Errors

Errors return the matching HTTP status and a JSON body of the shape { "error": { "code", "message" } }. Branch on the stable code rather than the human-readable message.

Status	Code	Meaning
`401`	`missing_api_key`	No API key was provided.
`401`	`invalid_api_key`	The key is invalid or revoked.
`402`	`quota_exceeded`	Monthly PDF quota reached — upgrade your plan.
`404`	`template_not_found`	No template with that id exists for your account.
`429`	`rate_limited`	Too many requests — retry after the Retry-After delay.
`422`	`invalid_json`	The request body was not valid JSON.
`422`	`missing_template_id`	The 'template_id' field is required.
`422`	`data_too_large`	The 'data' payload exceeds 256 KB.
`422`	`template_compile_error`	The template has a syntax error.
`422`	`template_render_error`	The template failed to render with this data.
`502`	`render_failed`	The render service returned an error.
`504`	`render_timeout`	Rendering took longer than 20 seconds.

402, 429, 502 and 504 are safe to retry with backoff — for 429, wait for the Retry-After header; 4xx validation errors are not — fix the request first.

Every /v1/generate response includes X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset so you can pace requests before hitting a 429.