chain.openverbs.com
https://chain.openverbs.com/v1/gasPaid verification
How it worksNo sponsored paid call yet.
Pay this endpoint once from your own wallet (Base USDC, up to $1.00) and we call it and record what came back. Your wallet pays the listed recipient directly; Agent Tools never holds funds. Sponsored checks prove delivery; they do not count as demand.
Quality grade
How grading works- ✓ Answers a real HTTP 402 challenge
- ✓ Publishes a /.well-known/x402 descriptor
- ✓ Payment address on record
- ✓ Settlement network declared
- ✓ Price declared
x402 readiness
Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here A, 90.4/100), which weighs availability, payability and on-chain demand. How the two differ
| Valid payment requirements | 10/10 | Payment requirements carry a payee, a mainnet network and a price. |
| Live 402 challenge | 25/25 | Paid endpoint answers with an HTTP 402 challenge (189 ms). |
| x402 version | n/a | x402 version not observed yet. |
| Signed descriptor | n/a | No x402 standard defines a signed descriptor. |
| Uptime (30 days) | 15/15 | 32/32 probes succeeded over 30 days (100%). |
| Resource declaration | 10/10 | Declares 27 paid resource(s). |
| Verified identity | 5/10 | Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control. |
| Freshness + modern flags | 1/5 | not seen in a source for over 30 days; declares x402. |
| Security declaration | n/a | Payment is the access control for an x402 resource. |
Compared with peers
Against 10,060 reachable x402 APIs in our daily snapshot (2026-11-12 01:39 UTC). Display only; it does not change search order.
- Readiness
- Higher than 80% of peers
- This listing 88 · peer median 78
- Latency
- Faster than 54% of peers
- This listing 189 ms · peer median 205 ms
Where it loses the most points, and how to win them back
- Verified identity −5
— Claim the listing and prove control of its domain.
Now: Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control.
- Freshness + modern flags −4
— Keep the listing current in the registry or source it comes from.
Now: not seen in a source for over 30 days; declares x402.
Paid endpoints
27 resource(s) advertised by this origin. Each price below is that resource's own x402 price; the headline price is the range across them.
https://chain.openverbs.com/v1/gas
Live gas conditions for an EVM chain: current gas price, the latest block's base fee (EIP-1559) and the suggested max priority fee — all in both wei and gwei. Ground truth an agent can't compute. Reads live on-chain data with automatic endpoint fallback.
https://chain.openverbs.com/v1/address
Native ETH / wallet balance for an address on any EVM chain: native balance (wei + ether), transaction count (nonce), and whether it's a contract or an externally-owned account (with deployed code size). Reads live on-chain data with automatic endpoint fallback.
https://chain.openverbs.com/v1/token
Live ERC-20 metadata read directly from the contract: name, symbol, decimals and total supply (raw + decimal-formatted). Handles both string and legacy bytes32 name/symbol encodings. Returns `isToken:false` for EOAs or non-token contracts. Reads live on-chain data with automatic endpoint fallback.
https://chain.openverbs.com/v1/token-balance
Live ERC-20 token balance held by a wallet: calls `balanceOf(address)` on the token contract and returns the raw balance plus a decimal-formatted amount (using the token's own decimals) with its symbol. Distinct from `address` (native ETH balance) and `token` (contract metadata). Reads live on-chain
https://chain.openverbs.com/v1/token-allowance
Live ERC-20 spending allowance an owner has granted a spender: calls `allowance(owner, spender)` on the token and returns the raw amount, a decimal-formatted amount (using the token's decimals) with its symbol, and an `isUnlimited` flag for effectively-infinite approvals. Use it to audit token appro
https://chain.openverbs.com/v1/gas-estimate
Simulate a transaction before signing: runs `eth_estimateGas` for `{ to, from?, data?, value? }` and returns the estimated gas units and estimated fee (current gas price x gas, in wei + ETH). If the node rejects the call it returns `ok:false` with the decoded `revertReason` (why it would fail) inste
https://chain.openverbs.com/v1/tx
Live status and details of a transaction by hash: success/failed/pending, from/to, value (wei + ether), nonce, block number, gas used, effective gas price and any created contract address. Returns `found:false` for unknown hashes. Reads live on-chain data with automatic endpoint fallback.
https://chain.openverbs.com/v1/block
Live block summary by number, hex, or tag (latest/earliest/pending/safe/finalized; default latest): number, hash, parent, timestamp (unix + ISO), transaction count, gas used/limit, base fee and miner. Reads live on-chain data with automatic endpoint fallback.
https://chain.openverbs.com/v1/logs
Query a contract's event logs over a bounded block range via `eth_getLogs`: filter by `address` (required) and optional `topics`, get back raw logs (topics, data, block, tx hash, log index) with ERC-20/721 Transfer logs auto-decoded to `{from, to, value}`. Block span is capped (large windows are cla
https://chain.openverbs.com/v1/receipt
Live transaction receipt by hash via `eth_getTransactionReceipt`: success/failed status, block number, from/to, created contract address, gas used, cumulative gas, effective gas price (wei + gwei), tx type and the emitted event logs (capped). Complements `tx` (which reads the transaction itself). Re
https://chain.openverbs.com/v1/proxy
Detect whether a contract is an upgradeable proxy and resolve its implementation: reads the standard EIP-1967 implementation/admin/beacon slots, EIP-1822 (UUPS), the OpenZeppelin legacy slot, and EIP-1167 minimal-proxy bytecode. Returns the proxy type, implementation, admin and beacon addresses when
https://chain.openverbs.com/v1/explain
Decode a transaction into plain language: native ETH transfer, contract call (with decoded method name for common ERC-20/DEX functions like transfer, approve, swap, mint, multicall) or contract creation; ERC-20 and NFT (ERC-721) transfers it triggered (token, from, to, amount/tokenId from logs); gas
https://chain.openverbs.com/v1/token-risk
Deterministic risk screen of an ERC-20 token from on-chain bytecode and metadata, no third-party risk API. Flags privileged or abuse capabilities: blacklist/freeze, owner mint, pausable transfers, upgradeable proxy and a privileged owner, plus tokens missing symbol/decimals or code. Returns each fla
https://chain.openverbs.com/v1/ens-resolve
Resolve an ENS name (like alice.eth) to its Ethereum address, read live from the ENS resolver on Ethereum mainnet. Offchain names such as *.base.eth resolve too. Returns `found:false` (a real answer, not an error) when the name has no address record. Live reads with automatic endpoint fallback.
https://chain.openverbs.com/v1/ens-reverse
Reverse-resolve an Ethereum address to its primary ENS name (the reverse record set by the owner), read live on Ethereum mainnet. Returns `found:false` when the address has no primary name set. Live reads with automatic endpoint fallback.
https://chain.openverbs.com/v1/ens-records
Read an ENS name's address plus its text records (avatar, url, email, description, com.twitter, com.github and more) in one call, live from the resolver on Ethereum mainnet. Pass `keys` to fetch specific records, or omit it for a sensible default set. Only records that are set are returned. Live rea
https://chain.openverbs.com/v1/nft-metadata
Resolve one NFT (contract + tokenId) into normalized metadata: name, description, image, attributes and token standard (ERC-721 or ERC-1155). Reads the on-chain tokenURI/uri, then fetches and normalizes the metadata document (ipfs/ar/http/data), rewriting ipfs image links to a gateway URL. Returns `
https://chain.openverbs.com/v1/decode
Turn a 4-byte function selector or full calldata into its human-readable function signature, and (when calldata is present) the decoded argument values. Supply an `abi` for a fully deterministic offline decode, or omit it to look the selector up in public signature registries. Reads with automatic f
https://chain.openverbs.com/v1/abi
Get the verified contract ABI and verification metadata for a deployed contract by address, sourced from Sourcify. Returns the contract ABI (to decode or call it), contract name, compiler/language, match type, and proxy resolution (is-proxy plus implementation addresses). Supports Ethereum, Base, Ar
https://chain.openverbs.com/v1/source
Get the verified Solidity/Vyper source code for a deployed contract by address, sourced from Sourcify. Returns every source file (path + content), the contract name, language, compiler version and compiler settings (optimizer, evmVersion) — the full human-readable source an agent needs to read, audi
https://chain.openverbs.com/v1/read-contract
Call a read-only (view/pure) function on any deployed contract via eth_call and get the decoded result. Give the contract address and a human-readable signature (e.g. 'balanceOf(address) view returns (uint256)') plus args; include return types to decode outputs, else raw hex is returned. Reads allow
https://chain.openverbs.com/v1/sanctions
Screen a crypto wallet address against the OFAC SDN sanctions list (US Treasury Specially Designated Nationals) before transacting. Multi-chain across ~20 assets (BTC, ETH, USDT, TRX, XMR and more); EVM 0x addresses match case-insensitively. Returns whether the address is sanctioned plus the listed
https://chain.openverbs.com/v1/bytecode
Fetch deployed EVM contract runtime bytecode and its Keccak-256 code hash to fingerprint or compare contracts, or feed a disassembler. Supports Ethereum, Base, Arbitrum, Optimism and Polygon, with optional historical block reads. Returns full hex code, byte size and isContract; an empty-code address
https://chain.openverbs.com/v1/btc-fees
Live recommended Bitcoin transaction fee rates (in sat/vB) for next-block, ~30-minute, ~1-hour, economy and minimum confirmation targets, straight from the mempool. Also estimates the total fee (in sats and BTC) for a transaction of the given virtual size, so an agent can pick a fee tier and know th
https://chain.openverbs.com/v1/btc-mempool
Live snapshot of the Bitcoin mempool: number of unconfirmed transactions, total pending virtual size (bytes and MB), the current backlog in blocks, total fees pending (sats and BTC), the fee-rate histogram, and the current chain tip height. Lets an agent gauge network congestion and time a transacti
https://chain.openverbs.com/v1/btc-address
Balance and activity for a Bitcoin address (base58 1…/3… or bech32 bc1…): confirmed balance (sats and BTC), total received and sent, confirmed transaction count, and unconfirmed/pending value and tx count from the mempool. On-chain ground truth an agent cannot compute locally.
https://chain.openverbs.com/v1/btc-tx
Look up a Bitcoin transaction by txid: confirmation status, block height and time, fee (sats), effective fee rate (sat/vB), size, weight and virtual size, input and output counts, and total output value (sats and BTC). On-chain ground truth for verifying a payment.
How to call
curl -sS -i -X POST https://chain.openverbs.com/v1/gas # expect HTTP 402 Payment Required (about 0.001 USDC/call)
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