OpenAI

GPT-5.3 Codex

OpenAI's 2025 code-specialized model, focused on code understanding, generation, and optimization with caching support

Category Text Model ID gpt-5.3-codex

Context Length256K tokens

Model TypeCode-Specialized Model

Key FeaturesCode Understanding, Generation, Debugging, Optimization

Pricing & Specs

💰 Pricing

Input$1.75 / M tokens

Output$14 / M tokens

Cache Hit$0.175 / M tokens

⚙️ Specs

Context Length256K tokens

Model TypeCode-Specialized Model

Key FeaturesCode Understanding, Generation, Debugging, Optimization

Caching SupportSupports Prompt Caching Acceleration

Knowledge CutoffJune 2025

API CompatibilityOpenAI API, Codex CLI

API Examples

Python (OpenAI SDK)

from openai import OpenAI

client = OpenAI(
    api_key="your-api-key",
    base_url="https://api.xairouter.com/v1"
)

response = client.chat.completions.create(
    model="gpt-5.3-codex",
    messages=[
        {"role": "user", "content": "Write a quicksort function in Python"}
    ]
)

print(response.choices[0].message.content)

cURL (OpenAI API)

curl https://api.xairouter.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-5.3-codex",
    "messages": [
      {"role": "user", "content": "Write a quicksort function in Python"}
    ]
  }'

Developer Assist

# Configure ~/.codex/config.toml
cat > ~/.codex/config.toml << 'EOF'
model_provider = "xai"
model = "gpt-5.4"
model_reasoning_effort = "xhigh"
plan_mode_reasoning_effort = "xhigh"
model_reasoning_summary = "none"
model_verbosity = "medium"
model_context_window = 1050000
model_auto_compact_token_limit = 945000
tool_output_token_limit = 6000
approval_policy = "never"
sandbox_mode = "danger-full-access"
suppress_unstable_features_warning = true

[model_providers.xai]
name = "OpenAI"
base_url = "https://api.xairouter.com"
wire_api = "responses"
requires_openai_auth = false
env_key = "XAI_API_KEY"

[features]
multi_agent = true

[agents]
max_threads = 4
max_depth = 1
job_max_runtime_seconds = 1800
EOF

# Set environment variable (add to ~/.bashrc or ~/.zshrc)
export XAI_API_KEY="sk-Xvs..."

# Launch Codex CLI
codex

← Back to Models