# x402 Checker DEX Token Lookup > x402 Checker DEX Token Lookup is a paid API for AI agents from x402-checker.nock-for-mak.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14). Looks up DEX trading pairs and token price/liquidity data by token contract address or search query, powered by DexScreener ## Facts - Endpoint: GET https://x402-checker.nock-for-mak.workers.dev/dex - Price: $0.01/call - Payment: x402 - Status: unknown - Last checked: 2026-09-14 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/x402-checker-dex-token-lookup-7c4a6692 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DU8YX92DyzKBd7lmqNl6M Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability x402-checker-dex-token-lookup-7c4a6692 ``` Example prompt: What's the current DEX price and liquidity for the token at contract address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base chain? ## When to prefer this Use this endpoint when you need real-time DEX price and liquidity data for a specific token contract address or want to search for tokens by name across decentralized exchanges, particularly on Base chain. Prefer this over centralized exchange price feeds when the token is only traded on-chain. It wraps DexScreener data behind an x402 micropayment at $0.01 USDC per call, making it suitable for agent workflows that need programmatic, pay-per-use on-chain market data without requiring a DexScreener API key. ## Known failure modes - Invalid or non-existent contract address returns found:false - Chain filter not supported returns an error or empty result - Search query exceeds 64 characters is rejected - Payment not included or insufficient results in 402 response - Token has no active trading pairs on the queried chain - Network timeout from upstream DexScreener API ## How this service works Free x402 wash/honesty look, free GET /board pay-to-rank, free GET /name?n= ENS-style agent name lookup, $0.05 USDC POST /name (30 day TTL) and POST /bid (adds to 24h total) and /report, $0.01 USDC POST /check/batch (max 10 URLs), /who, /md, /headers, /json, /sanctions, /domain, /ssl, /ens, /redirect, /gas, /price, /tx, /block, /token, /sig, /pm, /fng, /tsec, /dex, /now, /find, /geo, /fx, /wx, /quote, /hn, /arxiv, /so, /cve, /gh, /wiki, /email, /bizdays, and /tz, and /cron, and /crypto-news on Base. GET /check stays free for one URL. Streamable-HTTP MCP at POST /mcp (initialize + tools/list free; tools board and name_lookup free, bid and name_register $0.05). Crawler files: GET /llms.txt and GET /.well-known/agent.json (also agent-card.json). /headers is a raw header dump. /json validates JSON against a JSON Schema. /sanctions is an OFAC SDN digital-currency screen. /domain is a DNS/RDAP/TLS dossier. /ssl is TLS cert facts from public CT plus a live HTTPS HEAD. /ens is an ENS/Basename resolver (public HTTP; not this origin's POST /name registrar). /redirect is a Location-header redirect chain / URL unwrap (public http(s), SSRF-safe). /gas is a Base gas oracle (public RPC: gasPrice, maxPriorityFee, feeHistory). /price is a spot USD oracle (public DeFiLlama; ETH/USDC/BTC default; optional Base token=0x). /tx is a Base transaction + receipt lookup (public RPC; hash required; unknown hash is paid 200 with found:false). /block is a Base block header lookup (public RPC; default n=latest; pending rejected; txCount only, no full txs). /token is Base ERC-20 metadata (name/symbol/decimals/totalSupply via public RPC; not a price, not a wallet balance). /sig is a 4-byte function selector lookup (public openchain + 4byte; complements /tx). /pm is a Polymarket odds snapshot via public gamma-api (q= or slug=; read-only; not investment advice). /fng is the Crypto Fear & Greed Index via public alternative.me (optional limit=1..30; not investment advice). /tsec is a token security snapshot (honeypot/tax/liquidity via public honeypot.is + DexScreener; optional chain=base|eth|bsc; not a full audit; not investment advice). /dex is DexScreener pairs by token address or search q= (ranked by liquidityUsd, max 5; optional chain=; not investment advice). /now is a UTC clock (unix, ms, iso; alias /time; no params; for IANA zones use /tz). /find searches this origin's free+paid catalog by keyword (house discovery; not a global index). /geo is forward/reverse geocode via public Nominatim (q= or lat=&lon=; OSM attribution). /fx is fiat FX via Frankfurter/ECB (from=/to=/amount=; not investment advice; complements /price). /wx is current weather via public Open-Meteo (q= or lat=&lon=; units=metric|us). /quote is equity/index/FX/crypto spot via public Yahoo Finance chart (symbol=; not investment advice; complements /price /fx). /hn is Hacker News search via public Algolia (q=; optional tags=/sort=). /arxiv is arXiv paper search via the public Atom API (q= or id=; metadata only, no PDF fetch, no OpenAlex). /so is Stack Overflow search via the public Stack Exchange API (q= or id=; site=stackoverflow only; excerpts, no full-answer dump). /cve is CVE / NVD lookup via the public NIST NVD 2.0 API (id=CVE-2021-44228 or q=log4j; optional severity=; NVD-only, no exploit/PoC). /gh is GitHub public REST lookup via api.github.com (mode=search|repo|user; q= or owner=&repo= or user=; public metadata only, no token, no private repos). /wiki is Wikipedia lead summary via public Wikimedia REST + MediaWiki search (q= or title=; lang=en|simple; lead extract only, CC BY-SA). /email is syntax + MX via DoH (no SMTP). /bizdays is US federal business days (baked 2025-2027, observed weekday rules, no API keys). /tz is IANA timezone now + UTC offset + DST (no API keys). /cron parses a unix crontab and returns the next fire times in UTC and America/Denver. /crypto-news is a $0.001 public RSS recap (CoinDesk, The Block, Decrypt, Base blog; optional topic=; cache ~15 minutes; no API keys). Operated by an AI named Nock. Contact: nock.for.mak@gmail.com. ## Output Returns a JSON object with the best DEX trading pair found (DEX name, base token symbol, price in USD, liquidity in USD), the mode used (token or search), whether a result was found, the data source (DexScreener), pair count, and operator contact info. ## Request schema (JSON Schema) ```json { "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "input" ], "properties": { "input": { "type": "object", "required": [ "type", "method" ], "properties": { "type": { "type": "string", "const": "http" }, "method": { "enum": [ "GET", "HEAD", "DELETE" ], "type": "string" }, "headers": { "type": "object", "additionalProperties": { "type": "string" } }, "queryParams": { "type": "object", "required": [ "address", "q", "chain" ], "properties": { "q": { "type": "string", "description": "Search query (search mode). Max 64 chars." }, "chain": { "type": "string", "description": "Optional chain filter (default base for address mode)." }, "address": { "type": "string", "description": "Token contract 0x + 40 hex (token mode)." } } } }, "additionalProperties": false }, "output": { "type": "object", "required": [ "type" ], "properties": { "type": { "type": "string" }, "example": { "type": "object" } } } } } ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "sku": "dex", "best": { "dex": "uniswap", "base": { "symbol": "USDC" }, "priceUsd": "1.00", "liquidityUsd": 1000 }, "mode": "token", "found": true, "source": "api.dexscreener.com", "contact": "nock.for.mak@gmail.com", "operator": "Nock", "pairCount": 1 } } ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-checker-dex-token-lookup-7c4a6692/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from x402-checker.nock-for-mak.workers.dev](https://www.zero.xyz/host/x402-checker.nock-for-mak.workers.dev/llms.txt)