Product teams testing prompts get a friendly free plan, but a blog silent since December 2024 raises questions about its future.

Kenning's take

What it does

Langtail lets product teams build, test and deploy the prompts behind their AI features in a spreadsheet-like interface, without needing to code. Teams can compare models and settings, run checks on outputs, and log real usage. An AI Firewall on the Enterprise plan blocks prompt injection and unsafe outputs. Its blog has not posted since December 2024, and the site now also promotes the team's newer product, Macaly.

• Spreadsheet-like prompt editor
• Tests with natural-language evals, pattern matching or code
• Model and parameter experiments
• Logs and performance insights
• AI Firewall against prompt injection and data leaks

Who it suits. Product and engineering teams that ship features built on LLM prompts.

Key facts

Category

Developer tools

Made by

Langtail

How to get it

self-serve sign-up with a free plan; Enterprise through sales

Works on

Web, API

In the UK

Yes

Free plan

Free plan: unlimited users, 2 prompts or assistants, 1,000 logs a month

Pricing

Plan	Price	Billed
Free	$0	month
Pro	$99	month
Team	$499	month
Enterprise	Custom pricing	custom

source

FAQ

Facts from the maker's own pages and the sources listed. Checked 2026-10-11.