Yonatan Valencia

Colombian payroll law as a dated, verifiable catalog — plus the engine that applies it

A deterministic payroll and withholding-tax engine built on a dated legal catalog: every statutory parameter — minimum wage, transport allowance, UVT, night and Sunday premiums, the ordinary-hour divisor, social security rates, garnishment and withholding caps — resolves on any date since 2020, each carrying the decree or resolution that set it and the window it was in force. Five calculators sit on top of it (payroll, withholding tax, payslip verification, final settlement, USDC payout). Stateless by design: request payloads are computed in memory and never written to a database, per Colombia's habeas data law. Built as a pnpm monorepo — Express + Prisma + TypeScript API, React 19 + Vite front end, a shared rules package — with CI typechecking and testing all three workspaces on every push.

• Signed results. Every response cites its legal basis, carries the SHA-256 of the catalog that produced it and is signed with Ed25519, so a third party can verify it offline without trusting the issuer. The signing format is an open CC0 spec — the sobre — with a frozen canonicalization, published test vectors and a conformance suite that any new implementation can run against: Ruby, Node and the browser already produce byte-identical signatures, and the spec includes a section on what a signature does not assert.
• Machine-payable API (x402). Priced endpoints answer HTTP 402 with an on-chain payment requirement and serve only once the transfer settles — USDC via EIP-3009 on Base and Avalanche, each network routed to its own facilitator, and the server refuses to boot if a network is routed to one that cannot settle it. Charge-before-serve is enforced at the wall, not in the handler.
• Free triage, priced report. A free precheck endpoint runs the same engine and tells you upfront whether a payslip is clean, at no cost — you only pay for the full report, and pricing never depends on what it finds.
• Agent commerce. ERC-8004 identity #59771 on Base mainnet, an A2A agent card and an ARD catalog for federated discovery — all served by a single Cloudflare Worker, with the AI-usage policy pinned to IPFS and attested by digest. Requests to Execution Market are signed with ERC-8128, and the service is listed and sold there agent-to-agent, with delivery returned inline and signed. An MCP server gives any agent five tools to discover, verify and buy — including a cross-check of the payment address in the live 402 against the published agent card, so an intercepted wall cannot silently redirect funds.
• Documentation that is audited, not trusted. Each published constant has exactly one place where it is asserted; auditors sweep the whole tree, compare it against the chain and against what the servers actually return, and fail when prose drifts from reality.

Verify a signed result yourself — no signup, no install, nothing to pay. One URL carries everything: the page fetches the live sample from the API and checks its signature in your browser:
ynt.codes/verificar?url=https://nomicheck.ynt.codes/api/batch/verificar/ejemplo
…or open the raw signed sample straight from the API:
nomicheck.ynt.codes/api/batch/verificar/ejemplo