Burst and fast

Choose extra concurrency, higher queue priority, or both for paid tasks.

Two separate controls

Burst lets your account submit work above its normal concurrency limit. Fast raises a task’s queue priority. Neither mode guarantees a completion time, and fast does not increase your concurrency limit.

Both are optional. In the extension popup, turn on Burst or Fast before submitting a challenge. In the API, set the burst and fast booleans on POST /v1/task. Omitting either field is the same as setting it to false.

Burst

Use burst when a short spike would exceed your account’s normal weighted concurrency limit. Recognition tasks use one unit of concurrency; token tasks use ten units. The limit applies across all API keys belonging to the account.

Setting burst: true allows the request to be admitted while the account’s total weighted concurrency stays within five times its normal limit. For example, an account with a 20-unit limit can admit burst tasks up to 100 active units. Each task marked as burst uses the burst price, including requests that fit within normal capacity.

Burst has no activation window or cooldown. A burst request above the five-times limit receives a 429 response. Standard requests still use the normal limit, including when other active tasks were admitted with burst.

Fast

Use fast when queue waiting time matters. Fast gives a task higher priority when workers choose queued work. It does not interrupt tasks already running, change the task timeout, or guarantee that a worker is immediately available.

If you also need extra concurrency, enable burst as well.

Price multipliers

These are the standard multipliers. Your account may have custom rates.

Standard tasks use the base price. When both modes are enabled, apply both multipliers. For recognition, also multiply by the challenge’s group count: nine binary tiles are one group; each area-selection or drag/drop image is one group.

GET /v1/rates returns your current base prices, burst_multiplier, and fast_multiplier. Multiply the base price by the group count and each selected multiplier, then round upward once to a whole microcent. There are 100,000,000 microcents in one USD. The dashboard shows your current rates, and the pricing page lists standard prices.

API example

{
  "type": "hcaptcha_token",
  "sitekey": "YOUR_SITEKEY",
  "url": "https://your-site.test/login",
  "burst": true,
  "fast": true,
  "hold": 30
}

hold only controls how long the response waits. If it ends before completion, use the returned task_id to retrieve the task. A timeout or disconnect does not cancel processing.

The extension’s free plan supports standard recognition only. Burst and fast are unavailable on that plan.