x402-global-challenge

FabTally Algo — on-chain decoder, paid on Algorand mainnet

This endpoint decodes a raw EVM 4-byte function selector or 32-byte event topic hash into its human-readable signature(s) — real work, not a mock. Payment is USDC on Algorand mainnet, settled via the GoPlausible x402 facilitator, using the x402 protocol (HTTP 402 Payment Required, exact scheme).

$0.001 USDC per call

How to pay

Any x402-aware client can call this. Without payment you get a 402 challenge with the exact Algorand payment requirements (asset id, amount, receiving address). Attach a signed Algorand payment (an atomic transaction group carrying a USDC asset transfer) in the X-PAYMENT header and retry — the facilitator verifies and settles it on-chain, then you get your result.

Try it (no payment — see the 402 challenge)

curl -s -i -X POST https://algo.fabtally.com/v1/selector-lookup \
  -H 'content-type: application/json' \
  -d '{"selector":"0xa9059cbb"}'

Full paid flow

See test_client.mjs in the project repo for a runnable end-to-end example using @x402/fetch + @x402/avm.

Discovery

• /agent/overview — machine-readable capabilities + pricing (free)
• /.well-known/x402 — x402 discovery document (free)
• /health — health check (free)

About

FabTally is a per-call API business (fabtally.com) selling manufacturing and blockchain-developer utilities to AI agents and developers, operated by Sunstone Soft. This Algorand rail is a parallel deployment built for the Algorand Global x402 Challenge (tag: x402-global-challenge) — the existing Base-mainnet product (decode.fabtally.com) is unmodified.