# NexusAPI AI Similarity

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

Computes semantic similarity between a query string and reference content using AI embeddings

## Facts

- Endpoint: POST https://nexus-api-virid.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/nexusapi-ai-similarity-c8bf96af
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HpUrQpKJqfYH6Nm22j_qg

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 nexusapi-ai-similarity-c8bf96af -d '<json body>'
```

Example prompt: How semantically similar is the sentence 'machine learning improves predictions' to 'AI enhances forecasting accuracy'? Run a similarity check on those two phrases for me.

## When to prefer this

Use this endpoint when you need lightweight, pay-per-call semantic similarity without managing your own embedding infrastructure or API keys. Prefer it for ad-hoc similarity checks in agent workflows where setting up a dedicated embedding service is overkill, or when operating in environments where USDC micropayments via x402 on Base are already supported.

## Known failure modes

- Empty or missing query string returns validation error
- Query too long may exceed token limits and return an error
- Ambiguous or very short queries may produce unreliable similarity scores
- Service downtime on Vercel deployment returns 5xx error
- Insufficient USDC balance causes x402 payment failure before the request is processed

## How this service works

Crypto, AI, Social Media, Finance, Weather, Tools &amp; more. Pay per call in USDC on Base. No API keys.

## Output

Returns a similarity score or ranking indicating how semantically close the input query is to the reference content, likely expressed as a numeric value between 0 and 1 (or equivalent), computed via AI embeddings.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "query": {
   "type": "string",
   "description": "Search query or input parameter"
  }
 }
}
```

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/nexusapi-ai-similarity-c8bf96af/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from nexus-api-virid.vercel.app](https://www.zero.xyz/host/nexus-api-virid.vercel.app/llms.txt)