{"slug":"api-3route-io-v1-chainid-swap-f1b52a","title":"Build an unsigned swap transaction for the best route","host":"api.3route.io","method":"GET","resource":"https://api.3route.io/v1/:chainId/swap","category":"other","description":"Build an unsigned swap transaction for the best route. Builds an unsigned transaction for the selected route. Compare it with a fresh quote, validate every returned transaction field, obtain explicit signing approval, and broadcast it through the selected chain's RPC. For an ERC-20 source, approve t","price_listed":1e-05,"price_asked":null,"state":"effects","state_label":"Not tested: has real-world effects","checks_7d":0,"answered_7d":0,"latency_ms_median":null,"reported_calls_30d":0,"reported_payers_30d":0,"networks":["eip155:42793","eip155:8453","solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"],"badge":"unverified","paid_checks_7d":0,"paid_ok_7d":0,"example_input":{"method":"GET","pathParams":{"chainId":"128064"},"queryParams":{"amount":"1000000000000000000","dst":"0x5fc5360d0400a0fd4f2af552add042d716f1d168","fee":0,"from":"0x1111111111111111111111111111111111111111","gasPrice":"1000000000","includeBlockNumber":false,"includeProtocols":false,"includeTokensInfo":false,"receiver":"0x1111111111111111111111111111111111111111","referrer":"0x1111111111111111111111111111111111111111","slippage":1,"src":"0x0000000000000000000000000000000000000000","usePermit2":false},"type":"http"},"output_schema":{"$schema":"https://json-schema.org/draft/2020-12/schema","properties":{"input":{"additionalProperties":false,"properties":{"method":{"enum":["GET"],"type":"string"},"pathParams":{"additionalProperties":false,"properties":{"chainId":{"description":"Chain ID for the operation.","enum":["4663","42793","128064"],"example":"4663","pattern":"^[0-9]+$","type":"string"}},"required":["chainId"],"type":"object"},"queryParams":{"additionalProperties":false,"properties":{"amount":{"description":"Positive amount of src to sell in smallest units, as an integer string.","example":"1000000000000000000","pattern":"^[0-9]+$","type":"string"},"dst":{"description":"Address of the token being bought; take one from the token-list operation for the selected chain, or use the zero address, or the case-insensitive sentinel 0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee, for the chain's native asset.","example":"0x5fc5360d0400a0fd4f2af552add042d716f1d168","pattern":"^0x[0-9a-fA-F]{40}$","type":"string"},"excludedProtocols":{"type":"string"},"fee":{"default":0,"maximum":3,"minimum":0,"type":"number"},"from":{"description":"Address that signs and sends the transaction, and that the src tokens are taken from","example":"0x1111111111111111111111111111111111111111","pattern":"^0x[0-9a-fA-F]{40}$","type":"string"},"gasPrice":{"example":"1000000000","pattern":"^[0-9]+$","type":"string"},"includeBlockNumber":{"default":false,"type":"boolean"},"includeProtocols":{"default":false,"type":"boolean"},"includeTokensInfo":{"default":false,"type":"boolean"},"permit":{"pattern":"^0x[0-9a-fA-F]*$","type":"string"},"protocols":{"type":"string"},"receiver":{"example":"0x1111111111111111111111111111111111111111","pattern":"^0x[0-9a-fA-F]{40}$","type":"string"},"referrer":{"example":"0x1111111111111111111111111111111111111111","pattern":"^0x[0-9a-fA-F]{40}$","type":"string"},"slippage":{"default":1,"example":1,"maximum":50,"minimum":0,"type":"number"},"src":{"description":"Address of the token being sold; use the zero address, or the case-insensitive sentinel 0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee, for the chain's native asset.","example":"0x0000000000000000000000000000000000000000","pattern":"^0x[0-9a-fA-F]{40}$","type":"string"},"usePermit2":{"default":false,"type":"boolean"}},"required":["src","dst","amount","from"],"type":"object"},"type":{"const":"http","type":"string"}},"required":["type","method"],"type":"object"},"output":{"properties":{"example":{"type":"object"},"type":{"type":"string"}},"required":["type"],"type":"object"}},"required":["input"],"type":"object"},"history":[],"description_full":"Build an unsigned swap transaction for the best route. Builds an unsigned transaction for the selected route. Compare it with a fresh quote, validate every returned transaction field, obtain explicit signing approval, and broadcast it through the selected chain's RPC. For an ERC-20 source, approve the router in tx.to for at least srcAmount before executing the returned transaction, or pass a permit or usePermit2 instead.","last_updated":"2026-09-24T17:32:58.228Z","schemes":["batch-settlement","exact"]}