Stop spam before it
reaches your database.
KireiFilter is a server-side API that scores incoming content — comments, contact form submissions, registrations, email — and tells you whether it's spam. No CAPTCHA. No friction for real users.
spam score
How it works
One API call. A confidence score back.
Send the content, IP address, and optional metadata to POST /api/v1/spam-check. KireiFilter runs it through multiple detection layers and returns a score between 0.0 and 1.0, a verdict, and which signals fired. You decide what to do with the result.
curl -X POST \
https://kireifilter.net/api/v1/spam-check \
-H "Authorization: Bearer <api-key>" \
-d '{
"content": "Buy cheap meds at...",
"ipAddress": "203.0.113.42",
"email": "user@example.com",
"type": "comment"
}'{
"verdict": "spam",
"score": 0.87,
"signals": [
{ "layer": "heuristic", "score": 0.72 },
{ "layer": "rbl", "score": 0.15 }
],
"checked_at": "2025-03-18T09:14:22Z"
}Create an account
Sign up, grab your API key from the dashboard. No credit card required to start.
Send content to the API
One HTTP call before you persist user-submitted data. Works with any language or framework.
Act on the score
Reject, flag for review, or approve — your code, your rules. We just provide the signal.
Features
Everything you need to fight spam.
IP & Domain Denylist
Known bad IPs and domains are hard-blocked immediately. Add your own blocklist entries per account.
Heuristic Analysis
Pattern-based scoring detects keyword density, link counts, excessive caps, suspicious phrases, and more.
RBL Checks
Real-time blocklist lookups to identify IPs with a history of sending spam or abusive traffic.
Entropy Scoring
Measures character-level randomness to catch machine-generated gibberish and auto-spun content.
Content Fingerprinting
Identifies repeated spam campaigns by hashing content. The same template sent by different bots gets caught the second time.
Email Alias Abuse Detection
Detects disposable addresses, normalized duplicates, and patterns that signal throwaway accounts.
Use cases
Works anywhere users submit content.
Blog comments & reviews
Score every submission before it hits your database. Auto-approve clean content, hold grey-area posts, reject obvious spam.
Contact forms
Block bot floods without CAPTCHA. Legitimate users see nothing different — spam never reaches your inbox.
User registrations
Catch fake signups, disposable emails, and bot accounts at the point of registration.
Inbound email pipelines
Classify raw email content, headers, and sender data before processing. Useful for support inboxes and ticketing systems.
Detection pipeline
Layered, not a black box.
Each request passes through independent detection layers. Scores are accumulated, high-confidence matches short-circuit the chain. You get the final score and every signal that fired.
Principles
Built with a few hard rules.
No CAPTCHA, ever
Spam filtering happens on your server. Real users never solve a puzzle, click a checkbox, or prove they're human.
EU-hosted & GDPR-compliant
Data stays in Europe. No third-party trackers, no cross-account data sharing, no surprises at audit time.
You own the decision
We return a score and signals. What you do — reject, queue, approve — stays in your code. No magic auto-blocking outside your control.
Pricing
Simple, usage-based pricing.
Start for free. Scale when you need to.
Free
- 100 req / month
- 1 API token
- All detection layers
-
No request historyNo verdict correctionsCommunity support
Starter
€100 billed yearly
- 500 req / month
- 2 API tokens
- Commercial use
- 24h request history
-
No verdict correctionsNo custom denylistEmail support
Pro
€160 billed yearly
- 1,000 req / month
- 5 API tokens
- Correct misclassifications
- 7-day history
-
Analytics dashboardCustom denylist (25 rules)Priority email support
Max
€360 billed yearly
- 10,000 req / month
- Unlimited tokens
- Denylist + allowlist rules
- Priority support
-
30-day historyAnalytics dashboardVerdict correctionsCustom allowlist (100 rules each)
Ready to cut out spam?
Free plan available. No CAPTCHA, no friction, no fuss.