# Synapse API — Humanity Token Balances

> Synapse API — Humanity 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 2026-10-29).

Fetches token balances for a given wallet address across specified ERC-20 contract addresses on blockchain networks

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/humanity/token/balances?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-humanity-token-balances-50bfb9f2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yXYUILnBDrtMCczlRiqRW

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-humanity-token-balances-50bfb9f2 -d '<json body>'
```

Example prompt: What's the token balance for wallet 0xAbc123...def for these contracts: 0xToken1... and 0xToken2...?

## When to prefer this

Choose this endpoint when you need to look up ERC-20 token balances for a specific wallet address against one or more contract addresses, particularly in automated DeFi portfolio tracking, wallet auditing, or token distribution verification workflows. It is pay-per-call via x402/USDC micropayment, making it cost-effective for on-demand lookups rather than bulk historical queries.

## Known failure modes

- Invalid or malformed wallet address returns an error or empty result
- Non-existent contract address may return zero balance or an error
- Network unavailability on the target blockchain results in a timeout or 503
- Missing required 'owner' field causes a 400 bad request
- Empty contractAddresses array may return an empty result set

## 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 token balances associated with the specified owner wallet address for each provided contract address, including amounts held per token contract.

## 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-humanity-token-balances-50bfb9f2/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)