---
title: "Open a cloud browser session"
method: POST
path: "/browser-sessions/session"
tags: ["Agent browsers"]
---

# Open a cloud browser session

`POST /browser-sessions/session`

Returns session identity, engine, bootId and runKey. Same runKey and policy reuse the session; omit runKey for a new isolated browser. Request bodies are limited to 64,000 characters.

## Request body

- object
  - `projectId` string, required
  - `policy` object, required
    - `mode` 'allow_all' | 'read_only' | 'allowlist', required
    - `originAllowlist` string[]
    - `toolAllowlist` string[]
  - `runKey` string
  - `profile` 'persistent'

## Response `200`

Returns session identity, engine, bootId and runKey. Same runKey and policy reuse the session; omit runKey for a new isolated browser.

- object

## Other responses

- `400` — Invalid request or policy
- `401` — Authentication required
- `403` — Access denied
- `404` — Session not found or not owned by caller
- `409` — Session closed or conflicting command ID
- `429` — Rate limited
- `502` — Browser control plane unavailable

## Changes

- **2026-09-09** `96954aa994ef` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/mcpjam/apis/mcpjam-api/changes/browser-sessions/session/post.md)

---

[API](https://skmtc.dev/mcpjam/apis/mcpjam-api.md) · [All operations](https://skmtc.dev/mcpjam/apis/mcpjam-api/llms.txt) · [OpenAPI document](https://skmtc.dev/mcpjam/apis/mcpjam-api/revisions/a15a9864fb85?raw)