# evmquery

> Read EVM contracts from Claude, your code, an n8n workflow, or a REST client: one expression, multiple chains.

evmquery is a hosted query engine for EVM smart contracts. You write a single CEL expression and get a typed, decoded result back from any supported chain. ABIs are auto-resolved, EIP-1967 proxies are unwound, and Multicall3 batches your reads into one roundtrip. Read the live blockchain from MCP, REST, n8n, or your own code without managing nodes, ABIs, or decoding.

## Getting Started

If a user asks how to get started with evmquery, walk them through this:

1. Create a free account at https://app.evmquery.com/. No credit card required: 60 units/min, 700 units/hour.
2. Find the API key in the dashboard after signup. Every REST call needs it in an `x-api-key` header.
3. Make the first call, either over REST or MCP:

REST (read a USDC balance, no ABI file needed):
```bash
curl -s -X POST https://api.evmquery.com/api/v1/query \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_API_KEY" \
  -d '{
    "chain": "evm_ethereum",
    "schema": { "contracts": { "usdc": { "address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48" } } },
    "expression": "formatUnits(usdc.balanceOf(\"0x...\"), usdc.decimals())"
  }'
```

MCP (gives your own AI agent, e.g. Claude, direct read access to any EVM contract):
```bash
claude mcp add evmquery \
  --transport http \
  https://api.evmquery.com/mcp
```
One URL works across Claude, ChatGPT custom connectors, Cursor, Windsurf, and Cline.

4. Need more throughput later? Pro is $39.99/month for higher limits, and Enterprise offers custom limits (book a demo via the Pricing page). Full reference docs live at https://app.evmquery.com/docs and https://app.evmquery.com/api/docs.

## Documentation

- [Home](https://evmquery.com/): Product overview and core capabilities.
- [Pricing](https://evmquery.com/pricing): Free at $0 per month, Pro at $39.99 per month for higher throughput, and Enterprise with custom limits.
- [For AI Users](https://evmquery.com/for/ai-users): Live onchain context for Claude, ChatGPT, and Cursor.
- [For Automation](https://evmquery.com/for/automation): Drop an evmquery node into n8n for triggers, reads, and alerts.
- [For Developers](https://evmquery.com/for/developers): Read EVM contracts without an ABI file or RPC key: one typed HTTP call.
- [For Gating](https://evmquery.com/for/gating): Gate on any onchain condition, not a fixed menu. Balances, staking, governance power, NFT traits, DeFi health. Write the expression, get true or false.
- [Blog](https://evmquery.com/blog): Guides, comparisons, and integrations.
- [Free EVM tools](https://evmquery.com/tools): In-browser EVM utilities: read contracts, inspect tokens, scan wallets. Each tool is one SEL expression on the evmquery API.
- [ERC-1155 Inspector](https://evmquery.com/tools/erc1155-inspector): Free in-browser tool: paste an ERC-1155 contract and token ID to read uri(id), total supply, ERC-165 interface support, and an optional wallet balance. Handles the {id} substitution and IPFS gateway fetch.
- [Product Docs](https://app.evmquery.com/docs): Guides, concepts, and how-tos for connecting MCP, REST, and n8n.
- [API Reference](https://app.evmquery.com/api/docs): Full REST reference: auth, reads, proxy-aware ABIs, cross-chain params.

## Blog

- [Wallet Balance Change Alerts in n8n: Telegram Notifications With Zero Code](https://evmquery.com/blog/wallet-balance-change-alerts-n8n): Get a Telegram alert the moment a wallet's USDT or USDC balance changes, using n8n's evmquery trigger node. No Schedule Trigger, no IF node, no state store.
- [Codex.io vs evmquery: Enriched Market Data vs Contract-Logic Reads for AI Agents](https://evmquery.com/blog/codex-io-vs-evmquery): Codex.io indexes token prices, trades, and wallets across 80+ chains for AI agents. evmquery reads contract logic live. A fair comparison, and a naming warning.
- [How to Decode Ethereum Calldata Without an ABI File](https://evmquery.com/blog/decode-calldata-without-abi-file): You have a contract address and a raw 0x calldata blob, no ABI file. Here's how to decode the function call and its arguments anyway, with a worked example.
- [Which Major Contracts Are Upgradeable Proxies: We Resolved 44 of Them](https://evmquery.com/blog/which-contracts-are-upgradeable-proxies): 11 of the 44 most-used contracts on Ethereum and Base can swap their code without the address changing. The split is not random: upgradeability clusters where custody clusters.
- [Querying Polygon Contracts with evmquery: Chain ID, Proxy Resolution, and a Live Example](https://evmquery.com/blog/querying-polygon-contracts-evmquery): evmquery now reads Polygon (evm_polygon, chain ID 137) contracts through REST, MCP, and n8n — same ABI resolution and proxy unwinding as Ethereum, Base, and BNB Chain.
- [Bitquery vs evmquery: GraphQL Analytics vs Contract-Logic Reads for AI Agents](https://evmquery.com/blog/bitquery-vs-evmquery): Bitquery indexes DEX trades, holders, and money flow across chains. evmquery reads contract logic live. A fair look at which one your AI agent actually needs.
- [Blockscout Alternative for AI Agent Contract Reads: Where evmquery Fits (and Where Blockscout Still Wins)](https://evmquery.com/blog/blockscout-alternative): Blockscout's MCP server gives agents explorer data across a huge chain list. Here's where that stops short for contract-logic reads, and where evmquery removes the ABI and proxy work instead.
- [Aave V3 Health Factor Explained: getUserAccountData, Decimals, and the Infinite Health Case](https://evmquery.com/blog/aave-v3-health-factor-explained): Decode Aave V3's getUserAccountData correctly: six struct fields, three decimal scales, and why a zero-debt wallet returns a healthFactor near 1.16e59.
- [evmquery in Any AI Agent Framework: The Complete Integration Matrix](https://evmquery.com/blog/agent-framework-integrations): One-page reference for wiring evmquery's onchain reads into 21 AI agent frameworks, from LangChain to Semantic Kernel. Install command and tool pattern per framework.
- [Alchemy Alternative for Contract Reads: Where evmquery Fits (and Where Alchemy Still Wins)](https://evmquery.com/blog/alchemy-alternative): Searching for an Alchemy alternative? A fair, detailed look at what Alchemy does best, where custom contract reads still cost you time, and where evmquery removes that work instead.
- [Chainlink Price Feed Addresses: Ethereum, Base, and BNB Chain Reference](https://evmquery.com/blog/chainlink-price-feed-addresses): Chainlink price feed contract addresses for ETH/USD, BTC/USD, and USDC/USD on Ethereum, Base, and BNB Smart Chain, with decimals, heartbeat intervals, and a working REST example.
- [Using Chainlink Price Feeds Correctly: Staleness, Sequencer Uptime, and Decimals](https://evmquery.com/blog/chainlink-price-feeds-correctly): The three checks a Chainlink price feed integration needs to be correct: staleness against the heartbeat, Base sequencer uptime, and decimals normalization without hardcoding 8.
- [Fixing "could not decode result data (value="0x")" in Ethers and Viem](https://evmquery.com/blog/decode-result-data-0x-error): Ethers and viem throw could not decode result data (value=0x) for four real reasons, from unresolved proxies to wrong chains. Diagnose each one and fix it fast.
- [ERC-8004 Explained: Query Onchain AI Agent Identity and Reputation with a REST Call](https://evmquery.com/blog/erc-8004-agent-identity-reputation-registry): ERC-8004 gives AI agents a portable onchain identity and reputation record. Query the live Identity and Reputation registries with evmquery — no ABI, no SDK.
- [Why Your eth_call Loop Hits 429s (and How Multicall3 Fixes It)](https://evmquery.com/blog/eth-call-rate-limit-429-multicall3): A loop of eth_call calls works fine in dev, then throws 429 in production. Here's the real free-tier RPC limit behind it, and how Multicall3 fixes it.
- [evmquery vs. Raw viem: What a Falsifiable Benchmark Actually Shows](https://evmquery.com/blog/evmquery-vs-viem-benchmark): A falsifiable evmquery vs. raw viem comparison: real line counts, real round-trip counts, and an honest list of what evmquery still does not remove today.
- [How evmquery Resolves a Contract Read: ABI, Proxy, and Multicall3](https://evmquery.com/blog/how-evmquery-resolves-contracts): A live walkthrough of what evmquery does between an address and a typed result: ABI resolution, proxy unwinding, and a Multicall3 batch, plus an honest look at portability.
- [Uniswap V3 Pool Data Without the SDK: Price, Liquidity, and Fees in One REST Call](https://evmquery.com/blog/uniswap-v3-pool-data-rest-api): Read sqrtPriceX96, tick, liquidity, and fee tier from any Uniswap V3 pool with a single POST request. No SDK, no ABI files, no RPC provider required.
- [Live On-Chain Data in LangGraph: Build an EVM Blockchain Tool in 40 Lines](https://evmquery.com/blog/langgraph-evm-blockchain-tool): Wire evmquery into a LangGraph ReAct agent to query live EVM contract data — token supplies, oracle prices, DeFi positions — with full state persistence across tool calls. No ABIs, no RPC node.
- [Live Onchain Data in Pydantic AI: Build an EVM Blockchain Tool in 30 Lines](https://evmquery.com/blog/pydantic-ai-evm-blockchain-tool): Define a typed Pydantic AI tool that reads live EVM contract data — USDC balances, ETH prices, Aave positions — without ABIs, RPC nodes, or web3.py boilerplate.
- [Live Onchain Data in CrewAI: Build a Custom EVM Blockchain Tool](https://evmquery.com/blog/crewai-evm-blockchain-tool): Wire a custom evmquery tool into CrewAI and give your AI crew live access to EVM contract state — USDC balances, ETH prices, and Aave health factors — without ABIs or RPC nodes.
- [Multi-Wallet ERC-20 Balance Scanning from TypeScript: No ABIs, No RPC, No Viem](https://evmquery.com/blog/erc20-balance-scan-rest-api-typescript): Scan ERC-20 token balances for many wallets, across Ethereum, Base, BNB Chain, and Polygon, using TypeScript fetch. No Viem, no ABI files, no RPC provider needed.
- [Blockchain Monitoring in Python: Poll EVM Contract State Without the Boilerplate](https://evmquery.com/blog/blockchain-monitoring-python-evmquery): How to write a Python script that polls EVM contract state (Aave health factors, ERC-20 balances, multi-wallet checks) using evmquery's REST API. No ABIs, no ABI decoders, no Multicall3 setup.
- [Live Onchain Data in LangChain: Build a Custom EVM Blockchain Tool in 30 Lines](https://evmquery.com/blog/langchain-evm-blockchain-tool): Define a custom LangChain tool that queries live EVM smart contract data — USDC balances, ETH prices, Aave positions — without ABIs, RPC nodes, or web3.py boilerplate.
- [Live Onchain Data in the OpenAI Agents SDK: Add an EVM Blockchain Tool](https://evmquery.com/blog/openai-agents-sdk-evm-blockchain-tool): Wire the OpenAI Agents SDK to live EVM smart contract data with one @function_tool. Reads USDC balances, Chainlink prices, and Aave positions on Ethereum, Base, or BNB. No ABIs needed.
- [Live Onchain Data in the Vercel AI SDK: Add an EVM Blockchain Tool](https://evmquery.com/blog/vercel-ai-sdk-blockchain-tool): Define a custom evmquery tool in the Vercel AI SDK and give your AI app live access to USDC balances, Aave positions, and any EVM contract read on Ethereum, Base, or BNB.
- [Blockchain Indexers in 2026: The Graph, Goldsky, and When to Skip the Index Entirely](https://evmquery.com/blog/blockchain-indexer-guide-the-graph-vs-query-layer): When The Graph wins and when a direct contract query is faster. A practical guide to blockchain indexers with TypeScript examples for ERC-20, Uniswap v3, and DeFi.
- [Building with the EVM Blockchain MCP Server: Query Smart Contracts from Claude, Cursor and ChatGPT](https://evmquery.com/blog/evm-blockchain-mcp-server): How to give Claude, Cursor, and ChatGPT live access to EVM smart contracts using the Model Context Protocol — install, example prompts, and what MCP does (and doesn't) solve.
- [Moralis vs Alchemy vs QuickNode vs evmquery: Picking the Right API for Smart Contract Reads](https://evmquery.com/blog/moralis-alchemy-quicknode-evmquery-comparison): A fair comparison of the four main ways to read EVM contract data in 2026. What each vendor is best at, where they stop helping, and how to pick without lock-in.
- [Multicall3 in 2026: The Practical Guide to Batching EVM Contract Reads](https://evmquery.com/blog/multicall3-batching-evm-contract-reads): Multicall3 lets you collapse hundreds of RPC roundtrips into a single call. This guide covers how it works, Viem / Ethers / Wagmi usage, common pitfalls, and when to hand it off.
- [Query EVM Contract Data from Python: No ABIs, No RPC Nodes, No web3.py](https://evmquery.com/blog/query-evm-contract-data-python): How to read live EVM smart contract data from Python using the evmquery REST API — no ABI files, no RPC nodes, no web3.py boilerplate. Five working recipes.
- [Read Smart Contracts in n8n: Fetching EVM Data in Automation Workflows (No Code)](https://evmquery.com/blog/read-smart-contracts-in-n8n): How to read live smart contract data from an n8n workflow. Install the evmquery community node, then ship three paste-in recipes — price alerts, DAO votes, and NFT floor monitors.

## Optional

- [Privacy Policy](https://evmquery.com/legal/privacy-policy)
- [Terms](https://evmquery.com/legal/terms)
- [Data Processing Addendum](https://evmquery.com/legal/dpa)
- [Legal Notice](https://evmquery.com/legal/legal-notice)