Developer tools you buy once and keep.

Private GitHub repositories you're invited to, with every update, under a commercial license.

Browse the tools See falsify work

Browse by category

Web & documents Read, edit and reuse the web and PDFs. 6 tools Testing & code health Find what your tests and code hide. 7 tools AI quality & safety Check and control what your AI does. 6 tools AI cost & reliability Cap AI spend and survive vendor outages. 3 tools Email & messaging Receive, untangle and safely send messages. 8 tools Backends & data Move and run app data without rewrites. 3 tools Security & hardening Harden what strangers reach first. 3 tools

Find pytest tests that pass for the wrong reason.

falsify 1.0.2real run

$ falsify check
app/orders.py:12:9: [success-from-except] returns success (`{'ok': True}`) from inside an `except` block, so the caller cannot tell this failure from a real success
    fix: return the failure (ok: False, an error status, or re-raise). If success is right here, name why in the payload (e.g. a `skipped` key) or add `# falsify: ok <why>`.

Real output: falsify 1.0.2, its first 3 lines. The whole run is on falsify's page.

Buy falsify for $49 About falsify

How buying works

Pick a tool. Watch it run on its page first.
Pay once. One payment per tool, plus sales tax where it applies.
Accept the GitHub invite. Every update lands in the same repository.