# Surplus Intelligence Open Market AI Inference Completions

> Surplus Intelligence Open Market AI Inference Completions is a paid API for AI agents from www.surplusintelligence.ai, paid per call via x402, $0.003315/call, status unknown (last checked 2026-09-13).

Runs LLM chat completions via an open order book marketplace that routes to the cheapest available AI model provider, offering up to 90% off list prices.

## Facts

- Endpoint: POST https://www.surplusintelligence.ai/api/inference/v1/completions
- Price: $0.003315/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/surplus-intelligence-open-market-ai-inference-completions-ef55f787
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fK7u6AQvJIti-0Jw1KHK2

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 surplus-intelligence-open-market-ai-inference-completions-ef55f787 -d '<json body>'
```

Example prompt: Use Surplus Intelligence to send this message to llama-3.3-70b: 'Explain the concept of arbitrage in two sentences' — keep it under 100 tokens and don't stream.

## When to prefer this

Choose this endpoint when cost is the primary concern and you want the cheapest available inference across multiple model providers at the time of the call. Ideal for high-volume, price-sensitive workloads using popular open or proprietary models (Llama, GPT, Claude) where slight provider variation is acceptable. Best suited for agents that use x402 micropayment flows and want per-call billing without subscriptions.

## Known failure modes

- Model not available or delisted from order book — 404 or model-not-found error
- Insufficient USDC balance or x402 payment failure — 402 Payment Required
- Malformed messages array or missing required fields — 400 Bad Request
- max_tokens exceeded context window for chosen model — 400 or truncation
- Rate limiting or order book congestion — 429 Too Many Requests
- Model provider outage causing inference failure — 503 Service Unavailable

## How this service works

Buy the cheapest inference. Sell your credits. The open order book for AI models. Up to 90% off GPT-5.5, Claude Opus 4.8, and more.

## Output

Returns a JSON object in OpenAI-compatible chat.completion format, including the assistant's reply message, finish reason (e.g. 'stop'), and token usage breakdown (prompt tokens, completion tokens, total tokens), plus a completion ID.

## Example request

```json
{
 "model": "llama-3.3-70b",
 "prompt": "Explain the concept of arbitrage in two sentences",
 "stream": false,
 "max_tokens": 100
}
```

## 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": {
     "required": [
      "model",
      "messages"
     ],
     "properties": {
      "model": {
       "type": "string",
       "description": "Surplus Intelligence model id. Call /v1/models for available models."
      },
      "stream": {
       "type": "boolean"
      },
      "messages": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "role",
         "content"
        ],
        "properties": {
         "role": {
          "enum": [
           "system",
           "developer",
           "user",
           "assistant",
           "tool"
          ],
          "type": "string"
         },
         "content": {}
        },
        "additionalProperties": true
       },
       "minItems": 1,
       "description": "OpenAI-compatible chat messages."
      },
      "max_tokens": {
       "type": "integer",
       "minimum": 1,
       "description": "Maximum output tokens."
      },
      "temperature": {
       "type": "number",
       "maximum": 2,
       "minimum": 0
      }
     },
     "additionalProperties": true
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "id",
      "object",
      "choices"
     ],
     "properties": {
      "id": {
       "type": "string"
      },
      "usage": {
       "type": "object"
      },
      "object": {
       "type": "string"
      },
      "choices": {
       "type": "array"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "chatcmpl_surplus_example",
  "usage": {
   "total_tokens": 18,
   "prompt_tokens": 12,
   "completion_tokens": 6
  },
  "object": "chat.completion",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "Hello from Surplus Intelligence."
    },
    "finish_reason": "stop"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/surplus-intelligence-open-market-ai-inference-completions-ef55f787/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.surplusintelligence.ai](https://www.zero.xyz/host/www.surplusintelligence.ai/llms.txt)