Our take
Pick Langtail if you're on a product team who will stay on Free at $0 (2 prompts, 1,000 logs, 30-day retention, unlimited users) while they open a first Playground, then Pro at $99/month + VAT when they need 20 prompts and unlimited logs. Pick Promptfoo if you're on a app team who will run Community for $0 (MIT, self-host) and only buy Enterprise when they need SSO, a shared dashboard, and more than 10k probes.
Best for
Langtail A spreadsheet-style prompt you ship at a public $
Promptfoo Fail the build before a prompt ships
Free plan
Langtail $0 · /month + VAT. Unlimited users. 2 prompts or assistants. 1,000 logs / month. 30-day retention. Public shareable apps
Promptfoo No free plan
Lowest paid
Langtail Pro $99/mo
Promptfoo Not published by the vendor
Coding agent
Langtail
Promptfoo Eval matrix
Runs where
Langtail Local or hosted
Promptfoo Hosted
Watch out
Langtail Free is 2 prompts
Promptfoo Community red team is 10k probes/month
Last checked
Langtail 2026-10-27 · langtail.com/pricing
Promptfoo 2026-10-27 · promptfoo.dev/pricing
product teams who will stay on Free at $0 (2 prompts, 1,000 logs, 30-day retention, unlimited users) while they open a first Playground, then Pro at $99/month + VAT when they need 20 prompts and unlimited logs.
Read the Langtail pageapp teams who will run Community for $0 (MIT, self-host) and only buy Enterprise when they need SSO, a shared dashboard, and more than 10k probes.
Read the Promptfoo page
