# Linkrra Synap: gpt-oss-20b Chat Completions

> Linkrra Synap: gpt-oss-20b Chat Completions is a paid API for AI agents from pool.linkrra.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-29).

Serves OpenAI-compatible chat completions for the gpt-oss-20b 20B-parameter model (native MXFP4) with 32K context, billed per-call in USDC on Base via x402 — no API key required.

## Facts

- Endpoint: POST https://pool.linkrra.com/api/billing/x402/models/gpt-oss-20b/chat/completions?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/linkrra-synap-gpt-oss-20b-chat-completions-2c291133
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dZ2URue7BFdb6CFOw8ZIO

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 linkrra-synap-gpt-oss-20b-chat-completions-2c291133 -d '<json body>'
```

Example prompt: Use the gpt-oss-20b model on Linkrra Synap to write me a Python function that parses a CSV file and returns the top 5 rows sorted by the 'revenue' column — stream the response back to me.

## When to prefer this

Choose this endpoint when you need a fast, low-cost general-purpose LLM inference call with no account or API key setup, and your system supports x402 payment in USDC on Base. It is ideal for agentic pipelines that need pay-per-call billing, crypto-native apps, or prototyping scenarios where you want OpenAI-compatible chat completions without a subscription. Prefer it over heavier models (30B+) when latency and cost matter more than maximum capability.

## Known failure modes

- Insufficient USDC balance or failed x402 payment — request rejected before inference begins
- max_tokens exceeds 4096 — validation error returned
- messages array is empty or malformed — 422 validation error
- Model overload or GPU unavailability — 503 or timeout
- Streaming connection dropped mid-response — partial SSE output with no finish_reason

## How this service works

Linkrra Synap: OpenAI gpt-oss-20b (model "gpt-oss-20b") - fast + cheap general model. OpenAI-compatible chat completions for this one model, 32K context, served only on dedicated GPUs we operate, native 4-bit MXFP4. Pay per call in USDC on Base via x402 - no account, no API key. From $0.001 per call, usage-priced per token above that (GET /v1/models). Streaming supported. Product site: https://synap.linkrra.com

## Output

Returns an OpenAI-format chat completion object containing the assistant's generated message, finish reason, and token usage counts. When streaming is enabled, returns OpenAI-compatible Server-Sent Events (SSE) chunks delivered incrementally. The model used is always gpt-oss-20b with up to 32K context and a configurable max_tokens cap (default 4096).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "gpt-oss-20b"
   ],
   "type": "string",
   "description": "Optional: this endpoint always runs gpt-oss-20b."
  },
  "stream": {
   "type": "boolean",
   "default": false,
   "description": "true = stream OpenAI-format Server-Sent Events."
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant",
       "tool"
      ],
      "type": "string"
     },
     "content": {
      "description": "Text, or an array of OpenAI content parts."
     }
    }
   },
   "examples": [
    [
     {
      "role": "user",
      "content": "Write a Python function that reverses a string"
     }
    ]
   ],
   "minItems": 1,
   "description": "OpenAI-format chat history, oldest first: [{role, content}]."
  },
  "max_tokens": {
   "type": "integer",
   "default": 4096,
   "maximum": 4096,
   "minimum": 1,
   "description": "Completion token cap. The price is quoted for the prompt plus this cap."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/linkrra-synap-gpt-oss-20b-chat-completions-2c291133/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pool.linkrra.com](https://www.zero.xyz/host/pool.linkrra.com/llms.txt)