API General

Base URL: https://api.fonproxy.io

Authentication

All protected endpoints require an API key:

Generate an API key in your account: API Keys.

Locale

The API uses the fp-locale header to determine the user's language.

fp-locale: uk

Behaviour

• Every request: the backend reads fp-locale and uses it for server-rendered content (emails, Telegram notifications).
• Logged-in users: if the header value differs from the stored locale, the backend automatically updates the user's locale in the database (fire-and-forget, no extra request needed).
• Supported locales: en (English, default), uk (Ukrainian).
• Get current locale list at runtime: GET /locales
• Fallback: if the header is missing or the locale is unknown, en is used.

What Gets Translated

The locale field is always returned in the user profile (GET /user/me) so the frontend can initialise its own i18n accordingly.

Common Headers

Response Format

All responses are JSON. Success responses return the relevant data directly:

{
  "user": { "id": "k5Xz9qR2Wp", "name": "John", ... }
}

Error responses:

{
  "message": "order.not_found",
  "path": "/orders/80-12345",
  "timestamp": "2026-04-01T12:00:00.000Z"
}

The message field is a translation key — the frontend resolves it to a human-readable string.

Pagination

Paginated endpoints accept:

Response includes:

{
  "items": [ ... ],
  "total": 142,
  "page": 1,
  "pages": 8
}

Currency

• All prices and balances are stored in USD internally.
• Display values are converted using live exchange rates.
• The user's preferred display currency is set via PATCH /user/settings { "currency": "UAH" }.
• Endpoints that return monetary values include both *Usd and *Display fields.

Rate Limiting

Throttled by IP address. Default: 60 requests / minute for most endpoints, 5 / minute for auth endpoints.

When rate-limited, the API returns 429 Too Many Requests:

{ "message": "error.rate_limit" }

Locales

GET /locales

Returns all currently supported locale codes with their display names.

Response:

{
  "locales": [
    { "code": "en", "name": "English", "nativeName": "English" },
    { "code": "uk", "name": "Ukrainian", "nativeName": "Українська" }
  ]
}

Currency

GET /currencies

Returns all supported currency codes. Public, no authentication required.

Response:

{
  "currencies": ["USD", "EUR", "GBP", "PLN", "CZK", "HUF", "RON", "SEK", "NOK", "DKK", "CHF", "HRK", "BGN", "UAH", "TRY"]
}

GET /currencies/rates

Returns the latest exchange rates keyed by currency code. Each value is "1 base = N target" — with base=USD, "EUR": 0.92 means 1 USD buys 0.92 EUR. Public, no authentication required.

Query Parameters

Response:

{
  "base": "USD",
  "rates": {
    "USD": 1,
    "EUR": 0.92,
    "UAH": 41.2,
    ...
  }
}

Errors:

API Reference

Public

Admin