API Reference

This page lists the supported public integration operations. The machine-readable source is OpenAPI 3.1.

Base URL

https://api.coinssend.com/v1/

Authentication

For detailed authentication information, see Authentication.

Headers

Header	Description
Content-Type	Must be application/json for all requests
Merchant	Your merchant ID (required for authenticated endpoints)
Sign	Request signature (required for authenticated endpoints)
Timestamp	Unix timestamp in seconds. Required for POST /v1/withdrawals; optional only when using timestamped HMAC on other merchant endpoints.

Endpoints Summary

Method	Path	Description	Authentication
POST	/v1/invoices	Create a new invoice	Merchant + Sign
POST	/v1/withdrawals	Initiate a withdrawal	Merchant + Timestamp + Sign
GET	/v1/merchants/balances	Get merchant balances	Merchant + Sign
GET	/v1/merchants/fees	Get merchant fees	Merchant + Sign
POST	/v1/wallet-address	Create static wallet address	Merchant + Sign
GET	/v1/get-coin-rate	Get current USD exchange rates for supported assets	None
GET	/v1/coins-and-fee	Get the current supported coin/network catalog with fee metadata	None
GET	/v1/invoices/{invoiceCode}	Get public invoice checkout state	None
POST	/v1/invoices/{invoiceCode}/provider-card-orders	Start or reuse active card checkout	None
GET	/v1/wallet-addresses/{walletId}/qr	Render the QR URL returned by wallet/invoice responses	None

Detailed API Documentation

Invoices

• Create Invoice
• Get Invoice
• Create Provider-Card Order

Withdrawals

• Initiate Withdrawal

Merchants

• Get Merchant Balances
• Get Merchant Fees

Static Wallets

• Create Wallet Address

Supported Coins, Networks & Rates

• Supported Coins & Networks
• Get Coin Rates
• Get Supported Coins & Fee

Supported Coins & Networks

Browse the coin and network tables for display names, API identifiers, and guidance on building payment selectors.

Use GET /v1/coins-and-fee for live discovery instead of copying a static coin or network list into an integration. Availability, limits, fees, and precision can change without an API schema change. Individual write endpoints remain the final authority for accepting a pair; the catalog is not an offline validation guarantee. See Coin Rates.

Webhooks

• Webhook Events
• Webhook Authentication

Common Response Formats

Most operations use the following success envelope:

Success Response

{
  "status": "success",
  "data": {
    // Response data specific to the endpoint
  }
}

Endpoint Error Response

{
  "status": "error",
  "message": "Error description"
}

Some errors include additional fields (for example, fee breakdowns) alongside status and message. Authentication errors may instead return {"error": "Reason"} without the status field. Always rely on the HTTP status code first.

Validation failures use HTTP 422 with errors, status, and message. Symbolic labels shown in prose are not guaranteed response fields.

Response Data Types

The following data types are used throughout API responses:

Type	Description	Example
string	Text values	"example"
integer	Whole numbers	42
float	Numbers with decimals	10.5
boolean	true or false values	true
array	Ordered list of values	[1, 2, 3]
object	JSON object containing key/value pairs	{ "key": "value" }

Amount Precision

All monetary amounts, percentage values, and currency rates in API responses are returned as strings. Using strings preserves accuracy for values with many decimals. Request parameters should also be sent as strings containing numeric values.

Common HTTP Error Responses

HTTP Code	Description
400	Bad Request - The request was invalid or cannot be served
401	Unauthorized - Authentication credentials are missing or invalid
403	Forbidden - The request is understood, but it has been refused
404	Not Found - The requested resource does not exist
422	Unprocessable Entity - The request was well-formed but could not be processed
429	Too Many Requests - Rate limit exceeded
500	Server Error - Something went wrong on our end

Rate Limits

The only merchant-public write limit verified in this application is the wallet-creation limit: 100 successful creations per merchant in a 60-second window. Additional limits may apply. See Rate Limits.

Versioning

The API is versioned in the URL path (/v1/). When breaking changes are introduced, a new version number will be used.