OpenClaw version you test against.
  5. Recheck the RPC reference when upgrading OpenClaw.
For agent runs, start with the agent RPC and pair it with agent.wait for a terminal result. For durable conversation state, use the sessions.* methods. For UI integrations, subscribe to Gateway events and render only the event families your app understands.

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Cooperative host suspension

Hosting controllers that freeze or snapshot a running process can use the host-neutral suspension handshake:
  1. Stop admitting external ingress controlled by the host.
  2. Call gateway.suspend.prepare with a stable, unique requestId.
  3. If the response is busy, keep the process running and retry later.
  4. If it is ready, save the returned suspensionId, then freeze or snapshot the process before expiresAtMs.
  5. After thaw, or if suspension is abandoned, call gateway.suspend.resume with that suspensionId over the existing WebSocket or Admin HTTP control path.
A prepared Gateway rejects new WebSocket handshakes. A WebSocket controller must keep its authenticated connection open across the host operation. If that cannot be guaranteed, enable and use the Admin HTTP RPC plugin before preparing. If the control path is lost, wait for the two-minute lease to expire before reconnecting; expiry reopens admission automatically. The RPC contract is:
  • gateway.suspend.prepare — operator.admin; params { "requestId": "stable-host-operation-id" }
  • gateway.suspend.status — operator.read; params { "suspensionId": "id-from-prepare" }
  • gateway.suspend.resume — operator.admin; params { "suspensionId": "id-from-prepare" }
IDs are trimmed, must contain a non-whitespace character, and are limited to 128 characters. A busy prepare result has status: "busy", reason, retryAfterMs, activeCount, and blockers. A ready result has this shape:
Status returns {"status":"running"} or a ready result with expiresAtMs. Resume returns {"ok":true,"status":"running","resumed":true}; repeating it after a successful resume returns resumed: false. A competing request ID or transient scheduler-resume failure returns retryable UNAVAILABLE with retryAfterMs. During scheduler recovery, prepare, status, and resume all return that error, the Gateway remains not-ready and fail-closed, and the host must not freeze or snapshot it. OpenClaw retries the scheduler automatically and reopens admission only after recovery succeeds. A mismatched resume ID returns INVALID_REQUEST. Prepare shares the Gateway’s control-plane write budget of three attempts per minute; honor the returned retry delay. WebSocket clients are bucketed by device and IP. Admin HTTP controllers are bucketed by resolved client IP, so controllers behind one proxy can share a budget. Preparation is refuse-only: OpenClaw closes new root/session/command admission, pauses automatic cron ticks, and inspects work synchronously. If anything is active, it resumes the scheduler and reopens admission before returning busy; it does not interrupt or drain that work. A ready lease lasts two minutes. Repeating prepare with the same requestId renews it; expiry resumes the scheduler before reopening admission. Restart emission that becomes due during a ready lease waits until the lease resumes; an in-flight restart makes preparation return busy. While ready, /healthz remains live and /readyz returns 503. Local or authenticated readiness responses include gateway-draining; unauthenticated remote probes receive only { "ready": false }. The HTTP health probe, suspension methods on existing WebSocket connections, and an already-enabled Admin HTTP RPC route remain available. Other RPCs return retryable UNAVAILABLE. Built-in HTTP user-work routes and ordinary plugin HTTP routes, including OpenAI-compatible APIs, tool/session operations, node watches, and configured hooks, return 503 with error.code: "gateway_unavailable". New plugin-owned WebSocket upgrades also return 503; this covers upgrade ownership, not work performed later over an established plugin socket. This handshake does not persist incoming messages, stop third-party channel transports, or control the hosting platform. The host must fence its ingress before preparation and remains responsible for wake, snapshot/freeze, and stop. activeCount is the aggregate tracked-work count, while blockers contains the non-zero category counts and bounded task details. This is not a general process-quiescence barrier. A background-exec blocker is aggregate only: command text, process IDs, output, and session or scope identifiers never cross the protocol. Channel health, maintenance, cache refresh, established plugin WebSocket sessions, and unregistered plugin-owned background work can remain active. The hosting platform must freeze or snapshot the full process tree and its filesystem consistently; unregistered work cannot be proven idle by this first contract.
For host wake scheduling, keep the OpenClaw-facing part in an in-process plugin and project idempotent full snapshots to the external host adapter. The hosting controller should not import the Plugin SDK or reconstruct cron state from event deltas. See Safe external cron projection.

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App code vs plugin code

Use Gateway RPC when code lives outside OpenClaw:
  • Node scripts that start or observe agent runs
  • CI jobs that call a Gateway
  • dashboards and admin panels
  • IDE extensions
  • external bridges that do not need to become channel plugins
  • integration tests with fake or real Gateway transports
Use the Plugin SDK when code runs inside OpenClaw:
  • provider plugins
  • channel plugins
  • tool or lifecycle hooks
  • agent harness plugins
  • trusted runtime helpers
External apps should not import openclaw/plugin-sdk/*; those subpaths are for plugins loaded by OpenClaw.