{"uid":"cap_zTUiQKX1-cFxp9MOrnPvZ","slug":"order-book-depth-notional-dee35e84","name":"Order Book Depth Notional","description":"Sum price*size depth notional for a side ladder. Call when risk needs notional available within N levels. Returns depth_notional and levels_used as deterministic JSON for $0.001 USDC via x402 on Base. First-party local math only—no RPC, live market feed, API keys, storage, or mediagen. Advisory only; the caller owns capital, risk, and production controls.","url":"https://api.delx.ai/api/v1/x402/ob-depth-notional","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"levels":{"type":"array","description":"Array of {price,size} ladder levels"}}},"responseSchema":{"type":"json","example":{"schema":"delx/util-ob-depth-notional/v1","levels_used":2,"depth_notional":498.5}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_D7ux5wVpbVbF_riFg6ZYs","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes the total notional value (price × size sum) available within N levels of an order book side ladder","exampleAgentPrompt":"Calculate the total notional depth for this order book ladder — here are 5 bid levels: [{price:100,size:10},{price:99,size:20},{price:98,size:15},{price:97,size:25},{price:96,size:30}] — I need to know how much dollar value is available across all those levels.","exampleUseCases":[{"title":"Pre-trade liquidity check for large order","prompt":"I'm about to place a large buy order and need to know how much notional is available in the top 8 ask levels of this order book: [{price:50100,size:2},{price:50105,size:5},{price:50110,size:3},{price:50115,size:8},{price:50120,size:4},{price:50125,size:6},{price:50130,size:1},{price:50135,size:7}] — can you sum up the total depth notional for me?"},{"title":"Risk limit check against available depth","prompt":"Our risk system needs to verify that there's at least $500,000 notional available within the top 5 bid levels before we execute. Here are the levels: [{price:2000,size:50},{price:1999,size:80},{price:1998,size:60},{price:1997,size:40},{price:1996,size:90}]. What's the total depth notional and how many levels were used?"},{"title":"Market impact estimation for algo execution","prompt":"I'm running a VWAP algo and need to know the total notional depth across these 12 ask ladder levels to estimate market impact: [{price:30500,size:10},{price:30510,size:15},{price:30520,size:8},{price:30530,size:20},{price:30540,size:5},{price:30550,size:12},{price:30560,size:7},{price:30570,size:18},{price:30580,size:9},{price:30590,size:14},{price:30600,size:11},{price:30610,size:6}]. Sum up the price times size for all of them."}],"resultDescription":"Returns a deterministic JSON object containing depth_notional (the total sum of price × size across all provided ladder levels) and levels_used (the count of levels included in the calculation). No external data sources are consulted — the math is performed locally on the supplied input array.","failureModes":["Missing or malformed levels array returns an error","Levels array entries missing price or size fields cause computation failure","Empty levels array may return zero notional or an error","Non-numeric price or size values cause validation failure","Payment failure via x402 prevents endpoint access"],"whenToPreferThis":"Choose this endpoint when you have an order book ladder snapshot in memory and need a fast, deterministic, locally-computed notional depth calculation without touching any external market feed, RPC, or API key. Ideal for risk systems, pre-trade checks, and algo execution engines that need reproducible math on caller-supplied data at minimal cost ($0.001 USDC). Prefer over custom implementations when you want auditable, consistent computation without managing the arithmetic yourself.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T01:02:07.658Z","isFirstParty":false}