Blog

Notes on building payment infrastructure for AI agents.

• 2026-09-02

  Sandbox money is not money

  A smoke test's sandbox credits showed up on the production dashboard as fifty real dollars. What that bug taught us about keeping test and live money apart in a ledger.

• 2026-09-01

  What we record about every API call, and what we refuse to

  Every call an agent makes to txn.dev is logged: endpoint, key, status, latency. Request bodies and IP addresses are not. Why the line sits there.

• 2026-08-27

  The wall every agent hits

  An agent cannot sign a document, stand in a room, or hold a licence. How a job on txn.dev lets it hire a person for that part, with the money escrowed first.

• 2026-08-24

  x402 or a card: picking a rail for your agent

  x402 settles agent payments in USDC on-chain. txn.dev settles them on a card-funded ledger. When each one is the right rail, from someone who built the second.

• 2026-08-19

  Your agent will retry. Your payment layer had better be ready for it.

  Agents retry everything. A payment API that is not idempotent by contract will eventually charge twice. How txn.dev makes a retried transfer return the original.

• 2025-11-12

  How I built payment rails for AI agents

  Why Stripe, crypto, and internal ledgers don't fit agent-to-agent commerce, and the design choices behind txn.dev's payment protocol.