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Email Spam Filter

The Email Spam Filter provides real-time spam and phishing protection for applications and services that process inbound emails. It automatically parses, authenticates, and classifies EML-format emails, detecting spam, malicious content, and phishing attempts. ALTCHA Sentinel combines content analysis, natural language processing, and signature verification (ARC, DKIM, SPF) to deliver fast and reliable results — without requiring ongoing training.

This system works quietly in the background, handling high volumes of email while maintaining rapid classification times (~15 ms per 20 KB email). Unlike traditional spam filters that rely on static rules or blacklists, Sentinel is designed to be zero-configuration and low-maintenance, making it ideal for modern SaaS, helpdesk, and web applications.

Features

Intelligent Email Analysis

  • Content & Language Analysis: Inspects email content, structure, and phrasing to detect spammy or malicious patterns.
  • Signature Verification: Confirms sender authenticity using ARC, DKIM, and SPF records.
  • Attachment Handling: Safely extracts attachments and optionally uploads them to S3 or Azure Blob for further inspection.
  • Rapid Classification: Processes typical 20 KB emails in ~15 milliseconds for high-volume services.

Seamless Integration

  • Parse EML to JSON via API: Submit emails through the HTTP API and receive structured content and classification results.
  • Metadata Support: Including sender address and other headers improves detection accuracy.
  • Automatic Risk Assessment: Applies pre-configured rules to decide whether to deliver, flag, or quarantine messages.

Extensible & API-Friendly

  • Similarity Matching (Optional): Submit user-reported spam to improve detection of evolving patterns.
  • Programmatic Access: Integrate email classification into custom workflows, forms, or SaaS platforms.

Alternatives

ALTCHA Sentinel’s Email Spam Filter focuses on automated spam and phishing protection for services that handle user-submitted emails. Similar solutions exist, but Sentinel emphasizes high-speed processing, low maintenance, and out-of-the-box effectiveness:

  • SpamAssassin: Rule-based spam filtering with a long history of email analysis.
  • RSPAMD: Modern open-source spam filtering system.

Integration Steps

Integrating the Email Spam Filter into your service:

  1. Install Sentinel
  2. Follow the Email Spam Filter how-to guide
  3. Submit incoming emails via the EML API for parsing and classification
  4. Optionally, leverage Similarity Matching to continuously improve detection accuracy