OpenClaw With GPT-4 and GPT-5: OpenAI API Setup Guide [2026]

OpenAI's GPT models are a popular choice for powering OpenClaw. If you are already familiar with ChatGPT or have an existing OpenAI account, using GPT as your LLM backend is a natural choice. OpenClaw supports the full range of OpenAI models, including GPT-4o, GPT-4o Mini, and GPT-5.

This guide covers the complete setup process, model selection guidance, and tips for optimizing your GPT-powered OpenClaw deployment.

What Does the OpenAI Integration Do?

The OpenAI integration provides the "brain" behind your OpenClaw agent. When you send a message through WhatsApp, Telegram, or any other channel, OpenClaw sends it to the GPT API for processing. GPT generates a response, decides which tools to call, and OpenClaw executes the actions.

• Function calling — GPT decides which tools to use based on your request
• Streaming responses — real-time response generation for lower perceived latency
• Vision support — GPT-4o and GPT-5 can process images sent through messaging channels
• JSON mode — structured output for reliable data extraction
• Multi-model routing — use different GPT models for different task types

What Do You Need Before Starting?

• A running OpenClaw instance
• An OpenAI platform account at platform.openai.com
• A payment method added to your OpenAI account
• API credits (new accounts typically start with $5 free credits)

How Do You Configure GPT With OpenClaw?

Step 1 — Get your API key

Go to platform.openai.com/api-keys and create a new secret key. Give it a descriptive name like "OpenClaw Production". Copy the key immediately.

Step 2 — Configure OpenClaw

llm:
 provider: "openai"
 model: "gpt-4o"
 api_key: "sk-your-openai-key-here"
 max_tokens: 4096
 temperature: 0.7
 streaming: true

Step 3 — Set spending limits

In the OpenAI dashboard under Settings → Limits, set a monthly hard cap and a soft notification threshold:

# Recommended starting limits:
# Hard limit: $50/month
# Soft limit: $30/month (sends email notification)

Step 4 — Configure model routing (optional)

llm:
 provider: "openai"
 default_model: "gpt-4o"
 model_routing:
 complex_reasoning: "gpt-5"
 simple_tasks: "gpt-4o-mini"
 vision_tasks: "gpt-4o"

Step 5 — Start and test

openclaw start

Send a message through your messaging channel and verify the response. Check logs to confirm OpenAI API calls are completing successfully.

Which GPT Model Should You Use?

For most OpenClaw deployments, GPT-4o is the best starting point. It is fast, capable, and cost-effective. GPT-5 is worth the premium for deployments that handle complex analysis, legal work, or multi-step automation chains.

How Do You Fix Common OpenAI API Issues?

• 401 Invalid API key: Check that you copied the full key. OpenAI keys start with sk-. Also ensure the key has not been rotated or deleted in the dashboard.
• 429 Rate limit: You are hitting the tokens-per-minute or requests-per-minute limit. New accounts have lower limits. Apply for a rate limit increase in the OpenAI dashboard or reduce concurrency.
• Billing error (402): Your account has run out of credits or hit the spending cap. Add more credits or increase the hard limit in Settings.
• Function calling not working: Ensure your model supports function calling. GPT-4o and GPT-5 support it natively. Older models like GPT-3.5 have limited function calling support.
• Slow responses: Enable streaming in your config. For faster responses on simple tasks, use GPT-4o Mini instead of GPT-4o.