# Synapse API — Plasma Gas Estimator

> Synapse API — Plasma 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 2026-10-29).

Estimates gas cost for an EVM transaction given to/from/data/value fields across supported blockchain networks

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/plasma/gas/estimate?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-plasma-gas-estimator-d0be4bc8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4ULlPpqfQFEzmk25yU4Yz

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-plasma-gas-estimator-d0be4bc8 -d '<json body>'
```

Example prompt: Estimate the gas needed to send 0.5 ETH from 0xAbC...123 to 0xDeF...456 with no calldata, so I know the fee before I broadcast the transaction.

## When to prefer this

Use this endpoint when you need a quick, pay-per-call gas estimate for an EVM-compatible transaction before broadcasting it, especially when you don't want to run your own node or maintain RPC infrastructure. Prefer this over direct RPC calls when operating in an agentic or serverless context billed per call via x402.

## Known failure modes

- Invalid or malformed address in 'to' or 'from' fields returns an error
- Malformed hex 'data' field causes parsing failure
- Unsupported network or chain context may return an error or zero estimate
- Simulation failure if the transaction would revert on-chain
- Empty or missing required fields may return a validation error

## 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 a gas estimate (typically in gas units) for the described EVM transaction, allowing callers to set appropriate gas limits and estimate transaction fees before broadcasting.

## 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-plasma-gas-estimator-d0be4bc8/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)