Ever wasted hours debugging why your LLM app isn't working — only to find your API key was invalid? LLM Key Tester solves this in seconds. Paste any key from OpenAI, Anthropic, Google, Mistral, Groq & more — instantly know: ✅ Is the key valid? ✅ Which models it has access to? ✅ How keys compare model-wise? 🔒 Key is NEVER stored or logged — ever. 🆓 No signup. No credit card. Lifetime free. ⚡ Results in under 3 seconds. Built for devs tired of guessing.

Framer — Launch websites with enterprise needs at startup speeds.

Launch websites with enterprise needs at startup speeds.

Hey Product Hunt! 👋

I built LLM Key Tester after one too many hours lost to a stupid root cause — an invalid API key.

You know the drill:

→ Your LLM app isn't working

→ You check your code, your prompts, your logic

→ 45 minutes later... it was just a bad key 🤦

So I built the tool I wish existed.

🔍 What it does:

• Validates keys from OpenAI, Anthropic, Google, Mistral, Groq & more

• Shows exactly which models each key has access to

• Lets you compare multiple keys side by side

• Returns results in under 3 seconds

🔒 What it never does:

• Never stores your key

• Never logs it

• Never sends it anywhere except the provider's own API

💡 Who it's for:

→ Devs switching between API keys across projects

→ Teams sharing keys who need to audit access

→ Anyone who's ever typed "why isn't this working" into Google at 2am

It's 100% free. No account. No credit card. Just paste and go.

Would love your feedback — what providers or features should I add next? Drop a comment below! 🙏

As someone who builds side projects with 4-5 different LLM providers, I'm constantly juggling API keys and hitting random auth errors.

This is exactly the kind of micro-tool that looks simple but saves massive headaches.

No login. No email. Just paste your key → instant answer. That's how dev tools should work.

Gave it an upvote — hope this gets the attention it deserves! 👆 If you work with AI APIs at all, spend 10 seconds trying this.