---
title: "Acquire a browser from the pool"
method: POST
path: "/browser_pools/{id_or_name}/acquire"
tags: ["Browser Pools"]
---

# Acquire a browser from the pool

`POST /browser_pools/{id_or_name}/acquire`

Long-polling endpoint to acquire a browser from the pool. Returns immediately when a browser
is available, or returns 204 No Content when the poll times out. The client should retry
the request to continue waiting for a browser. The acquired browser will use the pool's
timeout_seconds for its idle timeout.

## Path parameters

- `id_or_name` string, required

## Request body

- BrowserPoolAcquireRequest — Request body for acquiring a browser from the pool.
  - `acquire_timeout_seconds` integer — Maximum number of seconds to wait for a browser to be available. Defaults to the calculated time it would take to fill the pool at the currently configured fill rate.
  - `name` string — Optional human-readable name for the acquired browser session, used to find it later in the dashboard. Must be unique among active sessions within the pool's project. Applies to this lease only and is cleared when the browser is released back to the pool.
  - `start_url` string — Optional URL to navigate the acquired browser to. Overrides the pool's start_url for this acquire only. Best-effort: failures to navigate do not fail the acquire.
  - `tags` Tags — User-defined key-value tags.
  - `telemetry` BrowserTelemetryRequestConfig — Telemetry request configuration for a browser session.
    - `browser` BrowserTelemetryCategoriesConfig — Per-category telemetry capture settings layered onto the default set. The operational signals (control, connection, system, captcha) are on by default and are opt-out: set one to enabled=false to stop capturing it. The CDP categories (console, network, page, interaction), screenshot and platform are off by default and are opt-in: set enabled=true to capture them.
      - `captcha` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `connection` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `console` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `control` BrowserTelemetryControlConfig — Configuration for the control category. Same enabled semantics as any other category, plus settings for the browser-control commands the CDP proxy reports.
        - `cdp` BrowserTelemetryCdpControlConfig — Settings for the cdp_command events the CDP proxy reports.
          - `excluded_methods` BrowserCdpCommandMethod[] — Methods to leave out of the cdp_command stream. Omit the list to keep the current one; send an empty list to report every supported method again. Exclusion is a telemetry setting only: an excluded command is still relayed to the browser unchanged, it simply produces no event. Use it to drop the highest-volume methods — Input.dispatchMouseEvent during a humanized cursor path, or Page.captureScreenshot under a screencast — without turning the whole category off. Excluded commands are counted in cdp_disconnect.telemetry_excluded.
        - `enabled` boolean — Whether this category is captured. Control is on by default; set false to opt out.
      - `interaction` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `network` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `page` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `platform` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `screenshot` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `system` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
    - `enabled` boolean — Request shortcut for browser telemetry capture. True enables capture; with no browser category settings it captures the default set (control, connection, system, captcha), and any browser category settings are layered onto that default set. On update, enabled=true resolves the config fresh from the default set plus any provided categories, replacing the session's current selection rather than merging onto it; omit enabled to merge categories onto the current selection instead. False stops capture on update and starts no capture on create. enabled=false cannot be combined with browser category settings.
    - `export` BrowserTelemetryExportRequestConfig — Export destinations for a session's captured telemetry, by protocol. Honored when creating a browser, including the browser a managed auth connection creates for a login. Browser pools do not support export and reject it; on a browser update it is ignored, so the session keeps the destination it was created with.
      - `otlp` BrowserTelemetryOTLPExportRequestConfig — OTLP export settings for a browser session.
        - `destination` union — OTLP destination selection. Provide either id or name. The destination must exist in the project the request resolves to.
          - object
            - `id` string, required — OTLP destination ID
            - `name` string — OTLP destination name
          - object
            - `id` string — OTLP destination ID
            - `name` string, required — OTLP destination name
        - `enabled` boolean — Whether to export captured telemetry over OTLP. Setting destination implies enabled=true, so this only needs to be set explicitly to disable export (enabled=false with a destination is rejected).

## Response `200`

Browser acquired successfully

- Browser
  - `base_url` string — Metro-API HTTP base URL for this browser session.
  - `browser_live_view_url` string — Remote URL for live viewing the browser session. Only available for non-headless browsers.
  - `cdp_ws_url` string, required — Websocket URL for Chrome DevTools Protocol connections to the browser session
  - `chrome_policy` object — Custom Chrome enterprise policy overrides that were applied to this browser session, if any. Echoed back for verification. Keys are Chrome enterprise policy names.
  - `created_at` string, date-time, required — When the browser session was created.
  - `deleted_at` string, date-time — When the browser session was soft-deleted. Only present for deleted sessions.
  - `gpu` boolean — Whether GPU acceleration is enabled for the browser session (only supported for headful sessions).
  - `headless` boolean, required — Whether the browser session is running in headless mode.
  - `kiosk_mode` boolean — Whether the browser session is running in kiosk mode.
  - `memory` '1GiB' | '2GiB' | '6GiB' | '8GiB' | '16GiB', required — Memory allocated to the browser session.
  - `name` string — Human-readable name of the browser session, if one was set at creation.
  - `network` BrowserNetworkConfig — Network configuration for a browser session or browser pool.
    - `private_hosts` string[] — Destinations the browser reaches directly through the session's own network instead of through Kernel-managed egress — for private hosts reachable over a VPN or tunnel the session has joined (e.g. a Tailscale tailnet). By default, private IP ranges already route directly: RFC1918 (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), CGNAT/Tailscale (100.64.0.0/10), and IPv6 ULA (fc00::/7). An explicitly supplied list replaces those defaults with exactly the entries given, and an empty list ([]) disables them so all traffic uses Kernel-managed egress; omit private_hosts to keep the defaults. Entries are hostname patterns ("*.example.ts.net", "preview.internal") or IP/CIDR literals ("100.64.0.0/10", "10.1.30.63"). IP and CIDR entries only match URLs written with a literal IP address; they never match hostnames that resolve into the range, so private DNS names need a hostname entry even when they resolve inside the default ranges. CIDRs must be in canonical masked form (host bits zero), and only the private ranges listed above are accepted; public, loopback, link-local, and unspecified ranges are rejected. Exact IPv6 addresses must be bracketed ("[fd00::1]"); IPv6 CIDR ranges are unbracketed ("fd00::/8"). Wildcards are limited to one leading "*." over a suffix with at least two labels that is not a public suffix (so "*.co.uk" or "*.ts.net" are rejected, while "*.example.ts.net" is accepted). Hostname and IP entries may carry a port; CIDR ranges may not. Hostname entries are not resolved during validation, so callers must ensure they identify private destinations. Not related to a proxy's bypass_hosts, which selects between upstream-proxy and Kernel-managed direct egress and cannot reach into a VPN.
  - `pool` BrowserPoolRef — Browser pool this session was acquired from, if any.
    - `id` string, required — Browser pool ID
    - `name` string — Browser pool name, if set
  - `profile` Profile — Browser profile metadata.
    - `created_at` string, date-time, required — Timestamp when the profile was created
    - `id` string, required — Unique identifier for the profile
    - `last_used_at` string, date-time — Timestamp when the profile was last used
    - `name` string, nullable — Optional, easier-to-reference name for the profile
    - `updated_at` string, date-time — Timestamp when the profile was last updated
  - `profile_save_changes` boolean — Whether changes made during this browser session are saved back to its profile when the session ends. Omitted when no profile is attached.
  - `proxy` union — Resolved proxy configuration for a browser session. Selected proxies are returned by stable ID.
    - object
      - `id` string — Selected proxy ID.
      - `mode` 'direct' | 'default', required — Proxy egress mode. direct forces no proxy regardless of stealth. default uses the browser's stealth-derived default: Kernel's default stealth proxy when stealth=true, or direct egress when stealth=false. default is primarily useful on browser update to restore the browser default after selected-proxy egress.
      - `name` string — Selected proxy name.
    - object
      - `id` string, required — Selected proxy ID.
      - `mode` 'direct' | 'default' — Proxy egress mode. direct forces no proxy regardless of stealth. default uses the browser's stealth-derived default: Kernel's default stealth proxy when stealth=true, or direct egress when stealth=false. default is primarily useful on browser update to restore the browser default after selected-proxy egress.
      - `name` string — Selected proxy name.
    - object
      - `id` string — Selected proxy ID.
      - `mode` 'direct' | 'default' — Proxy egress mode. direct forces no proxy regardless of stealth. default uses the browser's stealth-derived default: Kernel's default stealth proxy when stealth=true, or direct egress when stealth=false. default is primarily useful on browser update to restore the browser default after selected-proxy egress.
      - `name` string, required — Selected proxy name.
  - `proxy_id` string — ID of the proxy associated with this browser session, if any. Deprecated in favor of proxy.
  - `region` 'us-east' | 'eu-west', required — Geographic region for hosting browser sessions or pools.
  - `session_id` string, required — Unique identifier for the browser session
  - `start_url` string — URL the session was asked to navigate to on creation, if any. Recorded for debugging. Navigation is fire-and-forget — the URL is dispatched to the browser without waiting for it to load, and any errors (DNS failure, bad status, timeout) are silently dropped. Captures what was requested, not what the browser actually loaded.
  - `stealth` boolean, required — Whether the browser session is running in stealth mode.
  - `tags` Tags — User-defined key-value tags.
  - `telemetry` BrowserTelemetryConfig — Active telemetry configuration for a browser session.
    - `browser` BrowserTelemetryCategoriesConfig — Per-category telemetry capture settings layered onto the default set. The operational signals (control, connection, system, captcha) are on by default and are opt-out: set one to enabled=false to stop capturing it. The CDP categories (console, network, page, interaction), screenshot and platform are off by default and are opt-in: set enabled=true to capture them.
      - `captcha` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `connection` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `console` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `control` BrowserTelemetryControlConfig — Configuration for the control category. Same enabled semantics as any other category, plus settings for the browser-control commands the CDP proxy reports.
        - `cdp` BrowserTelemetryCdpControlConfig — Settings for the cdp_command events the CDP proxy reports.
          - `excluded_methods` BrowserCdpCommandMethod[] — Methods to leave out of the cdp_command stream. Omit the list to keep the current one; send an empty list to report every supported method again. Exclusion is a telemetry setting only: an excluded command is still relayed to the browser unchanged, it simply produces no event. Use it to drop the highest-volume methods — Input.dispatchMouseEvent during a humanized cursor path, or Page.captureScreenshot under a screencast — without turning the whole category off. Excluded commands are counted in cdp_disconnect.telemetry_excluded.
        - `enabled` boolean — Whether this category is captured. Control is on by default; set false to opt out.
      - `interaction` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `network` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `page` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `platform` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `screenshot` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
      - `system` BrowserTelemetryCategoryConfig — Per-category telemetry configuration.
        - `enabled` boolean — Whether this category is captured. Operational categories (control, connection, system, captcha) default to true; set false to opt out. CDP categories (console, network, page, interaction), screenshot and platform default to false; set true to opt in.
    - `export` BrowserTelemetryExportConfig — Active export state for a session's captured telemetry, by protocol.
      - `otlp` BrowserTelemetryOTLPExportConfig — Active OTLP export state for a browser session.
        - `destination` string — ID of the OTLP destination the session is bound to. Omitted when the session is not exporting.
        - `enabled` boolean — Whether the session is exporting captured telemetry over OTLP.
  - `timeout_seconds` integer, required — The number of seconds of inactivity before the browser session is terminated.
  - `usage` BrowserUsage — Session usage metrics.
    - `uptime_ms` integer, required — Time in milliseconds the session was actively running.
  - `viewport` BrowserViewport — Initial browser window size in pixels with optional refresh rate. If omitted, image defaults apply (1920x1080@25). For GPU images, the default is 1920x1080@60. Arbitrary viewport dimensions and refresh rates are accepted. Known-good presets include: 2560x1440@10, 1920x1080@25, 1920x1200@25, 1440x900@25, 1280x800@60, 1024x768@60, 1200x800@60, 768x1024@60, 390x844@60. For GPU images, recommended presets use one of these resolutions with refresh rates 60, 30, 25, or 10: 800x600, 960x720, 1024x576, 1024x768, 1152x648, 1200x800, 1280x720, 1368x768, 1440x900, 1600x900, 1920x1080, 1920x1200, 390x844, 360x250, 768x1024, 800x1600. Viewports outside this list may exhibit unstable live view or recording behavior. If refresh_rate is not provided, it will be automatically determined based on the resolution (higher resolutions use lower refresh rates to keep bandwidth reasonable).
    - `height` integer, required — Browser window height in pixels. Any positive integer is accepted.
    - `refresh_rate` integer — Display refresh rate in Hz. Any positive integer is accepted; if omitted, automatically determined from width and height.
    - `width` integer, required — Browser window width in pixels. Any positive integer is accepted.
  - `webdriver_ws_url` string, required — Websocket URL for WebDriver BiDi connections to the browser session

## Other responses

- `204` — Poll timed out, no browser available. Retry the request to continue waiting.
- `400` — Bad Request – invalid input
- `401` — Unauthorized – missing or invalid authorization token
- `403` — Forbidden – insufficient permissions or plan
- `404` — Resource not found
- `409` — Conflict – resource already exists
- `500` — Internal Server Error

---

[API](https://skmtc.net/onkernel/apis/kernel-api.md) · [All operations](https://skmtc.net/onkernel/apis/kernel-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/onkernel/kernel-api/revisions/858365328f92/schema)