Hey Product Hunt 👋 Solo dev here. I built ChronoShield because I kept hitting the same class of bug in every project: code that "works" all year then silently breaks for an hour on DST transition day. What it does — four endpoints: • /validate — is this local datetime real in this zone? (catches DST gaps) • /resolve — given an ambiguous or invalid datetime, what UTC instant does it map to? (configurable policy) • /convert — UTC → any target zone • /version — which IANA tzdata release am I serving? (surprisingly useful) Handles the fun stuff: spring-forward gaps, fall-back overlaps, non-whole-hour offsets (Kathmandu +5:45, Chatham +12:45), 30-minute DST shifts (Lord Howe), historical zone rules, and recent legislative changes (BC's permanent-DST law is live in our data as of IANA 2026b). What I'm proudest of (technically): I just shipped a refactor that decouples tzdata from the Node.js runtime version. Most APIs in this space are stuck on whatever tzdata their runtime ships with. ChronoShield can ship new IANA releases the same week they drop — no Node bump needed. SDKs published yesterday: • npm install chronoshield • pip install chronoshield Pricing: • Free: 1k req/mo (no card) • Pro: $19/mo for 100k req • Enterprise: custom I built this entirely solo, on nights and weekends. Today's launch is the start, not the finish — would genuinely love feedback on what's missing, what's confusing, or what you'd want next. Happy to answer anything about the stack (Fastify/TS/Postgres/Railway), the tzdb decouple architecture, the parity test harness (~30k zone×timestamp checks gate every deploy), or the weirdest DST rules I've found. → chronoshieldapi.com

ChronoShield API

A REST API that catches timezone bugs before they ship

A REST API that catches timezone bugs before they ship