FixedFloat API — instant crypto swaps for your product
Embed instant cryptocurrency exchange into wallets, payment processors, Telegram bots or trading desks. The FF API exposes the same engine that powers ff-io.io — rates, order creation, status, history and refunds — over a clean REST interface.
REST + JSON
Simple, predictable HTTPS endpoints. No proprietary SDK required.
HMAC auth
HMAC-SHA-256 request signing keeps your API key safe in transit.
Webhooks
Optional webhooks notify your server of every status change in real time.
Endpoint overview
The FixedFloat API is structured around the same workflow as the public widget: get a price, create an order, send the deposit, watch the status, fetch the result.
| Endpoint | Method | Purpose |
|---|---|---|
| /api/v2/ccies | GET | List supported currencies and chains |
| /api/v2/price | POST | Get a quote for a pair |
| /api/v2/create | POST | Create an exchange order |
| /api/v2/order | POST | Get the status of an order |
| /api/v2/emergency | POST | Set a refund address |
| /api/v2/qr | GET | QR code for a deposit address |
Sample request
A minimal example of creating a fixed-rate BTC → ETH order.
curl https://ff-io.io/api/v2/create \
-H "X-API-KEY: your_key" \
-H "X-API-SIGN: hmac_sha256_signature" \
-H "Content-Type: application/json" \
-d '{
"type": "fixed",
"fromCcy": "BTC",
"toCcy": "ETH",
"amount": "0.5",
"toAddress": "0x83a..."
}'
What you can build
- Wallet swaps. Add a "convert" button inside a non-custodial wallet that routes through the FixedFloat hot wallet behind the scenes.
- Telegram and Discord bots. Build community swap bots that offer instant pricing and trade execution.
- Payment processors. Let merchants accept BTC and settle in USDT automatically — the API handles the conversion in real time.
- Trading dashboards. Expose the FF rate alongside other venues for arbitrage detection.
- Affiliate apps. Combine the API with the FixedFloat affiliate programme to earn revenue share on every swap your users make.
Rate limits and uptime
Default rate limits are generous — 60 requests per minute per key for read endpoints, 30 per minute for write endpoints. Higher tiers are available on request. Public uptime is monitored at status.ff-io.io and historically tracks above 99.9%.
Pricing
The FixedFloat API uses the same fee schedule as the public widget — from 0.5% per swap, plus the on-chain network fee. There is no separate API subscription fee. Affiliates earn revenue share on top.