# x-402 Vision — Image Understanding API

> x-402 Vision — Image Understanding API is a paid API for AI agents from api.x-402.online, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-01).

Answers questions about an image or describes it, accepting a URL or base64 input, and returning a plain-language response from a multimodal AI model with no account or API key required.

## Facts

- Endpoint: GET https://api.x-402.online/v1/vision?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x-402-vision-image-understanding-api-4c47f4e5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__D65f674ZlAUaWLqxklg6

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 x-402-vision-image-understanding-api-4c47f4e5
```

Example prompt: Look at this image — https://example.com/photo.jpg — and tell me what's in it. Is there a dog in the photo?

## When to prefer this

Choose this endpoint when you need pay-per-call image understanding with zero setup — no API key, no account, no subscription. It's ideal for AI agents that encounter images opportunistically and need quick visual Q&A or description without committing to a vision API provider. Prefer it over OpenAI Vision or Google Vision when you want micropayment-based access via the x402 protocol on Base.

## Known failure modes

- Image URL is inaccessible or returns a non-image response, resulting in an error
- Base64 string is malformed or not a supported image format
- Question is ambiguous or unanswerable from the image content alone
- Payment of $0.02 USDC not received, request rejected
- Large or high-resolution images may time out or increase latency

## How this service works

Answer a question about an image, or describe it, from a URL or base64. Image understanding pay-per-call, no account and no API key: send an image URL (or base64) and an optional question, receive a plain-language answer from a multimodal…

## Output

A plain-language text response from a multimodal AI model answering the provided question about the image, or a general description of the image if no question was supplied.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x-402-vision-image-understanding-api-4c47f4e5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.x-402.online](https://www.zero.xyz/host/api.x-402.online/llms.txt)