What is LangFast?
LangFast is a lightweight yet powerful prompt testing platform tailored for product teams, prompt engineers, and developers working extensively with large language models (LLMs). Offering instant, no-signup access to a fully customizable prompt playground, it simplifies the creation and testing of prompt templates using Jinja2 syntax. Users can see real-time raw outputs directly from the LLM without any API abstractions, enabling precise control and immediate feedback. By eliminating manual testing friction, LangFast allows teams to validate prompts, iterate rapidly, and collaborate more effectively on prompt development projects. Created by a team with a proven track record of scaling AI SaaS platforms to over 15 million users, the platform emphasizes control and scalability. LangFast supports seamless sharing of prompt templates, making teamwork intuitive and efficient. Its simple pay-as-you-go pricing model ensures cost predictability and accessibility for teams of all sizes. The platform’s clean and lightweight design means it can be integrated easily into existing workflows without overhead. LangFast empowers teams to accelerate innovation in prompt engineering while managing expenses effectively. This makes it an ideal choice for organizations looking to enhance their AI-driven product development with flexible and transparent prompt testing.
Pricing
Price Starts At:
$60 one time
Free Trial Offered?:
Yes
Integrations
No integrations listed.
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Company Facts
Company Name:
Langfa.st
Date Founded:
2025
Company Location:
United States
Company Website:
langfa.st/new
Product Details
Deployment
SaaS
Product Details
Target Company Sizes
Individual
1-10
11-50
51-200
201-500
501-1000
1001-5000
5001-10000
10001+
Target Organization Types
Mid Size Business
Small Business
Enterprise
Freelance
Nonprofit
Government
Startup
Supported Languages
English