# Polymarket Midpoint Prices

> Polymarket Midpoint Prices is a paid API for AI agents from AIsa MPP Data APIs at api.aisa.one, paid per call via MPP, $0.012/call, status unknown (last checked 2026-10-18).

Retrieves midpoint prices (average of best bid and best ask) for one or more Polymarket prediction market token IDs.

## Facts

- Endpoint: GET https://api.aisa.one/apis/v1/polymarket/midpoints?utm_source=zero.xyz
- Price: $0.012/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Provider: AIsa MPP Data APIs
- Website: https://aisa.one
- Tags: web-search, financial-data, prediction-markets, weather, travel, data, search
- Canonical page: https://www.zero.xyz/c/aisa-mpp-data-apis-polymarket-midpoint-prices-5713d7c8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_swOFRGz4e7qc9jDXOjBYG

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 aisa-mpp-data-apis-polymarket-midpoint-prices-5713d7c8
```

Example prompt: What are the current midpoint prices for Polymarket tokens 12345,67890,11223? I want the average of the best bid and ask for each one.

## When to prefer this

Use this endpoint when you need real-time fair-value pricing for Polymarket prediction market tokens, especially when querying multiple tokens in a single call. Prefer this over individual price lookups when you need batch midpoint calculations. It is ideal for monitoring implied probabilities, building dashboards, or running arbitrage detection across correlated outcomes.

## Known failure modes

- Invalid or malformed token IDs return missing keys or errors in the response map
- Tokens with no active order book may return null or zero midpoint
- Rate limiting or payment failures result in 402/429 errors
- Very large lists of token IDs may cause request timeouts
- Token IDs for expired or resolved markets may return stale or unavailable prices

## How this service works

Retrieves midpoint prices for multiple token IDs using query parameters. The midpoint is calculated as the average of the best bid and best ask prices.

<!-- aisa-pricing:start -->
Published reference price: $0.012 USD per successful request. Account-specific pricing and final settlement may differ.
<!-- aisa-pricing:end -->

## Output

A JSON object mapping each requested token ID (as a string key) to its current midpoint price (as a string value), where the midpoint is the arithmetic mean of the best bid and best ask prices on Polymarket for that token.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "token_ids"
 ],
 "properties": {
  "token_ids": {
   "type": "string",
   "description": "Comma-separated list of token IDs"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "description": "Map of token ID to midpoint price",
 "additionalProperties": {
  "type": "string"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/aisa-mpp-data-apis-polymarket-midpoint-prices-5713d7c8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.aisa.one](https://www.zero.xyz/host/api.aisa.one/llms.txt)