{"uid":"cap_EC0W-1IZr433Q-GRikh9w","slug":"base-dex-slippage-price-impact-simulator-e827a39a","name":"Base DEX Slippage & Price Impact Simulator","description":"What a trade size actually executes at on Base, simulated against live reserves. Returns best (venue, amountOut, executionPrice, priceImpactBps, feeBps, totalCostBps), routingGain, venues[]. Requires ?pair=SYM/SYM AND ?amountUsd=25000 (or ?amountIn=). pair alone = 400 missing_amount. Errors: 400 bad_pair|missing_amount|bad_amount, 404 no_pools|no_quote|cannot_size_in_usd, 502 upstream_read_failed. Spot price without a size is /price. Chain-pinned; bare /slippage = BSC.","url":"https://x402.donnyautomation.com/base/slippage","method":"GET","headers":{},"bodySchema":{"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"],"type":"string"},"queryParams":{"type":"object","required":["pair","amountUsd"],"properties":{"pair":{"type":"string","description":"Token pair as SYM/SYM on Base (e.g. WETH/USDC)."},"amountIn":{"type":"string","description":"Trade size denominated in the FIRST pair symbol instead of USD. An alternative to amountUsd; supplying either one is enough."},"amountUsd":{"type":"string","description":"Trade size in USD, e.g. 10000. Required unless amountIn is given instead."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"ts":"2026-07-31T00:00:00.000Z","chainId":8453,"network":"base"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_zpKaK-QhHAQhQAZyQG6xM","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Simulates a swap on Base L2 across BaseSwap, SushiSwap, and Uniswap v3 to return best execution venue, amount out, price impact in basis points, pool fee, and savings vs naive routing for a given trade size.","exampleAgentPrompt":"Before I swap 10 WETH for USDC on Base, can you simulate the trade across BaseSwap, SushiSwap, and Uniswap v3 and tell me which venue gives the best execution, how much USDC I'd actually receive, and what the price impact is in basis points?","exampleUseCases":[{"title":"Pre-trade slippage check for trading bot","prompt":"My trading bot is about to execute a WETH/USDC swap on Base — can you simulate the trade and tell me the price impact in bps, the best venue, and how much I'd actually get out before I fire the transaction?"},{"title":"Large trade impact assessment","prompt":"I'm about to make a big WBTC/USDC trade on Base and I'm worried about slippage — can you run a simulation across all the Base DEXs and tell me the price impact and which pool gives me the best fill?"},{"title":"DEX aggregator routing decision","prompt":"For my DEX aggregator on Base L2, check the WETH/USDC pair and tell me which of BaseSwap, SushiSwap, or Uniswap v3 gives the best execution right now, including the pool fee and how much routing optimization saves versus just picking the best quoted price."}],"resultDescription":"Returns the best execution venue (BaseSwap, SushiSwap, or Uniswap v3), the expected amount out for the trade, price impact in basis points, the pool fee tier, and the savings in value achieved by optimal routing versus the naive best-quoted-price approach — all computed against live on-chain AMM reserves on Base L2.","failureModes":["Invalid or unsupported token pair symbol returns an error — only Base L2 tokens supported","Pair not listed on any of the three supported DEXs returns no results or an empty venue list","Extremely low liquidity pools may return unreliable or extreme price impact values","Network congestion or RPC errors on Base may cause stale or failed reserve reads","Malformed pair format (not SYM/SYM) results in a schema validation error"],"whenToPreferThis":"Choose this endpoint when you need pre-trade execution quality data specifically on Base L2 / Coinbase L2 and want a multi-venue comparison across BaseSwap, SushiSwap, and Uniswap v3 in a single call. It is superior to a simple spot price lookup when trade size matters and slippage/price impact is a concern. Prefer this over generic price APIs when running a trading bot, building a DEX aggregator, or performing pre-trade risk checks on Base.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T00:45:28.595Z","isFirstParty":false}