Unter Payment Gateway

Accept cryptocurrency payments from any chain, any token. A single API integration handles cross-chain swaps, wallet detection, and settlement.

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Why Unter?

Multi-Chain Support

Accept payments from Ethereum, Polygon, Base, BSC, Solana, TRON, and more. Customers pay with any token they hold.

Cross-Chain Swaps

Automatic routing via aggregators. Customers can pay with ETH on Ethereum while you receive USDC on Polygon.

Simple API

Create a payment request with one POST call. Redirect the customer to the hosted checkout page. Receive a webhook when paid.

Secure by Default

HMAC-SHA256 signed webhooks, bcrypt-hashed API keys, rate limiting, CORS restrictions, and replay protection.

Quick Overview

How it works in 3 steps 1. Create a payment request via the API
2. Redirect your customer to the hosted checkout
3. Receive a webhook when payment is confirmed

Documentation Sections

Quick Start Guide

Step-by-step integration guide with curl examples. Get your first payment request running in minutes.

API Reference

Complete endpoint reference for public and authenticated APIs. Includes methods, paths, authentication, and permissions.

Payment Lifecycle

Understand the full payment flow from creation to settlement, including cross-chain routing and status transitions.

Webhook Integration

Set up webhook receivers, verify signatures, and handle events. Includes code examples in PHP, Node.js, and Python.

Environments

Service Staging Production
API https://api-staging.unter.tech https://api.unter.tech
Checkout Widget https://cdn-staging.unter.tech https://cdn.unter.tech
API Docs (Swagger) /api/doc /api/doc
Tip Use the staging environment for integration testing. Switch to production for live payments.

Powered by Unter.tech — Crypto payment infrastructure