> ## Documentation Index
> Fetch the complete documentation index at: https://tbd-6fc993ce-hypeship-docs-ia-restructure.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Concurrency and Limits

> How many browsers you can run, how fast you can create them, and what each one gets

Three separate limits shape a scaled workload, and they're easy to confuse. Concurrency caps how many browsers exist at once. The create rate caps how fast you can ask for new ones. Per-browser resources cap what one browser can do.

## Concurrency

One org-wide limit covers every browser you're running, whether created on demand with `browsers.create()` or reserved in a [browser pool](/browsers/pools). The full limit is available to either API in any mix.

| Plan       | Concurrent browsers |
| ---------- | ------------------- |
| Developer  | 5                   |
| Hobbyist   | 10                  |
| Start-Up   | 150                 |
| Enterprise | Custom              |

Two things count against it that people don't expect:

* **Reserved pool capacity counts whether or not it's acquired.** A pool sized to 40 browsers uses 40 of your limit for as long as it exists.
* **Browsers in [standby](/browsers/standby) count.** Standby stops usage charges, not the concurrency slot. Delete the browser to release it.

Set per-project caps if you're splitting one org limit across teams, environments, or [tenants](/info/projects#multi-tenant-patterns) — see [project concurrency limits](/info/projects#concurrency-limits).

## Create rate

Browser creation is separately rate limited per plan. This caps how fast you can create browsers, independent of how many you may run:

| Plan       | `browsers.create()` requests per org per minute |
| ---------- | ----------------------------------------------- |
| Developer  | 10                                              |
| Hobbyist   | 25                                              |
| Start-Up   | 100                                             |
| Enterprise | 250                                             |

Acquiring from a [browser pool](/browsers/pools) isn't subject to the create rate — the pool's browsers already exist. If your traffic arrives in bursts, that's the reason to use a pool even when your concurrency headroom is fine.

### What happens at the limit

Exceeding the create rate returns `429 Too Many Requests` with a `Retry-After` header, and rate-limited responses carry `X-RateLimit-Limit` and `X-RateLimit-Remaining`.

All Kernel SDKs retry a `429` up to 2 times, honoring `Retry-After`. If retries are exhausted, the SDK raises a typed `RateLimitError` carrying the response headers, so you can apply your own backoff. Queue on your side rather than tightening the retry loop: a `429` means the org is over budget for the minute, so retrying faster doesn't help.

If you're hitting the ceiling in normal operation, [contact us](https://calendly.com/d/d3tn-5kp-5yt) — the limit is raisable.

## Per-browser resources

| Resource | Headful | Headless |
| -------- | ------- | -------- |
| Memory   | 8 GB    | 1 GB     |

Memory is the practical ceiling on how many tabs and how heavy a page one browser handles. A [headless](/browsers/headless) browser at 1 GB is sized for short-lived, single-page, high-concurrency automation; open a dozen heavy tabs in one and Chromium will start killing renderers. If your workload wants many concurrent pages, spread it across more browsers — that's what concurrency is for — rather than more tabs in one.

[GPU acceleration](/browsers/gpu-acceleration) is a separate browser type with its own [usage rate](/info/pricing#usage-rates), available on Start-Up and Enterprise.

## Other limits worth knowing

| Limit                                                    | Where                                                      |
| -------------------------------------------------------- | ---------------------------------------------------------- |
| Browser `timeout_seconds` (default 60, max 259200 / 72h) | [Termination](/browsers/termination)                       |
| Pool `timeout_seconds` (default 600) and fill rate       | [Browser pools](/browsers/pools)                           |
| App invocation concurrency, per plan and per app         | [Pricing and limits](/info/pricing#concurrency-limits)     |
| Managed auth health check interval, per plan             | [Connection lifecycle](/auth/connection-lifecycle)         |
| Replay retention, extensions, projects, per plan         | [Pricing and limits](/info/pricing#managed-infrastructure) |
| Monthly spend                                            | [Spending caps](/info/spending-caps)                       |