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

Recommended polling intervals

Conversion type	Poll interval
Images (HEIC, PNG, JPG, WebP, AVIF)	1-2 seconds
Documents (PDF, DOCX, PPTX)	3-5 seconds
Audio transcription	5-10 seconds
Large files (> 50 MB)	5-10 seconds

URL fetch limits

When using URL input, additional limits apply:

Limit	Value	Description
Concurrent fetches	3 per account	Maximum simultaneous URL fetches. Exceeding returns `url_fetch.rate_limited` (429)
Domain circuit breaker	5 failures / 60s	After 5 fetch failures to the same domain within 60 seconds, that domain is blocked for 60 seconds. Returns `url_fetch.domain_circuit_open` (400)
HTTPS only	Production	HTTP URLs are rejected in production with `url_fetch.invalid_scheme`. HTTP is allowed in development only
Max redirects	3	Each redirect hop is re-validated against SSRF rules

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.

Models Reference

List Conversions

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

## Recommended polling intervals

| Conversion type | Poll interval |
|----------------|---------------|
| Images (HEIC, PNG, JPG, WebP, AVIF) | 1-2 seconds |
| Documents (PDF, DOCX, PPTX) | 3-5 seconds |
| Audio transcription | 5-10 seconds |
| Large files (> 50 MB) | 5-10 seconds |

## URL fetch limits

When using [URL input](endpoints/convert.md#url-input-applicationjson), additional limits apply:

| Limit | Value | Description |
|-------|-------|-------------|
| Concurrent fetches | 3 per account | Maximum simultaneous URL fetches. Exceeding returns `url_fetch.rate_limited` (429) |
| Domain circuit breaker | 5 failures / 60s | After 5 fetch failures to the same domain within 60 seconds, that domain is blocked for 60 seconds. Returns `url_fetch.domain_circuit_open` (400) |
| HTTPS only | Production | HTTP URLs are rejected in production with `url_fetch.invalid_scheme`. HTTP is allowed in development only |
| Max redirects | 3 | Each redirect hop is re-validated against SSRF rules |

## 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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