Langfa.st vs. ZenCall
Langfa.st
Langfa.st is a fast and minimal playground for testing and refining AI prompts. It supports over 50 large language models, including OpenAI, Anthropic, Mistral, Cohere, Google, and others — all available instantly without setup. You can insert variables, use Jinja2 templating, and compare outputs across models. There’s no need to sign up or bring your own API keys — it works out of the box. Langfa.st was built to eliminate the friction of existing tools: complicated UIs, required credentials, or overpriced subscriptions. It gives AI teams and prompt engineers a clean, disposable space to experiment, debug, and iterate — all in one tab. Free to use. You only pay if you need more volume or power features.
ZenCall
AI phone agent to receive and make phone calls for you
Reviews
Reviews
| Item | Votes | Upvote |
|---|---|---|
| Works without login or API key | 1 | |
| Supports 50+ models out of the box | 1 | |
| Built-in support for variables and Jinja2 templating | 1 | |
| Instant response, no setup required | 1 | |
| Clean and distraction-free UI | 1 |
| Item | Votes | Upvote |
|---|---|---|
| No custom API key support (yet) | 1 | |
| Not ideal for running complex multi-turn chats | 1 |
| Item | Votes | Upvote |
|---|---|---|
| Efficient and robust | 1 | |
| Great customer service | 1 |
| Item | Votes | Upvote |
|---|---|---|
| No cons yet, would you like to add one? | ||
Frequently Asked Questions
Langfa.st is designed specifically for testing and refining AI prompts with support for over 50 large language models, making it ideal for AI teams and prompt engineers. It offers a clean UI and instant responses without the need for login or API keys. In contrast, ZenCall functions as an AI phone agent, focusing on making and receiving phone calls. If your primary need is prompt engineering and model testing, Langfa.st would be the better choice, while ZenCall excels in automating phone communications.
Yes, ZenCall can handle tasks related to phone communications, such as making and receiving calls, which Langfa.st cannot do as it is focused on AI prompt testing. ZenCall is efficient in managing phone interactions, while Langfa.st is tailored for AI model experimentation. Therefore, if your needs involve telephony, ZenCall is the appropriate tool.
Langfa.st offers a clean and distraction-free UI that allows users to experiment with AI prompts without any setup, making it very user-friendly for those focused on AI development. ZenCall, while efficient and robust, is primarily focused on phone interactions and may not have the same level of simplicity for users looking to test AI models. Therefore, for ease of use in AI prompt testing, Langfa.st is likely the more user-friendly option.
Langfa.st is a fast and minimal playground for testing and refining AI prompts. It supports over 50 large language models, including OpenAI, Anthropic, Mistral, Cohere, Google, and others — all available instantly without setup. Users can insert variables, use Jinja2 templating, and compare outputs across models without needing to sign up or provide API keys.
Pros of Langfa.st include: it works without login or API key, supports over 50 models out of the box, has built-in support for variables and Jinja2 templating, provides instant responses with no setup required, and features a clean and distraction-free user interface.
Cons of Langfa.st include the lack of custom API key support at this time and it may not be ideal for running complex multi-turn chats.
Langfa.st is particularly beneficial for AI teams and prompt engineers who need a clean, disposable space to experiment, debug, and iterate on AI prompts without the friction of complicated UIs or required credentials.
Yes, Langfa.st is free to use. Users only pay if they need more volume or access to power features.
ZenCall is an AI phone agent designed to receive and make phone calls on your behalf. It utilizes advanced artificial intelligence to handle various call-related tasks efficiently.
Pros of ZenCall include its efficiency and robustness, as well as great customer service. There are currently no listed cons for ZenCall.
