Voxtral Mini Transcribe Playground for Audio Transcription Testing

Transcribe audio with Voxtral Mini, compare accuracy and latency, and export clean text fast.

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 Voxtral Mini Transcribe Playground

Transcribe audio fast

Drop audio, get text—no setup or keys.

Control formatting

Prompt for punctuation, speaker labels, summaries, and structure.

Compare accuracy

Benchmark transcripts across transcription models.

Share & export

Links plus export for docs and workflows.

Private by default

We don’t train on your audio or transcripts.

Instant access

Bring your API keys. Start testing immediately.

Why Us over other LLM Playgrounds

Other playgroundsFrom VC-baked companies

Transcription is hidden behind workflows
Hard to test formatting and cleanup prompts
Setup friction for simple audio tests
Plans priced for enterprise media teams
Support gated by monthly plans tier
VC-backed (optimized for investor returns)

Voxtral Mini Transcribe PlaygroundPowered byLangFast

Quick signup. Bring your API keys.
Transcription-first UX for fast testing
Control formatting with simple prompts
Pay for usage, not bloated monthly plans
Support for creators and 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 Voxtral Mini Transcribe Playground for Audio Transcription Testing transcription playground is a UI to test transcription prompts and run evals on audio-to-text outputs using Voxtral Mini Transcribe Playground for Audio Transcription Testing—focused on accuracy, formatting, and consistency.

Prompt testing and evaluations for transcription: clean text, punctuation, speaker labels, timestamps, summaries, and repeatable checks across the same audio clips.

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

To prevent abuse, apply fair-use limits, and let you save runs, reuse the same audio set for regression tests, and share results.

Word accuracy (at least by spot-checking), punctuation, capitalization, numbers/dates, and how well it handles accents, noise, and overlapping speech.

If the model supports it, yes. Evaluate whether speaker turns are consistent and whether labels drift across the same clip.

Yes. Prompt for timestamps and check whether they are stable and useful (not random or overly frequent).

Yes. Enforce output formats like paragraphs, bullets, “speaker: text” lines, or JSON segments—and measure how often formatting breaks.

Yes. Evaluate summary quality, missed decisions, and whether action items are specific and attributable.

Yes. Reuse a fixed audio set and rerun after prompt changes to see if transcription and post-processing quality improves or regresses.

Yes. Run the same clips side-by-side and compare accuracy, formatting, and speed across providers.

Yes—export to cURL/JS/JSON so your team can reproduce the exact call and parameters.

Yes. Save transcripts, keep prompt versions, and share links for review, editing, or stakeholder approval.

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 transcription evals.

It depends on clip length and model load. We route via a lightweight proxy; compare end-to-end time across models directly.

No. We don’t train on your prompts, audio, or transcripts. 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 transcription workflows. LangFast helps you test prompts and evaluate output formats before you implement pipelines.

Those tools manage datasets, evals, and tracing inside workflows. LangFast is an interactive bench for quick transcription prompt testing and comparisons.

Ship prompts that pass the tests
Don't wait until they break in production
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