# Synapse API — Abstract Token Balances

> Synapse API — Abstract 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 2026-09-15).

Retrieves token balances for a given wallet address across specified ERC-20 or native token contract addresses on Abstract (or supported blockchain networks)

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/abstract/token/balances
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-abstract-token-balances-975703a2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lfmWBqA_Hrnp0QlaYQ2cZ

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-abstract-token-balances-975703a2 -d '<json body>'
```

Example prompt: Can you check the token balances for wallet address 0xAbC123...def and these two contract addresses: 0xToken1... and 0xToken2...?

## When to prefer this

Choose this endpoint when you need to look up on-chain token balances for a specific wallet across one or more ERC-20 or native token contracts, especially when operating in an agent pipeline that supports x402 pay-per-call micropayments. Prefer this over general blockchain explorers when you need programmatic, API-level access to balance data without scraping.

## Known failure modes

- Invalid or malformed owner address returns an error or empty result
- Unsupported contract address returns null or zero balance
- Rate limiting or payment failure (x402) returns a 402 Payment Required response
- Network timeout if the underlying blockchain node is slow
- Empty contractAddresses array may return no results or an 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 structured list of token balances for the specified wallet owner address, keyed by each provided contract address, including balance amounts and potentially token metadata such as symbol and decimals.

## 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-abstract-token-balances-975703a2/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)