# Telnyx x402 Gateway – DeepSeek-V4-Flash-0731 Chat Completions

> Telnyx x402 Gateway – DeepSeek-V4-Flash-0731 Chat Completions is a paid API for AI agents from x402.telnyx.com, paid per call via x402, $0.005214/call, status unknown (last checked 2026-10-12).

Generates chat completions using the DeepSeek-V4-Flash-0731 model via Telnyx's x402 pay-per-request USDC gateway

## Facts

- Endpoint: POST https://x402.telnyx.com/v1/chat/completions/_t/deepseek-v4-flash-0731?utm_source=zero.xyz
- Price: $0.005214/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/telnyx-x402-gateway-deepseek-v4-flash-0731-chat-completions-e659d608
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fu_AOivXC3U8-6dMEIIEI

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 telnyx-x402-gateway-deepseek-v4-flash-0731-chat-completions-e659d608 -d '<json body>'
```

Example prompt: Send a chat message to the DeepSeek V4 Flash model through Telnyx and get a completion back — my messages are: system: 'You are a helpful assistant', user: 'Explain quantum entanglement in two sentences', with a max of 300 tokens and temperature 0.7.

## When to prefer this

Choose this endpoint when you need pay-per-call LLM inference with no subscription or API key setup, settling in USDC via x402 micropayment protocol. It is ideal for agents that need cost-controlled, on-demand access to the DeepSeek-V4-Flash-0731 model specifically, with OpenAI-compatible request/response format and tool-calling support up to 16 tools.

## Known failure modes

- Payment rejected or insufficient USDC balance — x402 payment header validation fails
- Messages array exceeds 32 items or content exceeds 32,000 characters — 400 validation error
- max_tokens out of range (must be 1–2048) — 422 unprocessable entity
- temperature out of range (must be 0–2) — 422 validation error
- Tools array exceeds 16 items — schema validation failure
- Model unavailable or Telnyx inference backend down — 503 service unavailable
- Malformed JSON body — 400 bad request

## How this service works

Pay USDC per request for Telnyx Inference and Audio (text-to-speech, speech-to-text) through x402.

## Output

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

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "n": {
   "type": "integer",
   "const": 1,
   "description": "Fixed to one completion per paid call."
  },
  "model": {
   "type": "string",
   "const": "deepseek-ai/DeepSeek-V4-Flash-0731",
   "description": "Model identifier; fixed to deepseek-ai/DeepSeek-V4-Flash-0731 on this route."
  },
  "tools": {
   "type": "array",
   "items": {
    "type": "object"
   },
   "maxItems": 16
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant",
       "tool"
      ],
      "type": "string"
     },
     "content": {
      "type": "string",
      "maxLength": 32000
     }
    }
   },
   "maxItems": 32,
   "description": "OpenAI-style chat messages."
  },
  "max_tokens": {
   "type": "integer",
   "maximum": 2048,
   "minimum": 1
  },
  "temperature": {
   "type": "number",
   "maximum": 2,
   "minimum": 0
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "chatcmpl-xxx",
  "usage": {
   "total_tokens": 16,
   "prompt_tokens": 12,
   "completion_tokens": 4
  },
  "object": "chat.completion",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "Hello!"
    },
    "finish_reason": "stop"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/telnyx-x402-gateway-deepseek-v4-flash-0731-chat-completions-e659d608/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.telnyx.com](https://www.zero.xyz/host/x402.telnyx.com/llms.txt)