eth-backend

A Go backend project focused on Ethereum data access, event parsing, and transfer indexing.

This project was built to explore how to connect a backend service to blockchain data, process on-chain events, and expose useful APIs for querying account and transaction information. It combines backend development, database design, caching, and background processing in a single full-stack-style service.

Project highlights

• Built a REST API service in Go to query Ethereum account, block, transaction, and receipt data
• Parsed ERC-20 transfer and approval events from transaction logs
• Implemented a background listener to continuously scan new blocks and index transfer activity
• Stored indexed transfer records in PostgreSQL for structured retrieval and analysis
• Used Redis to cache transfer query results and improve read performance
• Added health checks, logging, and metrics to improve service observability

What I learned / demonstrated

This project demonstrates practical experience in:

• Backend service development with Go and Gin
• Integrating with external blockchain RPC APIs using go-ethereum
• Designing data flow between application, database, and cache
• Handling asynchronous background processing for real-time data ingestion
• Building services with basic production-minded concerns such as monitoring and reliability

Tech stack

• Go
• Gin
• go-ethereum
• PostgreSQL
• Redis
• Docker Compose
• Kubernetes
• Prometheus / health monitoring

API overview

The service exposes several REST endpoints for blockchain data access and transfer history:

• GET /balance?address=<ETH_ADDRESS>
  • Returns the ETH balance for a given wallet address
• GET /block
  • Returns the latest block number
• GET /tx?hash=<TX_HASH>
  • Returns transaction information by hash
• GET /receipt?hash=<TX_HASH>
  • Returns transaction receipt details
• GET /tx/detail?hash=<TX_HASH>
  • Returns transaction details along with parsed logs and transfer information
• GET /transfers?address=<ETH_ADDRESS>&page=1&page_size=20
  • Returns indexed transfer records associated with the given address

Deployment

The project is prepared for containerized deployment and includes Kubernetes manifests under the k8s folder for:

• application deployment
• PostgreSQL
• Redis
• Prometheus
• Grafana

Test

The project used mockery for interface testing, the interface is under internal/listener/interface.go. The command is just mockery and used the configuration file in root dic, named .mockery.yml