# OmniAPI AI Similarity

> OmniAPI AI Similarity is a paid API for AI agents from omni-api-cyan.vercel.app, paid per call via x402, $0.087051/call, status unknown (last checked 2026-09-14).

Computes semantic similarity between a query text and input data, returning a similarity score or ranked results

## Facts

- Endpoint: POST https://omni-api-cyan.vercel.app/api/ai/similarity
- Price: $0.087051/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/omniapi-ai-similarity-50cf8095
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_hAKtVawjmJaoibfAAoXXs

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 omniapi-ai-similarity-50cf8095 -d '<json body>'
```

Example prompt: Can you check how semantically similar the text 'machine learning accelerates drug discovery' is to the query 'AI in pharmaceutical research' and give me a similarity score?

## When to prefer this

Choose this endpoint when you need a pay-per-call, no-subscription semantic similarity computation that works within a crypto-native x402 payment flow. Best for agents already operating in the OmniAPI ecosystem or when you need lightweight on-demand similarity scoring without standing up a dedicated embedding service.

## Known failure modes

- Missing required 'query' field returns validation error
- Empty or very short query strings may produce unreliable scores
- Payment failure via x402 results in 402 response before processing
- Extremely long input texts may be truncated or rejected
- Non-English or multilingual text may yield degraded similarity accuracy

## How this service works

444 endpoints across 9+ chains. Crypto, AI, Social, Finance, Weather, Tools. Pay per call in USDC via x402 with 4 facilitators: Dexter, Meridian, FluxA, GoPlausible.

## Output

Returns a similarity score or ranked relevance results comparing the query text against the provided input, likely including a numerical score (0-1) and possibly additional metadata about the match quality.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "query"
 ],
 "properties": {
  "input": {
   "type": "string",
   "description": "Input data for the endpoint"
  },
  "query": {
   "type": "string",
   "description": "Search query or input text"
  },
  "params": {
   "type": "object",
   "description": "Additional parameters"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "description": "API response data"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/omniapi-ai-similarity-50cf8095/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from omni-api-cyan.vercel.app](https://www.zero.xyz/host/omni-api-cyan.vercel.app/llms.txt)