Rate Limits

API access requires Pro credits — available pay-as-you-go or via subscription. Signing up free grants 500 Pro credits immediately.

Concurrency limits

Each account can have up to 18 jobs queued + running at a time. Submitting beyond this limit returns 429 with a Retry-After header.

Up to 6 of those jobs will run concurrently — additional jobs stay queued until a running slot opens. Creating multiple API keys does not increase these limits; they are per account.

Response headers

Header	When	Value
`Retry-After`	`429` response	Seconds to wait before retrying

Polling rate limit

Each job can be polled at a sustained rate of 1 request per second per API key. A token bucket allows bursting up to 30 requests — after which requests are limited to 1/second until the bucket refills. If you exceed this, the API returns 429 with a Retry-After header.

Most compressions complete in under 10 seconds — the recommended intervals below keep you well within limits.

Recommended polling intervals

Compression type	Poll interval
Images (JPG, PNG, GIF)	1-2 seconds
Universal image (37+ formats)	2-3 seconds
PDF documents	3-5 seconds
Office documents (DOCX, PPTX)	3-5 seconds
Large files (> 50 MB)	5-10 seconds

Best practices

Respect Retry-After — wait the indicated seconds before retrying.
Exponential backoff — if no Retry-After header, back off: 1s, 2s, 4s, 8s, max 30s.
Poll, don't spin — use the intervals above instead of tight loops.

Errors

Webhooks

# Rate Limits

API access requires Pro credits — available pay-as-you-go or via subscription. Signing up free grants 500 Pro credits immediately.

## Concurrency limits

Each account can have up to **{{pool-max-queued}} jobs queued + running** at a time. Submitting beyond this limit returns `429` with a `Retry-After` header.

Up to **{{pool-max-running}}** of those jobs will run concurrently — additional jobs stay queued until a running slot opens. Creating multiple API keys does not increase these limits; they are per account.

## Response headers

| Header | When | Value |
|--------|------|-------|
| `Retry-After` | `429` response | Seconds to wait before retrying |

## Polling rate limit

Each job can be polled at a sustained rate of **1 request per second** per API key. A token bucket allows bursting up to **30 requests** — after which requests are limited to 1/second until the bucket refills. If you exceed this, the API returns `429` with a `Retry-After` header.

Most compressions complete in under 10 seconds — the recommended intervals below keep you well within limits.

## Recommended polling intervals

| Compression type | Poll interval |
|-----------------|---------------|
| Images (JPG, PNG, GIF) | 1-2 seconds |
| Universal image ({{universal-format-count}}+ formats) | 2-3 seconds |
| PDF documents | 3-5 seconds |
| Office documents (DOCX, PPTX) | 3-5 seconds |
| Large files (> 50 MB) | 5-10 seconds |

## Best practices

1. **Respect `Retry-After`** — wait the indicated seconds before retrying.
2. **Exponential backoff** — if no `Retry-After` header, back off: 1s, 2s, 4s, 8s, max 30s.
3. **Poll, don't spin** — use the intervals above instead of tight loops.

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