LangFast

LangFast

Langfa.st
+
+

Related Products

  • Google AI Studio
    9 Ratings
    Visit Website
  • Vertex AI
    726 Ratings
    Visit Website
  • AI Video Cut
    1 Rating
    Visit Website
  • Boozang
    15 Ratings
    Visit Website
  • Hostinger Horizons
    64 Ratings
    Visit Website
  • Blackbird API Development
    1 Rating
    Visit Website
  • UserTesting
    2,201 Ratings
    Visit Website
  • qTest
    Visit Website
  • Aikido Security
    100 Ratings
    Visit Website
  • SenseIP
    1 Rating
    Visit Website

About

LangFast is a lightweight prompt testing platform designed for product teams, prompt engineers, and developers working with LLMs. It offers instant access to a customizable prompt playground—no signup required. Users can build, test, and share prompt templates using Jinja2 syntax with real-time raw outputs directly from the LLM, without any API abstractions. LangFast eliminates the friction of manual testing by letting teams validate prompts, iterate faster, and collaborate more effectively. Built by a team with experience scaling AI SaaS to 15M+ users, LangFast gives you full control over the prompt development process—while keeping costs predictable through a simple pay-as-you-go model.

About

Prototype and productionize generative AI apps, built for engineers, not just ML practitioners. No more switching between platforms or wrestling with different APIs, focus on creating, not configuring. Use a familiar interface to prompt engineer and work with AI. Use parameters to easily streamline your workbooks into reusable templates. Create workflows by chaining model outputs from LLMs, image, and audio models. Create organizations to manage workbooks amongst your teammates. Share your workbook to the public or specific organizations you define with your team. Comment on workbooks and easily review and compare workbooks with your team. Develop templates for yourself, your team, or the broader developer community, get started quickly with templates to see what people are building.

Platforms Supported

Windows
Mac
Linux
Cloud
On-Premises
iPhone
iPad
Android
Chromebook

Platforms Supported

Windows
Mac
Linux
Cloud
On-Premises
iPhone
iPad
Android
Chromebook

Audience

Product teams, software engineers, prompt engineers, AI developers, ML researchers, startup founders, and technical writers working on AI-powered features or language model integrations.

Audience

Engineering teams in need of an AI developer platform that helps build AI-powered apps

Support

Phone Support
24/7 Live Support
Online

Support

Phone Support
24/7 Live Support
Online

API

Offers API

API

Offers API

Screenshots and Videos

No images available

Screenshots and Videos

Pricing

$60 one time
Free Version
Free Trial

Pricing

$50 per month
Free Version
Free Trial

Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

This software hasn't been reviewed yet. Be the first to provide a review:

Review this Software

Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

This software hasn't been reviewed yet. Be the first to provide a review:

Review this Software

Training

Documentation
Webinars
Live Online
In Person

Training

Documentation
Webinars
Live Online
In Person

Company Information

Langfa.st
Founded: 2025
United States
langfa.st/new

Company Information

LastMile AI
lastmileai.dev/

Alternatives

Alternatives

Vellum AI

Vellum AI

Vellum
Vellum AI

Vellum AI

Vellum

Categories

Categories

Integrations

GPT-3.5
GPT-4
Hugging Face
IBM watsonx.data
OpenAI
PaLM 2
Stable Diffusion
Whisper

Integrations

GPT-3.5
GPT-4
Hugging Face
IBM watsonx.data
OpenAI
PaLM 2
Stable Diffusion
Whisper
Claim LangFast and update features and information
Claim LangFast and update features and information
Claim LastMile AI and update features and information
Claim LastMile AI and update features and information