# Telnyx Inference GLM-5.3-Flash (upto/metered)

> Telnyx Inference GLM-5.3-Flash (upto/metered) is a paid API for AI agents from x402.telnyx.com, paid per call via x402, $0.043205/call, status unknown (last checked 2026-10-15).

OpenAI-compatible chat completions using ZAI's GLM-5.3-Flash model via Telnyx Inference, billed per-token up to a cap (upto scheme) for large-context workloads.

## Facts

- Endpoint: POST https://x402.telnyx.com/v1/chat/completions/_t/glm-5.3-flash/upto?utm_source=zero.xyz
- Price: $0.043205/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/telnyx-inference-glm-5-3-flash-upto-metered-6ec8a09d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IZqjBp9HCI75RiGS2ePrJ

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-inference-glm-5-3-flash-upto-metered-6ec8a09d -d '<json body>'
```

Example prompt: Using Telnyx's GLM-5.3-Flash model, send this conversation history and answer the user's question: 'What are the main differences between REST and GraphQL?' — keep the response under 1024 tokens.

## When to prefer this

Choose this endpoint when you need a fast, low-cost chat completion with metered (per-token) billing on large-context workloads using GLM-5.3-Flash. Ideal for agentic pipelines that may have variable prompt sizes and want to avoid overpaying for short completions. Prefer over the flat-rate GLM route when context is large and unpredictable. The OpenAI-compatible interface makes it a drop-in replacement for existing OpenAI SDK integrations.

## Known failure modes

- Payment failure or insufficient USDC balance — HTTP 402 returned before inference runs
- max_tokens out of range (must be 512–4096) — validation error
- messages array empty or malformed role/content — HTTP 400
- Model overloaded or unavailable — HTTP 503 or timeout
- Context too large (over 900,000 chars per message or 32 messages) — truncation or 400 error

## How this service works

Featured model. Chat completions via Telnyx Inference (zai-org/GLM-5.3-Flash), run at low reasoning effort for direct answers. max_tokens must be 512–2048 (omit it for the 1024-token default). OpenAI-compatible. $0.005783 USDC per call, or pay per-token via the upto scheme. (upto metered — large context)

## Output

An OpenAI-compatible chat completion response containing the assistant's generated message, finish reason, and token usage counts (prompt tokens, completion tokens, total tokens). Returns exactly one completion (n=1) per call.

## 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": "zai-org/GLM-5.3-Flash",
   "description": "Model identifier; fixed to zai-org/GLM-5.3-Flash 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": 900000
     }
    }
   },
   "maxItems": 32,
   "description": "OpenAI-style chat messages."
  },
  "max_tokens": {
   "type": "integer",
   "maximum": 4096,
   "minimum": 512
  },
  "temperature": {
   "type": "number",
   "maximum": 2,
   "minimum": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/telnyx-inference-glm-5-3-flash-upto-metered-6ec8a09d/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)