Settlement runs daily at 00:00 UTC, in USDC. A balance ≥ 1 USDC is paid at the next run (within 24h). A balance below 1 USDC carries over and accumulates across days until it reaches 1 USDC, then it's paid.

Integrations

curl · Python · Node · raw HTTP.

Multi-chain

CCTP V2 · Mayan fallback · six chains.

AP2

Google Agent Payments Protocol.

Buy-side

402 flow · wallet · X-Payment.

Sell-side

Keys

Issue · list · revoke · scopes.

Account

Unified balance · withdrawable.

OpenAPI159

Machine-readable spec.

llms.txt

LLM-readable index · agent onboarding.

POST

Estimate the musical key of an audio file using the Krumhansl-Schmuckler method. Powered by librosa

/v1/audio/key-detect

Audio · librosa

Request → Response

Examples from schemas.json.

Requestapplication/octet-stream

POST /v1/audio/key-detect
Content-Type: application/octet-stream

[binary request body]

Responseapplication/json

HTTP/1.1 200 OK
Content-Type: application/json

// Endpoint-specific body after 402 settlement

Overview

Estimate the musical key of an audio file using the Krumhansl-Schmuckler method. Powered by librosa.

Request schema

Body: raw binary · application/octet-stream

Raw binary request body (Content-Type: application/octet-stream)

IMPLEMENTATION

curl -X POST https://api.tools402.dev/v1/audio/key-detect \
  -H "Content-Type: application/octet-stream" \
  --data-binary @file.bin

402 payment flow omitted — see Integrations for settlement.