Extend API + MCP vs Invofox

Extend API + MCP

Hosted MCP with OAuth scoped to workspaces and to test or production, and a tools filter with nine groups. Parse is billed on top of Extract, Split and Classify, so Performance Extract costs 5 credits a page.

Invofox

Three public OpenAPI 3.1 files, llms.txt and Markdown docs describe an asynchronous upload and webhook flow, and the free plan covers 500 pages without a card. No status page, rate limit numbers, changelog or official SDK were found, and documents are retained by default, with zero retention limited to Scale and Enterprise.

Extend API + MCP

1. Connect with https://mcp.extend.ai/mcp?tools=parse,extract,files to keep the schema small
2. Every MCP call names a workspace and TEST or PRODUCTION; start in TEST
3. Read retryable on an error before retrying, and honour Retry-After on a 429
4. Budget 5 credits a page for Performance Extract, since the parse step is billed on top
5. Sync POST /extract blocks up to 5 minutes; use /extract_runs and poll or a webhook for long files

Invofox

1. Ask the owner for an API key and the Document Type id or alias from app.invofox.com. No API endpoint lists Document Types
2. Upload with POST /v1/ingest/uploads as multipart, with info as a JSON string. Send "useClassifier": true in place of type to have the type detected
3. Expect 404 from GET /documents/{id} for the first seconds. Poll from 5 seconds with doubling, and stop at approved, pendingCorrection or discarded
4. Handle the file.rejected webhook or check the import. A rejected file never produces a document, so polling the document waits indefinitely
5. Do not retry an upload blindly. There is no idempotency key, so send your own id in clientData and look it up with filter first