# Model Access Gateway – Gemini 2.0 Flash Chat Completions (x402)

> Model Access Gateway – Gemini 2.0 Flash Chat Completions (x402) is a paid API for AI agents from modelaccessgateway.com, paid per call via x402, $0.0014/call, status unknown (last checked 2026-10-17).

OpenAI-compatible chat completions via Google Gemini 2.0 Flash, paid per call in USDC on Base using the x402 protocol — no account or API key required.

## Facts

- Endpoint: POST https://modelaccessgateway.com/llm/gemini-3.8-flash?utm_source=zero.xyz
- Price: $0.0014/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/model-access-gateway-gemini-2-0-flash-chat-completions-x402-e881580d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nwc66EU2RHu866FA1mOGe

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 model-access-gateway-gemini-2-0-flash-chat-completions-x402-e881580d -d '<json body>'
```

Example prompt: Send this conversation to Gemini Flash — system prompt 'You are a helpful assistant', user message 'Summarize the benefits of compound interest in three bullet points' — keep the response under 300 tokens and pay the $0.0014 USDC fee per call.

## When to prefer this

Choose this endpoint when you need fast, cheap Gemini Flash inference without any Google account, API key, or subscription — ideal for autonomous agents that hold USDC on Base and want per-call micropayment billing via x402. Prefer it over standard Google AI Studio or OpenAI when you want anonymous, accountless access, crypto-native payment, and OpenAI SDK compatibility. The automatic refund on model failure makes it low-risk for automated pipelines.

## Known failure modes

- Insufficient USDC balance or x402 payment failure — call rejected before inference runs
- Model unavailable or overloaded — automatic refund issued, no content returned
- Invalid messages array (empty or missing role field) — 400 validation error
- max_tokens exceeds 16384 — rejected with schema validation error
- Temperature out of range (0–2) — parameter rejected
- Malformed response_format object — may cause generation error or unexpected output

## How this service works

LLM inference API: OpenAI-compatible chat completions for 136 AI models (Claude, GPT, Gemini, Grok, DeepSeek, Qwen, Kimi, GLM), paid per call in USDC on Base with x402. No account, no API key, automatic refund if the model fails.

## Output

Returns an OpenAI-compatible chat.completion JSON object containing the assistant's message content, finish reason (e.g. 'stop'), token usage breakdown (prompt, completion, total), model name, completion ID, and created timestamp. If streaming is enabled, server-sent events are returned token by token after the x402 payment is processed. If the model fails, an automatic USDC refund is issued.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "type": "string",
   "description": "Optional: fixed by the route (google/gemini-3.8-flash)"
  },
  "tools": {
   "type": "array"
  },
  "stream": {
   "type": "boolean",
   "description": "true: server-sent events after payment"
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant",
       "tool",
       "developer"
      ],
      "type": "string"
     },
     "content": {
      "type": [
       "string",
       "array",
       "null"
      ]
     }
    }
   },
   "minItems": 1
  },
  "max_tokens": {
   "type": "integer",
   "maximum": 16384,
   "minimum": 1,
   "description": "Optional, default 4096"
  },
  "temperature": {
   "type": "number",
   "maximum": 2,
   "minimum": 0
  },
  "response_format": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "chatcmpl-7f3c2a91",
  "model": "google/gemini-3.8-flash",
  "usage": {
   "total_tokens": 10,
   "prompt_tokens": 9,
   "completion_tokens": 1
  },
  "object": "chat.completion",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "OK"
    },
    "finish_reason": "stop"
   }
  ],
  "created": 1791979200
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/model-access-gateway-gemini-2-0-flash-chat-completions-x402-e881580d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from modelaccessgateway.com](https://www.zero.xyz/host/modelaccessgateway.com/llms.txt)