# x402engine Qwen3.7-Plus LLM API

> x402engine Qwen3.7-Plus LLM API is a paid API for AI agents from x402engine.app, paid per call via x402, $0.009663/call, status unknown (last checked 2026-10-18).

Runs inference on Alibaba's Qwen3.7-Plus large language model via pay-per-call HTTP 402 micropayment, returning OpenAI-compatible chat completions.

## Facts

- Endpoint: POST https://x402engine.app/api/llm/qwen3.7-plus?utm_source=zero.xyz
- Price: $0.009663/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402engine-qwen3-7-plus-llm-api-511d2416
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0jCRfuK3pa5qmUcyKJsn-

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-qwen3-7-plus-llm-api-511d2416 -d '<json body>'
```

Example prompt: Ask Qwen3.7-Plus to explain the differences between REST and GraphQL APIs — send it as a user message and stream the response back to me.

## When to prefer this

Choose this endpoint when you need Qwen3.7-Plus specifically — a model strong in multilingual (especially Chinese/English) tasks, coding, and reasoning — and want pay-per-call pricing via USDC micropayment rather than a monthly subscription. Prefer this over OpenAI or Anthropic endpoints when cost-per-call transparency matters, when you need Qwen's particular multilingual strengths, or when you want to avoid vendor lock-in with a usage-based model that supports OpenAI-compatible tool calling and streaming.

## Known failure modes

- Payment not settled — 402 response if USDC/USDm payment header is missing or insufficient
- Invalid messages array — 400 if required 'messages' field is absent or malformed
- Unsupported parameter — model may ignore or error on top_k/logprobs if not supported (see /docs/llm-capabilities.md)
- Context length exceeded — model returns error if combined prompt exceeds token limit
- Tool call schema invalid — malformed function definition causes 400 or unexpected behavior
- Streaming timeout — SSE stream may drop if network is unstable after payment settles

## How this service works

x402engine — Alibaba's cost-effective Qwen 3.7 model — 1M context with strong coding and multilingual support

## Output

An OpenAI-compatible JSON object containing the model name ('qwen/qwen3.7-plus'), a choices array with the assistant's message (role, content, tool_calls if applicable), finish_reason ('stop', 'tool_calls', etc.), and a top-level content shortcut field. If streaming is enabled, returns SSE chunks in OpenAI format.

## 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_k": {
       "type": "integer",
       "description": "Model-supported top_k; see /docs/llm-capabilities.md."
      },
      "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": "
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "model": "qwen/qwen3.7-plus",
  "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-qwen3-7-plus-llm-api-511d2416/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)