SubQuery Learn
Practical guides for on-chain builders.
Work through real RPC, indexing, and debugging tasks with runnable examples and checks you can bring into your own stack.
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6 guidesExplore the guides
- Indexing4 min read
Replay EVM events without duplicate side effects
Build an idempotent EVM event consumer with a block-hash cursor, transactional outbox, and a replay drill for retries and chain reorganizations.
Read guide - RPC Operations3 min read
Verify an EVM contract deployment with RPC
Catch wrong-chain deployments in CI by checking the RPC chain ID, transaction receipt, canonical block hash, and runtime bytecode before publishing an address.
Read guide - Solana3 min read
Read Solana wallet token balances without stale snapshots
Sum token accounts by mint using exact integers, keep a slot watermark, and prevent a slower Solana RPC response from replacing a newer wallet balance.
Read guide - RPC Operations6 min read
Smart Contract Security Best Practices: Verify On-Chain State Before You Trust It
A practical guide to one smart contract security habit every dApp developer should build: reading contract state through an RPC endpoint and handling failures explicitly, instead of trusting a single unverified response.
Read guide - RPC Operations5 min read
How to Check Optimism RPC Reliability Before You Ship
A practical guide to measuring Optimism RPC reliability yourself with a small Node.js health-check script, plus how to separate RPC access from indexing and querying.
Read guide - RPC Operations5 min read
How to Compare Dedicated vs Shared Node Access for Solana RPC
A practical method for measuring whether dedicated or shared Solana RPC access fits your workload, using a runnable Node.js health-check script and honest measurement instead of vendor claims.
Read guide
