How to Add Cross-Chain Swaps to a Go Microservice

Go powers the backends of most major blockchain infrastructure -- from consensus clients to validator tooling to DEX routing engines. If you need to add token swaps across multiple EVM chains to a Go service, you can do it with a single GET request and zero API keys. This guide walks through building a production-ready swap client in Go using swapapi.dev, a free DEX aggregator API that covers 46 chains. Cross-chain swap volume hit $56.1 billion in a single month in mid-2025, and the DeFi market is projected to grow at a 43.3% CAGR through 2030. If your Go service touches crypto, swap functionality is table stakes. What You'll Need Before writing any code, make sure you have: Go 1.21+ installed (go version) A wallet address to use as the sender parameter (the address that will execute the swap on-chain) Basic familiarity with EVM token standards (ERC-20 addresses, decimals, raw amounts) No API key -- swapapi.dev requires zero authentication The API is a single endpoint: GET /v1/swap/{ch