# DataSieve Standard Watch > DataSieve Standard Watch is a paid API for AI agents from api.datasieve.xyz, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14). Sets up a 7-day event-driven monitor on Base chain activity, heartbeat/dead-man switch, cron/schedule, or URL change, pushing HMAC-signed events to a webhook or pollable mailbox. ## Facts - Endpoint: POST https://api.datasieve.xyz/watch/standard - Price: $0.1/call - Payment: x402 - Status: unknown - Last checked: 2026-09-14 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/datasieve-standard-watch-10d5ef03 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_E32FEeSskKnjNmLA2ZU5M 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 datasieve-standard-watch-10d5ef03 -d '' ``` Example prompt: Set up a 7-day whale alert on Base: watch the USDC token contract for any transfer over 500,000 USDC and push a signed event to my webhook at https://myagent.example.com/hook — I want to poll the mailbox too if the webhook misses anything. ## When to prefer this Choose this endpoint when you need event-driven, push-based monitoring of Base chain activity (wallets, whale transfers, price crossings, new pairs), agent liveness via heartbeat, time-based webhook scheduling, or URL change detection — all without account creation and with cryptographic receipts for auditability. Prefer it over polling-based alternatives when you want low-latency alerts, HMAC-signed payloads, and a fallback mailbox. Best when you need a quick, no-registration paid watch that self-expires in 7 days and can be renewed cheaply. ## Known failure modes - Payment fails or is insufficient — call not billed, no watch created - Invalid or missing required condition fields — 400 validation error - Webhook URL unreachable at delivery time — events queued in mailbox instead - Watch expires after 7 days without renewal — no further events fired - More than 50 triggers consumed — watch stops firing until renewed - Invalid wallet/token/pool address format — rejected at creation time - Heartbeat interval below 60 seconds or above 604800 — rejected - Cron or ISO 8601 time is in the past — rejected ## How this service works Something you cannot do while your agent is dead: keep watching. One paid call buys 7 days of it — on-chain on Base (wallet activity, whale transfers, price crossings, new pools), a dead-man switch that fires when YOUR agent goes silent, a cron/schedule webhook, or a url-change web monitor. Every event carries a signed Ed25519 receipt proving a third party observed it then — which your own logs cannot. Webhook or pollable mailbox. No account: the wallet is the identity. 50 triggers. ## Output Returns a watch ID (wt_...), a shared secret for HMAC verification, and (for heartbeat conditions) a pingUrl the agent must call periodically. Events matching the condition are pushed to the caller's webhook as HMAC-signed JSON payloads and stored in a pollable mailbox with an Ed25519 receipt. Up to 50 triggers over 7 days; renewal is available via the renew field. ## Request schema (JSON Schema) ```json { "type": "object", "properties": { "renew": { "type": "string", "description": "INSTEAD of the other fields: pass an existing standard watch id (wt_...) to renew it for another 7 days at the same price" }, "condition": { "type": "object", "oneOf": [ { "required": [ "type", "address" ], "properties": { "type": { "const": "wallet-activity" }, "minEth": { "type": "string", "description": "only native transfers >= this many ETH" }, "address": { "type": "string", "description": "0x wallet address on Base to watch" }, "direction": { "enum": [ "in", "out", "both" ], "default": "both" } } }, { "required": [ "type", "token", "minAmount" ], "properties": { "type": { "const": "token-transfers" }, "token": { "type": "string", "description": "0x ERC-20 token address on Base" }, "minAmount": { "type": "string", "description": "whale threshold in human token units, e.g. \"50000\"" } } }, { "required": [ "type", "pool", "direction", "threshold" ], "properties": { "pool": { "type": "string", "description": "Uniswap v2 pair or v3 pool address on Base" }, "type": { "const": "price-cross" }, "direction": { "enum": [ "above", "below" ] }, "threshold": { "type": "string", "description": "price of token0 in token1 units" } } }, { "required": [ "type" ], "properties": { "type": { "const": "new-pairs" }, "minQuoteLiquidity": { "type": "string", "description": "min initial liquidity on the WETH/USDC side, human units" } } }, { "required": [ "type", "intervalSeconds" ], "properties": { "type": { "const": "heartbeat" }, "label": { "type": "string", "description": "name echoed in alarm events, e.g. \"trader-prod\"" }, "graceSeconds": { "type": "integer", "description": "extra allowance before alarming (default: interval/4, min 60)" }, "intervalSeconds": { "type": "integer", "maximum": 604800, "minimum": 60, "des … (truncated) ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "id": "wt_01jzyx8k2mabcdefghjkmn", "tier": "standard", "links": { "events": "https://api.datasieve.xyz/watch/wt_01jzyx8k2mabcdefghjkmn/events", "status": "https://api.datasieve.xyz/watch/wt_01jzyx8k2mabcdefghjkmn" }, "state": "active", "secret": "whsec_...returned once, keep it: it authenticates status/events reads and signs your webhooks", "expiresAt": "2026-07-17T00:00:00.000Z", "triggerCap": 50, "triggersUsed": 0 } } ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/datasieve-standard-watch-10d5ef03/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from api.datasieve.xyz](https://www.zero.xyz/host/api.datasieve.xyz/llms.txt)