---
title: "Keep an Auto Dojo sim session alive (liveness lease)."
method: POST
path: "/sim/{session_id}/heartbeat"
tags: ["Dojo"]
---

# Keep an Auto Dojo sim session alive (liveness lease).

`POST /sim/{session_id}/heartbeat`

## Request

- Base URL: `https://api.mnemom.ai/v1`
- URL: `https://api.mnemom.ai/v1/sim/{session_id}/heartbeat`
- Auth: one of:
  - HTTP bearer
  - API key in header `X-Mnemom-Api-Key`

The dashboard POSTs this ~every 10s while it is actively watching an Auto run. The runner stops the run gracefully if no heartbeat arrives within its grace window, so a closed/abandoned tab can't keep driving the gateway. Idempotent; returns `{ running: false }` once the session has ended. MNE-782.

## Path parameters

- `session_id` string, uuid, required

## Response `200`

Heartbeat recorded (or no-op when the session is not running).

- object
  - `ok` boolean
  - `running` boolean

## Other responses

- `400`: Bad request
- `401`: Authentication required
- `403`: Forbidden
- `404`: Resource not found
- `429`: Rate-limit exceeded. The global per-IP limiter (100 requests/minute, applied to every `/v1/*` route) rejected this request. Back off until the window resets — `Retry-After` carries the cooldown in seconds and `X-RateLimit-Reset` the absolute reset time.
- `500`: Server error — request was well-formed but the server failed to fulfill it. Typically a downstream dependency (DB / RPC / external API) returned an unexpected error.

---

[API](https://skmtc.dev/mnemom/apis/mnemom-api.md) · [All operations](https://skmtc.dev/mnemom/apis/mnemom-api/llms.txt) · [OpenAPI document](https://skmtc.dev/mnemom/apis/mnemom-api/revisions/274b7a6ea182?raw)