Playground

Toys built from the same primitives as production.

Everything below runs entirely in your browser and computes real values — real HMAC/SHA-256 signatures, a real backoff+jitter curve, a real ISO 8583 field parser. Nothing here is decorative.

Webhook Signature Workbench

Paste a payload, pick a signing scheme — HMAC-SHA256, checksum, or JWT — and watch the exact signature a merchant integration would compute and verify.

HMACJWTChecksum

Retry Ladder Simulator

Tune failure rate and latency for a downstream partner and watch exponential backoff, jitter, and a circuit breaker trip in real time — the same shape as production peon retries.

BackoffCircuit breakerResilience4j

ISO 8583 Decoder

Paste a raw ISO 8583 message and see it exploded into labelled fields — MTI, bitmap, PAN, amount — the same protocol powering national financial switches.

jPOSFinancial messaging