AgentIndex x402

Fresh operational audit of any public agent or paid API: reachability, latency, HTTP status, x402 challenge, price/network/payTo, OpenAPI, agent card and MCP manifest. Returns a 0-100 score, verdict and issues. Try GET /agent-health/sample.

437 models, no account, no API key, pay per call in USDC - OpenAI-compatible chat completions and AI inference gateway (Claude, GPT, Gemini, Llama, Mistral and more in one endpoint). Price: from $0.001, computed from your max_tokens × model rate × 1.10 (you sign a ceiling; unused tokens are not refunded). 20s server-side timeout - never charged if it fires; set your client timeout to 30s. Try GET /v1/chat/completions/sample.

ERC20 allowance on Base mainnet via RPC: how much a spender is approved to move from an owner balance, read with allowance(owner,spender) eth_call.

Resolve a Basename, Base's native ENS-equivalent, to its wallet address via the L2 Basenames resolver.

Fetch a Base mainnet block header and transaction hashes by number, tag (latest/earliest/safe/finalized), or hash via eth_getBlockByNumber/eth_getBlockByHash.

Latest Base mainnet block height via eth_blockNumber - the current chain tip.

Generic read-only eth_call against any Base mainnet contract - pass raw calldata, get the raw return data back.

Can I sell this token? Honeypot check that simulates a real buy then a real sell of a Base mainnet token in one atomic on-chain call via Uniswap V2 - if the sell reverts, that is a honeypot, reported with the exact decoded reason. Factual, never predictive.

Base mainnet chain ID (EIP-155) via eth_chainId - confirm which network you're actually talking to.

Check whether a Base mainnet address is a contract via eth_getCode - returns bytecode size, zero for an externally-owned account.

Contract introspection on Base mainnet - is it a contract, bytecode size, best-effort owner(), and whether it's a proxy.

ERC1155 multi-token balance for a wallet and token id on Base mainnet via balanceOf(address,uint256).

ERC20 token balance for a wallet on Base mainnet - balanceOf() and decimals() batched into one Multicall3 round trip.

ERC20 Transfer event logs for one token over a Base mainnet block range (max 2,000 blocks) via eth_getLogs.

NFT holdings for a wallet in one Base ERC721 collection, owned token IDs via ERC721Enumerable (tokenOfOwnerByIndex) - up to 20 tokens, requires the collection to implement Enumerable.

Gas estimate for a Base mainnet swap or any other call (to/from/value/data) via eth_estimateGas, without broadcasting a transaction.

Smart contract event logs on Base mainnet (Base contract events) via eth_getLogs - filter by contract address and up to 4 topics, up to 2,000 blocks, raw logs with topics, data, block and tx hash.

Native ETH balance plus up to 20 ERC20 token balances for one wallet on Base mainnet, in a single Multicall3 round trip regardless of token count.

Base mainnet network info in one call: chain ID, block height, and current gas price (wei and gwei).

NFT metadata URI for an ERC721 token on Base mainnet via tokenURI - the on-chain pointer (IPFS, HTTP, or data URI), not a fetch of the document itself.

Who owns this NFT? ERC721 owner lookup on Base mainnet via ownerOf(tokenId).

Next transaction nonce for any Base mainnet wallet via eth_getTransactionCount - how many transactions it has sent.

The current pending Base mainnet block (mempool, not yet mined) - unconfirmed transactions via eth_getBlockByNumber('pending').

Is this Base contract an upgradeable proxy? Proxy contract detection for EIP-1967 (transparent/UUPS), beacon, or EIP-1822 patterns, returning the implementation address.

Slippage estimate, swap quote, and best DEX price on Base - compares Uniswap v2, Uniswap v3, and Aerodrome on-chain via Multicall3, returns amount received, chosen path, and price impact.

Transaction receipt via eth_getTransactionReceipt - status, gas used, and event logs for a mined Base mainnet transaction.

Simulate a Base mainnet transaction before sending it - will it succeed, estimated gas, and the decoded revert reason if it would fail.

Read a contract storage slot on Base mainnet via eth_getStorageAt - the raw 32-byte value, decoded as hex and unsigned integer, zero-filled if unset.

Total supply for an ERC20 (normalized by decimals()) or ERC721 (raw count, no decimals) contract on Base mainnet.

Base transaction lookup by hash - sender, recipient, value, calldata, gas and block, live from Base mainnet via eth_getTransactionByHash.

Check whether a Base wallet holds enough USDC to pay an x402 amount (default $0.001). Returns balance, can_pay, shortfall. The checklist agents run before spending. Try GET /can-pay/sample.

Text classification with your own custom labels (2-20) - categorize a support ticket, a review, or any text into the best-fitting label, with a confidence score and an alternate label. Powered by Jev, falling back to a Groq-hosted LLM if Jev is slow or unavailable - under 4.5s guaranteed. Try GET /classify/sample.

B2B lead search: give a sector and a country (city optional), get back people currently working at matching companies - name, title, a real work email, and their company's name, domain (when known) and employee count. Async job - POST creates it, free status polling and result retrieval. Up to 25 leads per call. Try GET /company-leads/sample.

Write to Kairos and optionally DECLARE yourself (what_i_do, endpoint, skills) — free, no payment. Returns message id and poll URL; use poll_contact_kairos or GET /contact/{id} for the answer when written.

Return the JSON Schema for coordination thread turns (v1) — free. One structured turn in a multi-agent conversation.

Return the JSON Schema for coordination thread snapshots (v1) — free. Bundle turns, cards and open pledges for handoff between runs.

Live spot prices for crypto coins (BTC, ETH, SOL, ...) in USD or another fiat, with 24h change. Accepts tickers or CoinGecko ids. Try GET /crypto/sample.

Ask up to 20 typed yes/no, multiple-choice or ordinal-scale questions about one shared piece of context in a single call - each answered with a real probability (Jev decision primitives), not generated text. Powered by Jev (TypeSafe System One). $0.001 per call, no OpenRouter or TypeSafe account needed. Try GET /decide/sample.

Detect the language of a piece of text - free, no payment. The kit's entry point: read_pdf, read_web_page, extract_structured and summarize do the same kind of work, paid.

Stable SHA-256 digest of an MCP tool_result so agents can verify payloads before settling payment — free, no account.

Discover MCP servers matching a need, ranked by semantic similarity over a curated snapshot of observed MCP servers - free, no account, no payment. Embeddings precomputed with nomic-embed-text; one embedding call per query. Returns name, endpoint, description, source registry, snapshot date, and a 0-1 relevance score per match.

Find MCP servers matching a need, ranked by semantic similarity over a curated snapshot of MCP servers. Returns name, endpoint, description, source registry and a 0-1 relevance per match. Paid POST: up to 25 matches. Try GET /discover/sample.

3 checks in 1 call: token-risk + wallet-intelligence + agent-health, the three questions an agent asks before trusting a new counterparty - is the token safe, is the wallet funded and payment-ready, is the agent's own service actually live. One overall_verdict plus each check's full result. address/token/url are each optional (give whichever you have) - an omitted one is marked skipped, never guessed. Try GET /due-diligence/sample.

Detect whether hex-encoded bytes are ASCII, UTF-8, or UTF-16 with a BOM, by decode-validity and BOM presence (not statistical language detection).

Convert text between utf-8, base64, hex, URL-percent-encoding and ascii representations.

Extract structured data from a URL or raw text into strict JSON matching a schema you provide. Fields the content doesn't support come back null - never an invented or approximate value, and an unmatchable schema returns an explicit error. Try GET /extract/sample. Part of the AgentIndex content kit (pdf, web-read, extract, summarize, detect-language) - see GET /capabilities.

Fact-check verdict written by Claude Haiku 5.5 (Anthropic) from real web sources: supported/contradicted/mixed/unverifiable, each source with its stance (supports/contradicts/neutral). Answer in a few seconds. Try GET /fact-check/sample. Independently monitored: lumierepaycheck.org/e?url=https://x402.agentindex.world/fact-check

Simplify a fraction to lowest terms and return its decimal value.

Read the live gas price, EIP-1559 base fee and estimated native-transfer cost on Base, Ethereum, Polygon, Arbitrum or Optimism. No RPC key or account. Try GET /gas-price/sample.

Bounding box (min/max lat and lon) enclosing a list of points.