Sera FX delivers real-time buy, sell and mid-market rates across 160+ currencies through one clean API. No credit card. No paid tier. No catch.
The reliability of an enterprise feed, without the enterprise invoice.
Rates updated every minute from aggregated interbank and market-maker feeds — not once-a-day snapshots.
Full two-way quotes on every pair, so you price real conversions instead of showing a reference rate.
Every major and most minor currencies, plus common crosses. One base, any target, both directions.
Query any rate back through years of history for backtesting, reporting and reconciliation — also free.
Sign up, get a key, start calling. There's no upgrade page because there's nothing to upgrade to.
Predictable responses with official libraries for JavaScript, Python, PHP and Go. Copy, paste, ship.
Most APIs hand you a mid rate and call it done. Sera FX returns buy, sell and mid — so the number your users see is the number they actually get. Play with it →
A rates hub in the spirit of the classics — charts, spreads and a full board — except the data is open and the settlement is on-chain.
Pick any base and quote currency, or hit ⇄ to flip the pair · rates from Sera's on-chain settlement engine
Enterprise feeds start in the thousands per month. Everyone below that line has been stuck with stale, hobbled free tiers. Not anymore.
Purpose-built for autonomous finance — LLM apps, trading copilots, and payment agents that need trustworthy FX at inference time. MCP + OpenAPI native.
Ship a converter, invoicing tool or dashboard without a rate-data invoice. No card, no gatekeeping.
Full history for backtests, theses and coursework. Query years of rates, free, no scraping.
Remittance, treasury and payments MVPs — prototype on the same rates the settlement engine runs on.
Every quote Sera FX returns is a price the network can actually clear. When you're ready to move value, route the same conversion through Sera's on-chain settlement engine: 600+ stablecoins, 120+ currencies, non-custodial, in seconds.
Sera runs the on-chain FX settlement engine for stablecoins — routing 600+ stablecoins across 120+ currencies, non-custodial and audited by CertiK. Every cross-border payment that clears through Sera is priced, in real time, by that engine.
Exposing those prices as a public API costs us nothing extra. And it helps the builders — remittance apps, fintechs, and AI agents — who send real flow back through the protocol. Sera earns from the FX spread on settlement, never from selling data. So the data stays free, forever.
Built and run by the team behind the on-chain FX settlement engine. Rates sourced from Sera's live CLOB — both sides quoted at market.
The settlement protocol powering these rates is audited by CertiK. No custody, no counterparty, atomic on-chain fills.
Full REST reference at docs.sera.cx. Client SDKs are open source and community-maintained.
MCP server and OpenAPI 3 spec live at agents.sera.cx — quote and settle programmatically.
What you'd pay a legacy provider for — and what Sera FX gives away.
REST, JSON, and a key you get in ten seconds. Base URL https://api.sera.cx/v1
Yes, fully free with no paid tier. Sera runs the on-chain FX settlement engine and earns from the spread on real payment flow, not from selling data. Opening the rates costs us nothing extra and brings builders into the ecosystem.
No. Sign up, get an API key, and start calling. No card, no sales call, no KYC to read rates.
It's built for it. Beyond the REST API, Sera exposes an MCP server and OpenAPI 3 spec at agents.sera.cx, so LLM apps, copilots and autonomous payment agents can quote and settle programmatically with trustworthy FX at inference time.
Yes. Commercial use is allowed. Attribution terms depend on the license you build under — the SDKs are permissively licensed and the rate data carries a simple attribution requirement.
The rates aren't a static feed — they're live prices from Sera's settlement engine. So the same quote you read can be cleared on-chain across 600+ stablecoins and 120+ currencies, non-custodial, in seconds.
Free key, no card, no limits to worry about. Just accurate FX where you need it.
Get started free →