TraceFast API
Open an entity page in TraceFast →
The TraceFast API gives programs the same Ethereum data the app is built on: blocks and transactions, tokens and contracts, what an address holds and does, and what the TraceFast knowledge graph states about it. Every method is read-only, answers JSON and serves Ethereum mainnet.
Ways to call
| REST with an API key | MCP for AI agents | Pay per call with x402 | |
|---|---|---|---|
| For | applications and services | AI agents — Claude Code, Cursor, your own | AI agents without an account |
| Methods | every method | every method, as a tool | every method |
| Address | https://tracefast.xyz/api/v1 | https://tracefast.xyz/mcp | https://mpp.tracefast.xyz/api/v1 |
| Credential | an x-api-key header | the same key, or sign-in with your TraceFast account | none — each call is paid in USDC on Base |
| Account | a subscription plan | the same plan and limits | none |
| Start here | API keys | Connect an AI agent over MCP | Paying with x402 |
The REST paths are the same with a key and over x402, and a tool takes its method's parameters under the same names. The data and the refusals are the same on all three — see Conventions.
curl -s https://tracefast.xyz/api/v1/chains/1/blocks/latest \
-H "x-api-key: $TRACEFAST_API_KEY"Methods
All methods lists every method on one page — its path, parameters, what it returns and the plan it needs. By family:
- Addresses — resolving a name, ENS name or token symbol to an address, an address at a glance, when it was active, its native balance history, portfolio, token balances and counterparties, and three feeds: its transactions, token transfers and internal transfers.
- Attributes & relations — what the TraceFast knowledge graph has proven about an address and how it points at other addresses: now, at a past block, over time, and the evidence behind each fact.
- Tokens — a token contract, its holders, its transfers, and network-wide token statistics.
- Blocks — the latest block, one block, its transactions, withdrawals and EIP-7702 authorizations, and the accounts it touched.
- Transactions — one transaction, its events, why it reverted, its execution trace — whole or frame by frame — and the storage it wrote.
- Contracts — a deployed contract, its bytecode, function selectors, proxy implementations and events.
- Consensus — the validator activation and exit queues, now and over time, the block-proposal leaderboard, and one validator's withdrawals.
- Risk — which issuer contracts have placed an address on their on-chain blacklist, and every listing, unlisting and enforcement event about it.
Every response carries meta.docs: the page of the method that answered.
Stability
Every method is stable: its shape is frozen, an incompatible change comes as a new method, and a method is retired only with 90 days' notice — see Stability.
Discovery
No key and no payment is needed to read what the API offers:
| URL | What it is |
|---|---|
https://tracefast.xyz/api/v1/openapi.json | the OpenAPI document for every method |
https://mpp.tracefast.xyz/api/v1/openapi.json | the same methods as sold over x402 |
https://mpp.tracefast.xyz/llms.txt | the methods and their x402 prices in plain text, for agents |
TraceFast is also listed on Agentic Market, the x402 Bazaar catalog operated by Coinbase, where the price and the route template are shown before you pay.
Related pages
- All methods — every method on one page
- API keys — sending the key, plans and limits
- Connect an AI agent over MCP — the methods as tools for AI agents
- Paying with x402 — the key-less way, for AI agents
- Conventions — requests, responses, errors and pagination
- Addresses & Labels — the same knowledge in the app
Last updated 22 Oct 2026, 08:06 UTC · verified against TraceFast v1.0.261 · Markdown