comparison
Siftfy vs CleanTalk
Updated September 17, 2026
Both are APIs you call server-side, and both stop spam. The difference is what comes back and how you pay for it. CleanTalk answers with an allow/deny verdict drawn from a crowdsourced spam database, priced per website, and also ships a large CMS plugin library on top of the same API. Siftfy returns a calibrated probability and leaves the block, review, and allow thresholds to your application, priced per request.
At a glance
| Feature | Siftfy | CleanTalk |
|---|---|---|
| Output | Calibrated probability (0–1) | check_message/check_newuser return a binary allow (0/1) plus reason codes and a comment; the separate spam_check blacklist lookup returns appears (0/1), spam_rate (0–100%), and a frequency countTwo different methods — allow is the real-time verdict, spam_rate is reputation history. |
| Free tier | 10,000 requests / month, no credit card | 7-day trial at registration, no credit card; no permanent free tier |
| Paid pricing | $9 / mo + $0.0001 / req past 1M | $12/yr for 1 site, $69/yr for 10 sites, $27/mo for unlimited sites — per-site, not per-call |
| Per-minute cap (free) | 60 / minute | Unlimited ("no limits on API calls" per pricing page)The spam_check blacklist method separately documents 100 calls / 60s. |
| Per-minute cap (paid) | 600 / minute, burst-tolerant | Unlimited (per pricing page) |
| Latency | < 10ms p99, CPU only | ~0.1s typical from Europe, per the check_message docs; no percentile published |
| Published evaluation | 89.2% F1 on 1,956 labeled comments (96.6% precision, 82.8% recall) | Not publicly documented as a percentage |
| Language support | Primarily English; non-English degrades | Not specified for the algorithm; documentation localised in English and Russian |
| Self-hostable | No (managed only; dedicated on request) | No — managed cloud only (the crowdsourced blacklist would be moot offline) |
| Stores request bodies | No — metadata only | Yes — submissions feed CleanTalk's crowdsourced spam database that other subscribers query |
| Auth model | Per-key API tokens, revocable in dashboard | Per-account access key (auth_key) |
| Official SDKs | Python (PyPI: siftfy) | First-party libraries for PHP, Python, Django, C# (incl. .NET Core), Ruby, Perl, Laravel and Yii, plus plugins for WordPress, Joomla, Drupal, MODX, Bitrix and other CMSesNode.js is covered by a third-party library linked from the docs; Go by documented request examples. |
CleanTalk figures captured 2026-09-17 from cleantalk.org/price-anti-spam, /help/api-main, /help/api-check-message, /help/api-check-newuser and /help/api-spam-check. If you spot something out of date, email hi@siftfy.io and we'll fix it.
Where CleanTalk genuinely beats Siftfy
The honest tradeoffs:
- Per-site pricing for low-volume sites. $12/year for one website is dramatically cheaper than any paid Siftfy tier if your traffic is small. Siftfy's metered model only wins above the free 10K req/mo line.
- CMS plugin breadth. First-party plugins for WordPress, Joomla, Drupal, MODX, Bitrix, and others mean the install is a checkbox, not a code change. Siftfy has no first-party CMS plugin — you're writing some glue.
- More official client libraries. CleanTalk ships maintained libraries for PHP, Python, Django, C#/.NET, Ruby, Perl, Laravel and Yii against the same
check_message()/check_newuser()API. Siftfy publishes one official SDK (Python) today; every other language calls the REST endpoint directly. - Crowdsourced blacklist. CleanTalk's database is fed by submissions from many subscribed sites, so a known-bad IP that hit another customer is already flagged for you. Useful for IP / email reputation lookups Siftfy doesn't offer.
When Siftfy is the right call
- You want a calibrated probability you can threshold per surface, rather than CleanTalk's binary
allowverdict with reason codes — both are one server-side HTTP call, but only one lets you move the line yourself. - You need separate drop, review, and allow bands driven by one score, instead of tuning a vendor-owned decision.
- You care about p99 latency in the same datacenter as your app — under 10ms — so the spam check doesn't add a perceptible delay to a form submission.
- You don't want submitted content to flow into a third-party crowdsourced database — Siftfy stores metadata only.
10,000 requests / month free, no credit card. Read the API docs or pricing.