# Synapse API — Aptos Gas Estimator

> Synapse API — Aptos 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 2026-09-13).

Estimates the gas cost for a transaction on the Aptos blockchain given sender, recipient, value, and calldata

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/aptos/gas/estimate
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-aptos-gas-estimator-c4cd2c9c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_darHYVrv0wZ25F7MdxxO_

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability synapse-api-aptos-gas-estimator-c4cd2c9c -d '<json body>'
```

Example prompt: Estimate the gas fees for an Aptos transaction from my wallet 0xABC123 to 0xDEF456 with a value of 100 APT and no calldata.

## When to prefer this

Use this endpoint when you need a quick, pay-per-call gas estimate for an Aptos-specific transaction without running your own Aptos node. Preferable over generic blockchain gas estimators when you are specifically working on the Aptos network and need low-latency pre-flight fee checks.

## Known failure modes

- Invalid or malformed address fields return a 400 error
- Unsupported or invalid calldata format causes estimation failure
- Network connectivity issues to Aptos RPC nodes may cause timeouts
- Missing required fields (from/to) result in validation errors
- Value field with non-numeric or improperly formatted strings may fail parsing

## 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 cost for the specified Aptos transaction, including the computed fee in native units, allowing callers to budget transaction costs before submission.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "to": {
   "type": "string"
  },
  "data": {
   "type": "string"
  },
  "from": {
   "type": "string"
  },
  "value": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synapse-api-aptos-gas-estimator-c4cd2c9c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from synapse-api-brown.vercel.app](https://www.zero.xyz/host/synapse-api-brown.vercel.app/llms.txt)