# Locus x402 Mistral Chat API

> Locus x402 Mistral Chat API is a paid API for AI agents from mistral.x402.stage.paywithlocus.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Pay-per-use Mistral LLM chat completions endpoint with x402 micropayment billing at $0.001 USDC per call

## Facts

- Endpoint: POST https://mistral.x402.stage.paywithlocus.com/mistral/chat
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/locus-x402-mistral-chat-api-bb45578c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-q1ibMDdlsneAM0Z7B06H

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 locus-x402-mistral-chat-api-bb45578c -d '<json body>'
```

Example prompt: Using the Mistral large model, complete this conversation with temperature 0.7 and a max of 512 tokens — the user asked: 'Summarize the key differences between REST and GraphQL APIs in three bullet points.'

## When to prefer this

Choose this endpoint when you need pay-per-use access to Mistral models (including mistral-large-latest and codestral-latest) without committing to a subscription, billed via x402 USDC micropayments at $0.001 per call. Ideal for agent workflows, low-volume or sporadic inference tasks, or applications where per-call cost accountability matters. Prefer over direct Mistral API when you want automatic micropayment settlement via the x402 protocol rather than managing API keys and monthly billing.

## Known failure modes

- Payment failure: x402 payment authorization rejected if USDC balance insufficient or max_tokens not specified (required for metered billing)
- Invalid model ID: returns error if model string does not match a valid Mistral model (e.g. mistral-large-latest, codestral-latest)
- Missing messages array: request fails without at least one message object in the messages field
- Token limit exceeded: error if max_tokens exceeds model context window
- Rate limiting or staging environment downtime: endpoint is on staging infrastructure and may have lower reliability SLAs
- Malformed tool definitions: tool_choice or tools array with invalid schema causes inference error

## How this service works

Locus public pay-per-use API

## Output

Returns a Mistral chat completion object containing the assistant's reply message, finish reason, usage statistics (prompt/completion tokens), and optionally structured tool call payloads or JSON-formatted output depending on the response_format and tools configured.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "seed": {
   "type": "number"
  },
  "stop": {
   "anyOf": [
    {
     "type": "string"
    },
    {
     "type": "array",
     "items": {}
    }
   ]
  },
  "model": {
   "type": "string"
  },
  "tools": {
   "type": "array",
   "items": {}
  },
  "top_p": {
   "type": "number"
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role"
    ],
    "properties": {
     "name": {
      "type": "string"
     },
     "role": {
      "type": "string"
     },
     "content": {
      "anyOf": [
       {
        "type": "string"
       },
       {
        "type": "array",
        "items": {
         "type": "object",
         "required": [
          "type"
         ],
         "properties": {
          "text": {
           "type": "string"
          },
          "type": {
           "type": "string"
          },
          "image_url": {
           "type": "object",
           "required": [
            "url"
           ],
           "properties": {
            "url": {
             "type": "string"
            }
           },
           "additionalProperties": true
          }
         },
         "additionalProperties": true
        }
       },
       {
        "type": "null"
       }
      ]
     },
     "tool_calls": {
      "type": "array",
      "items": {
       "type": "object",
       "additionalProperties": true
      }
     },
     "tool_call_id": {
      "type": "string"
     }
    },
    "additionalProperties": true
   }
  },
  "max_tokens": {
   "type": "number"
  },
  "temperature": {
   "type": "number"
  },
  "tool_choice": {
   "anyOf": [
    {
     "type": "string"
    },
    {
     "type": "object",
     "additionalProperties": true
    }
   ]
  },
  "response_format": {
   "type": "object",
   "additionalProperties": true
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/locus-x402-mistral-chat-api-bb45578c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mistral.x402.stage.paywithlocus.com](https://www.zero.xyz/host/mistral.x402.stage.paywithlocus.com/llms.txt)