Mainnet S0
Mainnet JSON-RPC
https://harmony-mainnet-s0.gateway.tatum.io
Free Harmony RPC (ONE)
Discover Harmony, a blockchain optimized for scalability and low-latency transactions. Build high-performance dApps using its RPC gateway.
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RPC Gateway
Connect to Harmony RPC
Access reliable, enterprise-grade RPC endpoints that power your dApp with ultra-low latency and 99.9% uptime.
Connect to Harmony Gateway
Make your first RPC call on Harmony's Blockchain Gateway.
Ready for production?
Get 200 requests/second, priority support and advanced blockchain features.
Global Load Balancer
Route to nearest node
Batch RPC Calls
Multiple requests at once
Archive Nodes
Historical blockchain data
Debug & Trace
Advanced debugging
Advanced Analytics
Usage & performance
Bring Your Own RPC
Custom RPC gateways
Get Free API Key
Increase your limit and access all Harmony features in Tatum Development Platform.
Estimate Gas on Harmony
Calculate the optimal gas fee for any transaction on Harmony.
Smart Contract Tools on Harmony
Deploy, create, and interact with smart contracts on Harmony.
Accessible to Everyone
No signup. No paywalls. Just RPC that works. Great ideas come from everywhere.
Our Mission
With love by Tatum
Blockchain Data
Indexed Harmony Data Insights
Complete on-chain data access for Harmony. Query wallets, tokens, NFTs, and transaction history with lightning-fast APIs - no need to run your own nodes.
About Harmony
The Harmony RPC documentation provides developers with a detailed guide to interact with the Harmony blockchain programmatically. Harmony uses a unique sharding mechanism and an effective proof-of-stake (EPoS) consensus to offer scalable and fast transactions with low fees. The documentation includes key API endpoints for querying blockchain data, managing transactions, and interacting with smart contracts. Harmony’s architecture makes it ideal for scalable decentralized applications (dApps), particularly in decentralized finance (DeFi) and enterprise solutions.
FAQ
Frequently Asked Questions
Everything you need to know about Harmony RPC endpoints
What is Harmony RPC?
Harmony RPC (Remote Procedure Call) is an interface that allows developers to interact with the Harmony blockchain. It enables you to read data, send transactions, and deploy smart contracts programmatically using standard JSON-RPC methods.
How do I connect to Harmony using these RPC endpoints?
Simply copy the RPC endpoint URL from above and configure it in your Web3 library (ethers.js, web3.js), wallet (MetaMask, Trust Wallet), or development tool (Hardhat, Truffle). The endpoint works immediately with no registration required for the free tier.
What are the rate limits for free Harmony RPC?
Free tier RPC endpoints are limited to 5 requests per minute. This is perfect for testing and development. For production applications, we recommend upgrading to Tatum Premium which offers 200 requests per second with no daily limits.
Is Harmony RPC free forever?
Yes! Our free tier Harmony RPC endpoints are free forever with 5 requests per minute. This tier is perfect for learning, testing, and small projects. There are no hidden fees or time limits on the free tier.
What's the difference between mainnet and testnet?
Mainnet is the live Harmony blockchain where real transactions occur with real assets. Testnet is a separate network used for testing and development with free test tokens. Always test your dApp on testnet before deploying to mainnet.
Can I use these endpoints in production?
Free tier endpoints can be used in production for low-traffic applications (under 5 req/min). For production apps with higher traffic, we strongly recommend Tatum Premium for guaranteed uptime, faster rate limits, and enterprise SLA.