Ship AI Apps With
Fewer Surprises

Debug prompts, run tests, and observe what’s happening in production.
Speed up your AI development workflow with Langtail.

Langtail Introductory Video
GoodlokDeepnoteMangowebWopeMockuuups Studio


Debug prompts

Iterate at Lightning Speed
Fine-tune prompts and settings to optimize your LLM's performance in record time.
Use advanced features
Support for variables, tools (functions), vision and more built right in.
Instant Feedback Loop
See how prompt changes affect your AI's output instantly.
Version History
Roll back to previous prompt versions with full version history.


Run tests

Prevent surprises
Modify your prompts and rely on your test suite to ensure that you aren't breaking your app, rather than using manual testing.
Benchmark prompt variations
Run tests on different prompt versions to identify the top-performing one.
Upgrade models with confidence
Ensure your app's stability when moving to new model versions by leveraging your test suite.


Deploy prompts

Iterate faster
Publish your prompts as API endpoints, allowing you to make changes without redeploying your entire application.
Fit your development workflow
Deploy prompts to separate preview, staging, and production environments to keep everything aligned with the way your team ships.
Decouple prompts from code
Separate prompt development from app development, enabling your team to work more independently and efficiently.


Monitor Production

Detailed API Logging
Capture performance data, token count, and LLM costs for every API call to the LLM.
Metrics Dashboard
View aggregated prompt performance metrics including request count, cost, and latency.
Problem Detection
Identify issues by monitoring user interactions with your app in production.

Engineering and AI teams Langtail

“Langtail simplifies the development and testing of Deepnote AI, enabling our team to focus on further integrating AI features into our product”

Ondřej Romancov

“This is already a killer tool for many use-cases we are already using it for. Super excited for the upcoming features and good luck with the launch and further development! 💜”

Jakub Žitný

“Been using LangTail for a few months now, highly recommend. It has kept me sane. If you want your LLM apps to behave uncontrollably all the time, don't use LangTail. On the other hand, if you are serious about the product you are building, you know what to do :P Love the product and the team's hard work. Keep up the great work!”

Sudhanshu Gautam

“I have used Langtail for prompt refinement, and it was a real timesaver for me. Debugging and refining prompts is sometimes a tedious task, and Langtail makes it so much easier. Good work!”

Martin Staněk

“LLM products are creating a flurry of bad experiences in their rush to hit the market quickly. But Petr and his team have been demonstrating since day one just how serious they are about doing this job with outstanding designs. I've been following them for over a year now and I highly recommend them to everyone. I'm certain they're going to reach fantastic places.”

Yiğit Konur

“Been using Langtail for a while, and it has made working with our clients a breeze”

Soham Adwani

“Unpredictable behavior of LLMs, team collaboration on prompts and robust evaluation were the biggest pains for me when I was building my app. But now it's solved thanks to LangTail. It's a great product.”

Michal Stoklasa
No-code Playground
Write and run prompts without coding, perfect for non-technical users.
Adjustable Parameters
Fine-tune LLM behavior by adjusting temperature, top_p, and other settings.
Test Suites
Prevent surprises by running tests on your prompts.
Benchmark Variations
Identify top-performing prompt variations through benchmarking.
Seamless Deployment
Deploy prompts as API endpoints across environments.
Detailed Logging
Capture performance data, token count, and LLM costs for every API call.
Metrics Dashboard
View aggregated prompt performance metrics, including request count, cost, and latency.
Problem Detection
Identify issues by monitoring user interactions with your app in production.
Collaborative Workflow
Share prompts and work together with your team seamlessly.

Ready to upgrade your AI dev workflow?

Langtail is the most enjoyable way to debug, test, and observe LLM-powered apps. Try it for free, no credit card needed.