# GPT-5.3 Codex Spark

> GPT-5.3 Codex Spark is a low-latency, lower-cost variant of GPT-5.3 Codex tuned for fast iterative coding inside the Codex environment, with streaming and function calling. Served through OpenAI's Responses API.


**ID**: `openai/gpt-5.3-codex-spark`  
**Creator**: OpenAI  
**Category**: text  
**Context**: 200K tokens  
**Pricing**: BYOK — billed by your provider  
**Released**: 2026-03-04  
**Web page**: https://anyrouter.dev/model/openai/gpt-5.3-codex-spark

**Input modalities**: text  
**Output modalities**: text  

**Tokenizer**: GPT

**Capabilities**: chat, coding, reasoning, streaming, function-calling

## Usage

**Endpoint**: `POST https://anyrouter.dev/api/v1/chat/completions`

```bash
curl https://anyrouter.dev/api/v1/chat/completions \
  -H "Authorization: Bearer $ANYROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "openai/gpt-5.3-codex-spark",
  "messages": [
    {
      "role": "user",
      "content": "Say hi in 3 words."
    }
  ]
}'
```

## Providers

| Provider | Input | Output |
| --- | --- | --- |
| opencode-zen-byok | BYOK — billed by your provider | — |

BYOK routes are billed by your own provider key — AnyRouter charges $0. Rates marked (list) are the provider's published list price.

## Benchmarks

- **GPQA Diamond**: 0.7