Codestral Embed Playground for Code embeddings

Generate embeddings with Codestral Embed, test retrieval quality, and compare similarity results across embedding models.

Test your first prompt now

Bring your API keys. Pay once, use forever.

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800+ users already test and evaluate prompts with LangFast

Best Codestral Embed Playground

Test RAG embeddings

Create vectors, compare similarity behavior, and tune chunking.

Compare retrieval quality

Evaluate embeddings across models on your dataset.

Use repeatable inputs

Templates and variables for consistent testing.

Export results

Make it easy to integrate into your pipeline.

Private by default

We don’t train on your data.

Instant access

Bring your API keys. Start testing immediately.

Why Us over other LLM Playgrounds

Other playgroundsFrom VC-baked companies

Embedding tests buried behind platforms
No simple way to compare retrieval quality
Too much setup for quick experiments
Pricing bundled with expensive “AI suites”
Support favors enterprise customers
VC-backed (optimized for investor returns)

Codestral Embed PlaygroundPowered byLangFast

Quick signup. Bring your API keys.
Test embeddings for search/RAG quickly
Compare similarity behavior across runs
Pay for usage, not giant monthly plans
Support for builders and small teams
Bootstrapped (optimized for customer UX)

Explore All Features

  • Supported AI Models

  • GPT-5
  • GPT-5 Mini
  • GPT-5 Nano
  • GPT-5 Nano
  • GPT-4.5 Preview
  • GPT-4.1
  • GPT-4.1 Mini
  • GPT-4.1 Nano
  • GPT-4o
  • GPT-4o Mini
  • O1
  • O1 Mini
  • O3
  • O3 Mini
  • O4 Mini
  • GPT-4 Turbo
  • GPT-4
  • GPT-3.5 Turbo
  • Claude AI Models (soon)
  • Gemini AI Models (soon)
  • Model Fine-tuning (soon)
  • Model configuration

  • Custom System Instructions
  • Reasoning Effort Control
  • Stream Response Control
  • Temperature Control
  • Presence & Frequency Penalty
  • User Interface

  • Customizable Workspace
  • Wide Screen Support
  • Hotkey & Shortcuts
  • Voice Input (soon)
  • Text-to-Speech (soon)
  • Playground Experience

  • Prompt Library
  • Prompt Templates & Variables
  • Jinja2 Templates Support
  • Upload Documents (soon)
  • Language Output Control
  • Parallel Chat Support
  • Prompt Management

  • Prompt Folders
  • Edit & Fork Prompts
  • Prompt Versioning
  • Upload Documents (soon)
  • Share Prompts
  • Cost & Performance

  • Cost estimation
  • Token usage tracking
  • Context length indicator
  • Max token settings
  • Security and Privacy

  • Private by Default
  • API Tokens Cost Estimation
  • No chats used for training

    Integrations

  • Web Search & Live Data (soon)
  • Plugins

  • Custom Plugins (soon)
  • Image search plugin (soon)
  • Dall-E 3 (soon)
  • Web page reader (soon)
Wall of love

Meet LangFast users

LangFast empowers hundreds of people to test and iterate on their prompts faster.

@Rubik_design
Rubik@Rubik_design
Happy that @eugenegusarov built @langfast. This is the best LLM Playground and I tested so many!So much better than other playgrounds. Everything is right at hand when you need itLangfast PlaygroundAug 24, 2025
@codezera11
CodeZera@codezera11
That's exactly the kind of tool AI devs need in production. Prompt testing is the new debugging, and it eats up real time.Jul 17, 2025
Adrian
Adrian@shephardica
I've felt this pain in my day job - testing and validating prompts is currently difficult, error prone, and just not polished. Great problem to solve 👍Jul 13, 2025
Sasha Reminnyi
Sasha Reminnyi 🇺🇦Founder at Growth Kitchen
Great, had similar idea since launch of GPT, thanks for making that alive 🙏Aug 3, 2025
Glib Ziuzin
Glib ZiuzinFounder BUD TUT
Excited for this 🔥Jul 14, 2025
Rajiv Dev
R𝗮𝗷𝗶𝘃.𝗱𝗲𝘃Jul 17, 2025
I saw your app yeah that was usefullJul 17, 2025

Frequently Asked Questions

A Codestral Embed Playground for Code embeddings embeddings playground is a UI to test embeddings for search/RAG—generate vectors, run similarity checks, and do quick eval-style retrieval tests without building an indexing pipeline.

Prompt testing and evaluations for retrieval: “does this embed model group the right things together?” and “does it retrieve the right items for my queries?”

Yes. Bring your API keys. LangFast routes requests through our proxy.

To prevent abuse, apply fair-use limits, and let you save test sets, reuse comparisons, and share results with your team.

Nearest-neighbor relevance, semantic clustering, and whether similarity scores separate “correct” vs “distractor” documents for your real queries.

Create a small gold set: queries + expected relevant docs. Embed them, run similarity ranking, and check if the right docs land in the top results.

Yes. Run the same gold set and compare hit rate, ranking quality, and cost/latency.

Typically cosine similarity is the baseline for embedding comparisons. If you need a specific metric, use the exported call and compute it in your stack.

Yes. Embeddings often fail because chunking is wrong. Compare retrieval quality across different chunk sizes and overlaps using the same gold set.

Yes. Use cross-language query/doc pairs and evaluate whether the model retrieves correctly across languages.

Yes—export to cURL/JS/JSON so engineering can reproduce embedding calls and plug them into your indexing workflow.

LangFast is free to use with some basic features. You need to provide your own API keys to run models and use the app. When you add your API keys, you pay the model provider (e.g., OpenAI) for the credits/tokens you use. LangFast premium features can be unlocked with a one-time purchase.

Wait for reset or add paid usage to continue running embedding evaluations.

No. We don’t train on your prompts or data. Sharing is opt-in and retention is configurable.

Requests route to model providers. See the Data & Privacy page for processing regions and details.

LangChain helps you build RAG systems. LangFast helps you choose the embedding model and validate retrieval behavior before you implement.

Those tools manage datasets, evals, and tracing in workflows. LangFast is a quick bench for interactive embedding tests and model comparisons.

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