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Synapse API — StarkNet Gas Estimator
x402
Synapse API — StarkNet Gas Estimator is a paid API for AI agents from synapse-api-brown.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).
Estimates gas fees for a transaction on the StarkNet blockchain given sender, recipient, calldata, and value
Price / call$0.01
Success—
StatusUnknown
How this service works
High-speed API suite for AI processing, web scraping, and smart data utilities across 57+ blockchain networks. Pay-per-call via x402.
Output
Returns an estimated gas amount (and likely fee in the StarkNet native fee token) required to execute the described transaction on the StarkNet network, allowing the caller to budget fees before broadcasting.
Example use cases
Pre-flight transaction cost check
“Before I send this StarkNet contract call, can you estimate how much gas it will use? The sender is 0xABC...123, the recipient contract is 0xDEF...456, and the calldata is 0xdeadbeef with zero ETH value.”
DeFi trade gas optimization
“I want to swap tokens on a StarkNet DEX — can you estimate the gas fee for a transaction from my wallet 0x111...AAA to the swap contract 0x222...BBB with calldata 0xcafebabe and value 0x0 so I know if it's worth it right now?”
Smart contract deployment cost estimate
“How much gas would it cost to call this StarkNet smart contract at 0x333...CCC from address 0x444...DDD with the following calldata: 0xabcdef01 and no ETH value attached?”
Technical details
Endpoint
POSThttps://synapse-api-brown.vercel.app/api/starknet/gas/estimateWhen to prefer
Use this endpoint when you need a quick, pay-per-call gas estimate specifically for StarkNet (a ZK-rollup L2) transactions without setting up your own StarkNet node or RPC provider. Prefer it over generic Ethereum gas estimators when the target chain is StarkNet.
Side effects
- Invalid or malformed address in 'to' or 'from' fields returns an error
- Malformed calldata string causes parsing failure
- StarkNet node unavailability causes a timeout or 503
- Transaction simulation failure if the contract call would revert
- Missing required fields returns a 400 bad request
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| to | string | |
| data | string | |
| from | string | |
| value | string |
Tags
x402
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