# x402engine OpenAI o1 LLM API

> x402engine OpenAI o1 LLM API is a paid API for AI agents from x402engine.app, paid per call via x402, $0.10437/call, status unknown (last checked 2026-10-16).

Runs inference on OpenAI's o1 reasoning model via a pay-per-call HTTP 402 micropayment endpoint, returning an OpenAI-compatible chat completion response.

## Facts

- Endpoint: POST https://x402engine.app/api/llm/o1?utm_source=zero.xyz
- Price: $0.10437/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402engine-openai-o1-llm-api-2009471d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IBNpQv8BY5u_Wfhqqy_rc

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-openai-o1-llm-api-2009471d -d '<json body>'
```

Example prompt: Use the o1 reasoning model to solve this multi-step logic puzzle: 'Three friends A, B, C each have a different pet. A doesn't have the dog. B has the cat. Who has the fish?' — send it as a user message and give me the full reasoning and answer.

## When to prefer this

Choose this endpoint when you need OpenAI's o1 reasoning model specifically — known for strong chain-of-thought, math, coding, and logic tasks — without managing an OpenAI API subscription. Ideal for AI agents that pay per call using USDC on Base, USDm on MegaETH, or USDC on Solana via HTTP 402. Prefer over other LLM endpoints when the task benefits from o1's extended reasoning capabilities rather than speed-optimized models.

## Known failure modes

- Insufficient USDC/crypto balance causes 402 payment failure with no completion returned
- Messages array missing or malformed causes 400 validation error
- Model context window exceeded if messages are too long
- Tool call format mismatch causes incomplete or errored tool_calls in response
- Stream mode may time out if reasoning takes very long
- Unsupported seed value for o1 may be silently ignored

## How this service works

x402engine — OpenAI's reasoning model — excels at math, science, coding, and multi-step problem solving

## Output

Returns an OpenAI-compatible JSON chat completion object containing an array of choices, each with an assistant message (role, content, optional tool_calls), a finish_reason, and the model name (openai/o1). Also includes a top-level content shortcut field with the assistant's text response.

## 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."
      },
      "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."
      },
      "stream": {
       "type": "boolean",
       "description": "Return live OpenAI-compatible SSE after payment settlement."
      },
      "plugins": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "pdf"
        ],
        "properties": {
         "id": {
          "enum": [
           "file-parser"
          ],
          "type": "string"
         },
         "pdf": {
          "type": "object",
          "properties": {
           "engine": {
            "enum": [
             "native"
            ],
            "type": "string"
           }
          }
         }
        }
       },
       "description": "Optional native PDF parser only; automatically enabled for file inputs."
      },
      "messages": {
       "type": "array",
       "items": {
        "type": "object",
        "anyOf": [
         {
          "required": [
           "content"
          ]
         },
         {
          "required": [
           "tool_calls"
          ]
         }
        ],
        "required": [
         "role"
        ],
        "properties": {
         "name": {
          "type": "string"
         },
         "role": {
          "enum": [
           "system",
   
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "model": "openai/o1",
  "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-openai-o1-llm-api-2009471d/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)