# x402engine Mistral Large 4 LLM API

> x402engine Mistral Large 4 LLM API is a paid API for AI agents from x402engine.app, paid per call via x402, $0.006095/call, status unknown (last checked 2026-10-12).

Provides pay-per-call access to Mistral AI's Mistral Large 4 frontier multimodal model for reasoning, coding, and agentic tasks with a 512K-token context window

## Facts

- Endpoint: POST https://x402engine.app/api/llm/mistral-large-4?utm_source=zero.xyz
- Price: $0.006095/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402engine-mistral-large-4-llm-api-8154f470
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vCDhQy_peOqdD8TOUjOW7

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 x402engine-mistral-large-4-llm-api-8154f470 -d '<json body>'
```

Example prompt: Use Mistral Large 4 to analyze this diagram image and the following codebase context — explain what the architecture does and suggest optimizations, using the full conversation history I'm passing in.

## When to prefer this

Choose this endpoint when you need Mistral AI's Mistral Large 4 specifically — a frontier model with a massive 512K token context window ideal for long documents, complex reasoning, agentic tool-calling, or multimodal (image + text) tasks. It suits pay-per-call agent workflows where you don't want to manage API keys or subscriptions, paying only in USDC per request. Prefer this over OpenAI or Anthropic endpoints when Mistral's reasoning style or licensing is preferred, or when you need the 512K context window that rivals exceed in cost.

## Known failure modes

- Payment not settled — 402 response if USDC micropayment fails
- Invalid messages array — missing required 'role' or 'content'/'tool_calls' field
- Image URL unreachable — multimodal input fails if image_url is inaccessible
- Context length exceeded — inputs surpassing 512K tokens rejected
- Unsupported tool schema — malformed function definitions cause validation errors
- Stream timeout — SSE connection drops on long generations

## How this service works

125 production APIs behind HTTP 402 micropayments. 87 LLMs, Kling V3 and Hailuo video generation, image generation, code execution, travel search, web scraping, TTS, and transaction simulation. Pay with USDC on Base, USDm on MegaETH, or USDC on Solana.

## Output

Returns an OpenAI-compatible JSON response containing the assistant's message content, the finish reason (e.g. 'stop', 'tool_calls'), model identifier, and choice index. Supports streaming via SSE when stream=true, and tool_calls array when the model invokes client-defined functions.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "bodyType",
    "body",
    "method"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "messages"
     ],
     "properties": {
      "seed": {
       "type": "integer",
       "description": "Model-supported seed; see /docs/llm-capabilities.md."
      },
      "stop": {
       "oneOf": [
        {
         "type": "string"
        },
        {
         "type": "array",
         "items": {
          "type": "string"
         },
         "maxItems": 4
        }
       ],
       "description": "Model-supported stop; see /docs/llm-capabilities.md."
      },
      "tools": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "function"
        ],
        "properties": {
         "type": {
          "enum": [
           "function"
          ],
          "type": "string"
         },
         "function": {
          "type": "object",
          "properties": {
           "name": {
            "type": "string"
           },
           "strict": {
            "type": "boolean"
           },
           "parameters": {
            "type": "object"
           },
           "description": {
            "type": "string"
           }
          }
         }
        }
       },
       "description": "Client-executed function definitions; return results using role=tool and tool_call_id."
      },
      "top_p": {
       "type": "number",
       "description": "Model-supported top_p; see /docs/llm-capabilities.md."
      },
      "stream": {
       "type": "boolean",
       "description": "Return live OpenAI-compatible SSE after payment settlement."
      },
      "logprobs": {
       "type": "boolean",
       "description": "Model-supported logprobs; see /docs/llm-capabilities.md."
      },
      "messages": {
       "type": "array",
       "items": {
        "type": "object",
        "anyOf": [
         {
          "required": [
           "content"
          ]
         },
         {
          "required": [
           "tool_calls"
          ]
         }
        ],
        "required": [
         "role"
        ],
        "properties": {
         "name": {
          "type": "string"
         },
         "role": {
          "enum": [
           "system",
           "developer",
           "user",
       
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "model": "mistralai/mistral-large-4-0",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "Hello!"
    },
    "finish_reason": "stop"
   }
  ],
  "content": "Hello!"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402engine-mistral-large-4-llm-api-8154f470/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402engine.app](https://www.zero.xyz/host/x402engine.app/llms.txt)