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Tollbooth Swap Builder
x402
Tollbooth Swap Builder is a paid API for AI agents from tollbooth-production-3845.up.railway.app, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).
Builds an unsigned, fee-inclusive swap transaction for Solana (via Jupiter) or Base (via 0x) that the agent signs and submits with its own wallet
Price / call$0.005
Success—
StatusUnknown
How this service works
Non-custodial swap execution for AI agents on Solana and Base. Pay a small toll to get an unsigned, fee-inclusive swap transaction routed via Jupiter (Solana) or 0x (Base), plus an HMAC-signed receipt for auditing. Comparison-shop first with free indicative quotes at GET /v1/quote (same parameters, no taker required). You sign and submit with your own wallet - Tollbooth never touches keys or funds.
Output
Returns an unsigned swap transaction payload (ready for the agent to sign and submit with its own wallet), a full fee breakdown, routing details (Jupiter or 0x path), and an HMAC-signed receipt for auditing purposes.
Example use cases
Agent rebalancing portfolio on Solana
“My trading agent needs to swap 500 USDC into SOL on Solana right now — build the unsigned Jupiter-routed transaction so the agent can sign and broadcast it with its own wallet.”
Base DeFi swap with audit trail
“Build me a swap transaction to exchange 0.5 ETH for USDC on Base via 0x routing, and include the HMAC receipt so I have an auditable record — my wallet is 0xA1b2...C3d4.”
Pre-trade quote comparison before execution
“Before I commit, build me the actual unsigned swap transaction for 200 USDT to WETH on Base so I can see the full fee-inclusive cost and routing details before my agent signs it.”
Technical details
Endpoint
POSThttps://tollbooth-production-3845.up.railway.app/v1/swap/buildWhen to prefer
Choose this endpoint when your AI agent needs to execute a non-custodial token swap on Solana or Base without surrendering private keys — especially when you need an auditable HMAC receipt, want best-execution routing via Jupiter or 0x, and will sign/submit the transaction yourself. Prefer this over custodial swap APIs or on-chain aggregators you'd call directly when agent-friendly unsigned transaction construction and fee transparency are priorities.
Side effects
- Insufficient liquidity for the requested token pair returns an error with no transaction built
- Unsupported chain or token address returns a 400-level validation error
- Slippage tolerance exceeded causes transaction build failure
- Invalid taker wallet address format returns a validation error
- Network congestion or downstream Jupiter/0x API outage causes a 5xx timeout
- Amount too small to cover fees returns an error indicating minimum thresholds
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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