free tools · 05 utilities

Anti-spam tools for people who ship forms.

Updated May 12, 2026

Siftfy publishes five free anti-spam tools: a live spam probability tester, an API pricing calculator that compares Siftfy with Akismet, OOPSpam, and CleanTalk, a CAPTCHA friction calculator, a labeled comment-spam dataset, and a contact-form spam checklist. They run in the browser, require no signup, and exist so teams can size the problem before touching any code.

Calculators, checklists, datasets, and a live tester for teams that need fewer junk submissions without making every real visitor solve a puzzle first.

Common questions

Which anti-spam tool should I start with?

If you're scoping a project, start with the anti-spam pricing calculator and the CAPTCHA friction calculator together — they show what a filter will cost and what a CAPTCHA already costs in lost leads. If you have a live form, run the contact-form spam checklist before touching any code.

Are these anti-spam tools free?

Yes. Every calculator, dataset, and checklist on Siftfy's tools page is free, requires no signup, and runs entirely in the browser. The spam probability tester calls the Siftfy API, which has a 10,000-request free tier so the tool stays free for normal use.

Can I use these tools to evaluate other spam-detection APIs?

Yes. The pricing calculator compares Siftfy, Akismet, OOPSpam, and CleanTalk side-by-side. The spam-probability tester is Siftfy-specific, but the dataset of spam examples is provider-agnostic and works against any moderation queue or filter you're testing.

Do you have a CAPTCHA alternative I can test?

Yes. Use the spam probability tester to see how Siftfy scores text without any user-facing puzzle. The CAPTCHA alternatives use case page walks through replacing reCAPTCHA, hCaptcha, or Turnstile with server-side classification.