Rate Limits

Credit model

PDFBase uses a simple credit-based billing model:

1 credit = 1 output PDF (or image, or extraction result).
Failed requests = 0 credits. You only pay for successful outputs.
Batch of N items = N credits. A batch request that produces 50 PDFs costs 50 credits.

Specific rate limits and pricing tiers will be finalized at launch. The mechanics below (headers, concurrency, size limits) are stable.

Rate limit headers

Every response includes headers showing your current usage:

X-RateLimit-Limit: 300
X-RateLimit-Remaining: 287
X-RateLimit-Reset: 1716120000
X-RateLimit-Concurrent: 3
X-RateLimit-Concurrent-Limit: 20

Header	Description
`X-RateLimit-Limit`	Max requests per minute for your plan
`X-RateLimit-Remaining`	Requests remaining in the current window
`X-RateLimit-Reset`	Unix timestamp when the window resets
`X-RateLimit-Concurrent`	Active concurrent renders right now
`X-RateLimit-Concurrent-Limit`	Max concurrent renders for your plan

When you hit a limit

A 429 response includes a Retry-After header (in seconds):

HTTP/1.1 429 Too Many Requests
Retry-After: 3
X-RateLimit-Limit: 60
X-RateLimit-Remaining: 0
X-RateLimit-Reset: 1716120003

{
  "error": {
    "type": "rate_limit_error",
    "code": "too_many_requests",
    "message": "Rate limit exceeded. Retry after 3 seconds.",
    "param": null
  }
}

Ignoring Retry-After and hammering the API will result in progressively longer cooldowns. Respect the header.

Concurrency limits

PDF rendering is resource-intensive. Your plan has a cap on how many PDFs can be rendered simultaneously. If all slots are occupied, new requests queue for up to 30 seconds before returning 429. This is separate from the per-minute rate limit. You can be within your request limit but at your concurrency cap.

How to stay under concurrency limits

Use batch endpoints for bulk operations. One batch request uses one concurrency slot regardless of item count.
Use output: "url" instead of output: "base64" — URL mode frees the rendering slot as soon as the file is written to storage.
Set reasonable timeouts. A stuck page (waiting for a broken asset) holds a slot. Use resource_timeout to cap it.

Size limits

Resource	Limit
HTML body	10 MB
Template HTML	5 MB
Uploaded file (for merge/watermark)	50 MB
Batch items	2,000
Request body (total)	50 MB
Generated PDF	100 MB

Exceeding size limits returns 413:

{
  "error": {
    "type": "invalid_request",
    "code": "html_too_large",
    "message": "HTML body exceeds the 10MB limit. Current size: 12.4MB.",
    "param": "html"
  }
}

Timeout limits

Operation	Default timeout	Maximum
HTML-to-PDF render	30s	120s
Template render	30s	120s
Merge/split/watermark	60s	300s
Office-to-PDF conversion	60s	300s
OCR extraction	120s	600s
Batch job (total)	30min	2hr

Pass timeout in the request to override the default (up to the maximum):

{
  "html": "<h1>Complex report</h1>...",
  "timeout": 60000
}

Get Started

Core Concepts

Guides

Integrations

Resources

Credit model

Rate limit headers

When you hit a limit

Concurrency limits

How to stay under concurrency limits

Size limits

Timeout limits

​Credit model

​Rate limit headers

​When you hit a limit

​Concurrency limits

​How to stay under concurrency limits

​Size limits

​Timeout limits

Credit model

Rate limit headers

When you hit a limit

Concurrency limits

How to stay under concurrency limits

Size limits

Timeout limits