# Melchior Video Context API

> Pay-per-request YouTube caption extraction, lexical evidence search, and transcript normalization for autonomous agents.

Base URL: https://transcript.melchiorlabs.com
OpenAPI: https://transcript.melchiorlabs.com/openapi.json
Discovery: https://transcript.melchiorlabs.com/.well-known/x402
Payment: x402 v2, Base or Solana mainnet USDC, no account or API key

## Paid resources

- POST https://transcript.melchiorlabs.com/v1/youtube/transcript — $0.01 after a successful response. Send JSON with a public YouTube `url`; optional fields include `language`, `preferManual`, `maxChunkCharacters`, `includeSegments`, and `includeText`.
- POST https://transcript.melchiorlabs.com/v1/youtube/search — $0.005 after a successful response. Send a public YouTube `url` and `query`; optional `maxResults` and `contextSegments` control the compact, timestamp-cited matches. This is deterministic lexical phrase and term matching, not semantic search. A valid no-match search returns an empty `matches` array. Also available as GET on the same path with the same fields as query parameters, same price, and same validation, e.g. `GET https://transcript.melchiorlabs.com/v1/youtube/search?url=...&query=...`.
- POST https://transcript.melchiorlabs.com/v1/transcripts/context — $0.003 after a successful response. Send transcript `text`, WebVTT, SRT, or timestamped `segments` and receive normalized, model-sized chunks.

An unpaid request returns HTTP 402 with a machine-readable PAYMENT-REQUIRED header. Retry with the x402 payment signature. Failed video extraction is not settled. Responses include timestamped segments, chunks, and source deep links suitable for citation.

## TypeScript paid quickstart

Install @x402/core, @x402/fetch, @x402/evm, and viem. Register an ExactEvmScheme for eip155:8453 with an EVM signer, wrap the native fetch function with wrapFetchWithPayment, and POST the request body normally. The client handles the HTTP 402 quote, payment signature, and retry. A complete copyable example is published on https://transcript.melchiorlabs.com/#paid-quickstart. Official buyer documentation: https://docs.x402.org/getting-started/quickstart-for-buyers

## Free resources

- GET https://transcript.melchiorlabs.com/openapi.json — complete OpenAPI 3.1 schema and payment metadata.
- GET https://transcript.melchiorlabs.com/v1/health — service and extractor health.