# Polymarket Market Side Volumes API

> Polymarket Market Side Volumes API is a paid API for AI agents from data-selling-api-53234eff36dc.herokuapp.com, paid per call via x402, $0.001000/call, status unknown (last checked 2026-09-15).

Returns buy and sell side volume data for a specified Polymarket prediction market

## Facts

- Endpoint: POST https://data-selling-api-53234eff36dc.herokuapp.com/v1/polymarket/market-side-volumes
- Price: $0.001000/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/data-selling-api-53234eff36dc-herokuapp-com-97dc85fe
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mjisG4DgM8OgIzQZepnID

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 data-selling-api-53234eff36dc-herokuapp-com-97dc85fe -d '<json body>'
```

Example prompt: What are the current buy-side and sell-side volumes for the Polymarket market with ID 0x1234abcd? I want to understand whether there's a directional imbalance in trading activity.

## When to prefer this

Use this endpoint when you need directional volume data (buy vs. sell) for a specific Polymarket prediction market, particularly for analyzing market sentiment, liquidity imbalance, or trading flow. Prefer this over generic market APIs when working specifically with Polymarket data.

## Known failure modes

- Invalid or unknown market ID returns an error or empty result
- Network timeout if Polymarket data is unavailable
- Payment failure (402) if x402 micropayment is not properly attached
- Malformed POST body returns a 400 bad request

## Output

A breakdown of buy-side and sell-side trading volumes for the specified Polymarket market, allowing comparison of directional activity and potential market imbalances.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/data-selling-api-53234eff36dc-herokuapp-com-97dc85fe/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from data-selling-api-53234eff36dc.herokuapp.com](https://www.zero.xyz/host/data-selling-api-53234eff36dc.herokuapp.com/llms.txt)