API Reference

Use the StartOCR HTTP API to submit images and PDFs from your own applications.

Authentication

Create an API key from Settings in your account (sign in first). Send it as a Bearer token on every request:

Authorization: Bearer YOUR_API_KEY

Copy your key when it is created — it is shown only once. Revoke compromised keys from Settings.

Submit a job

POST https://startocr.com/api/ocr
Content-Type: application/json

Request body

Field	Type	Required	Description
`imageBase64`	string	Yes	Base64-encoded file bytes, or a `data:image/...;base64,...` data URI
`filename`	string	No	Original filename (used for type detection)
`provider`	`"paddle"` \| `"baidu"`	No	OCR engine. Defaults to `"paddle"`

Example

curl -X POST https://startocr.com/api/ocr \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "imageBase64": "data:image/png;base64,iVBORw0KGgo...",
    "filename": "scan.png",
    "provider": "paddle"
  }'

Success response

{
  "success": true,
  "taskId": "clx...",
  "provider": "paddle"
}

Save the taskId — use it to poll task status in the dashboard or via your account's task APIs.

Error responses

HTTP	`error` code	Meaning
401	`missing_api_key`	No `Authorization: Bearer` header
401	`invalid_api_key`	Key is invalid or revoked
400	`missing_image_base64`	Request body missing `imageBase64`
400	`invalid_image_base64`	Could not decode the payload
402	`insufficient_pages`	Account has no remaining page balance
413	`payload_too_large`	Request body exceeds 10 MB
415	`unsupported_media_type`	`Content-Type` must be `application/json`

Providers

paddle (default) — file is queued for async processing. Poll until the task reaches done.
baidu — synchronous OCR with word-level positions. Result is stored when the request completes.

Billing

Each submission deducts pages based on the document's page count before processing starts. If task creation fails after deduction, pages are refunded automatically.

CORS

Browser-based calls must originate from an allowed domain. Server-to-server integrations do not require CORS configuration.