# Synapse API — Polygon Token Balances

> Synapse API — Polygon Token Balances 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 2026-10-13).

Retrieves ERC-20 token balances for a given wallet address on the Polygon network, optionally filtered by specific contract addresses

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/polygon/token/balances?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-polygon-token-balances-e9596486
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cdF8NBGdMbC10keTbJfp8

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-polygon-token-balances-e9596486 -d '<json body>'
```

Example prompt: What are all the ERC-20 token balances for wallet 0xAbC1234...5678 on Polygon? Also check the balance for USDC contract 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48 specifically.

## When to prefer this

Choose this endpoint when you need to look up ERC-20 token balances specifically on the Polygon (MATIC) network. It is ideal for DeFi portfolio tracking, verifying token transfers, auditing wallet holdings, or checking specific contract balances on Polygon. Prefer this over Ethereum mainnet equivalents when the target chain is Polygon, and over general multi-chain solutions when you only need Polygon data at low per-call cost ($0.01 USDC).

## Known failure modes

- Invalid or malformed wallet address returns an error or empty result
- Non-existent or invalid contract address may return zero balance or error
- Rate limiting or payment failure (x402) returns 402 Payment Required
- Polygon RPC node downtime may cause timeouts or 503 errors
- Address with no token holdings returns an empty balances array

## 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 list of ERC-20 token balances associated with the given wallet address on the Polygon network, including token contract addresses, token symbols, decimals, and balance amounts. If specific contract addresses are provided, results are filtered to those tokens only.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "owner": {
   "type": "string"
  },
  "contractAddresses": {
   "type": "array",
   "items": {
    "type": "string"
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synapse-api-polygon-token-balances-e9596486/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)