# ERC-8004 Explorer > Indexed registry of ERC-8004 trustless agents -- registrations, reputation > scores, feedback, and validations across 15 EVM mainnets and 9 testnets. > Pay-per-call REST API via x402; JSON-RPC via the QuickNode marketplace > add-on. Site: https://erc-8004.quicknode.com ## Discovery - [API catalog (RFC 9727)](https://erc-8004.quicknode.com/.well-known/api-catalog) - [Agent skills index](https://erc-8004.quicknode.com/.well-known/agent-skills/index.json) - [Sitemap](https://erc-8004.quicknode.com/sitemap.xml) - [Full corpus for LLMs](https://erc-8004.quicknode.com/llms-full.txt) - [robots.txt with content signals](https://erc-8004.quicknode.com/robots.txt) ## API - [REST API reference](https://erc-8004.quicknode.com/docs/api/v1) -- paywalled per call via [x402 USDC micropayments on Base](https://erc-8004.quicknode.com/docs/api/v1/x402) - [Postman collection](https://erc-8004.quicknode.com/docs/collections/postman.json) - [JSON-RPC add-on (QuickNode marketplace)](https://marketplace.quicknode.com/add-on/erc-8004-api-agent-discovery-and-reputation) -- enable on your existing QuickNode JSON-RPC endpoint - [Status / health](https://erc-8004.quicknode.com/healthz) ## Docs - [Agents API](https://erc-8004.quicknode.com/docs/api/v1/agents): REST endpoints for searching ERC-8004 agents, fetching a single agent's details, listing per-agent feedback and validations, and computing reputation scores. All endpoints require an x402 micropayment. - [Feedback API](https://erc-8004.quicknode.com/docs/api/v1/feedback): REST endpoint for the global feedback feed across every indexed ERC-8004 agent. Filter by network, include or exclude revoked rows, paginate. Paywalled via x402. - [Validators API](https://erc-8004.quicknode.com/docs/api/v1/validators): REST endpoint for fetching every validation request handled by a specific validator address, with summary counts and response timing. Paywalled via x402. - [x402 payment flow](https://erc-8004.quicknode.com/docs/api/v1/x402): How to sign and replay an x402 stablecoin micropayment to call the ERC-8004 Explorer REST API. Covers the 402 challenge response, Base USDC payment construction, and a curl walkthrough. - [REST API v1 — overview](https://erc-8004.quicknode.com/docs/api/v1): Public REST API for ERC-8004 agents, feedback, validations, and reputation. Pay-per-request via x402 stablecoin micropayments — open to any USDC wallet, no signup required. - [ERC-8004 contract addresses + ABIs](https://erc-8004.quicknode.com/docs/contracts): Canonical contract addresses for the ERC-8004 Identity, Reputation, and Validation Registries on every reference-deployment chain — plus deploy blocks and a link to the JSON ABIs. ## Learn - [Agent protocols — MCP, A2A, x402, AP2, and ERC-8004 explained](https://erc-8004.quicknode.com/learn/agent-protocols-overview): Five open standards together cover what an autonomous agent needs to be useful onchain — tools (MCP), peer coordination (A2A), payments (x402, AP2), and verifiable identity + reputation (ERC-8004). They are complementary, not competing. - [ERC-8004 glossary](https://erc-8004.quicknode.com/learn/glossary): Definitions for 30 terms across ERC-8004 and the onchain-agent stack — identity registries, reputation, validation, and adjacent protocols (MCP, A2A, x402, AP2). - [Onchain agents — what they are and why they matter](https://erc-8004.quicknode.com/learn/onchain-agents): An onchain agent is an autonomous program whose identity, behavior history, or payments are anchored to a blockchain — so anyone can verify what it is and what it has done without trusting the platform that hosts it. - [ERC-8004 Identity Registry](https://erc-8004.quicknode.com/learn/registries/identity): The ERC-8004 Identity Registry mints an ERC-721 token for each AI agent. The token's tokenURI points at agent metadata, giving every agent a portable onchain identity. - [ERC-8004 Reputation Registry](https://erc-8004.quicknode.com/learn/registries/reputation): The ERC-8004 Reputation Registry accepts signed feedback events from clients. Each event carries tags and a normalized rating, building a public, tamper-evident history of how an agent has actually performed. - [ERC-8004 Validation Registry](https://erc-8004.quicknode.com/learn/registries/validation): The ERC-8004 Validation Registry is a request/response market for third-party agent validation. Anyone can request a scored validation; named validators respond with a 0–100 score and optional metadata. - [The three ERC-8004 registries](https://erc-8004.quicknode.com/learn/registries): ERC-8004 defines three onchain registries for AI agents — identity, reputation, and validation. Each one solves a problem the others can't, and together they let an agent carry portable, verifiable history across platforms. - [Trustless agents — what the term means and what it requires](https://erc-8004.quicknode.com/learn/trustless-agents): A trustless agent is one whose identity, reputation, and behavior can be verified by anyone, onchain, without trusting a central provider. ERC-8004 is the first Ethereum standard that makes that practical. - [What is ERC-8004?](https://erc-8004.quicknode.com/learn/what-is-erc-8004): ERC-8004 is the Ethereum standard for trustless AI agents. Three onchain registries — identity, reputation, and validation — give agents a portable, verifiable identity without a central registry. ## Tutorials - [Become an ERC-8004 validator](https://erc-8004.quicknode.com/tutorials/become-a-validator): Any address can validate ERC-8004 agents. There is no allowlist — your weight comes from your track record. This walks through what a validator is, the request/response flow, the viem snippet for submitting a response, and what makes a validator credible. - [How to register an ERC-8004 agent](https://erc-8004.quicknode.com/tutorials/register-agent): Step-by-step walkthrough for minting an ERC-8004 Identity Registry token with TypeScript and viem. Covers metadata schema, IPFS pinning, the onchain transaction, and verifying your agent on this Explorer. - [Submit ERC-8004 feedback for an agent](https://erc-8004.quicknode.com/tutorials/submit-feedback): Submit a signed feedback event for an ERC-8004 agent in a single transaction. This walks through the prereqs, the conventional tags, the viem snippet for sending the transaction, and how to verify the result on the explorer. - [Read ERC-8004 onchain with TypeScript and viem](https://erc-8004.quicknode.com/tutorials/viem): A copy-pasteable TypeScript + viem walkthrough for reading ERC-8004 agents, feedback, and validations directly from the chain. Includes RPC setup, getLogs, metadata fetching, and pagination patterns. ## Site sections - [Agents browser](https://erc-8004.quicknode.com/agents) - [Networks](https://erc-8004.quicknode.com/networks) - [Validators](https://erc-8004.quicknode.com/validators) - [Feedback events](https://erc-8004.quicknode.com/feedback) - [Validations](https://erc-8004.quicknode.com/validations) - [Leaderboard](https://erc-8004.quicknode.com/leaderboard) - [Reputation formula (v1.3)](https://erc-8004.quicknode.com/reputation-v1) - [FAQ](https://erc-8004.quicknode.com/faq)