Kuju Email
A complete, modern email platform with IMAP, webmail, calendar, contacts, AI-powered productivity and security, and full administrative control. Fully managed so you can focus on your business.
What Sets Kuju Email Apart
Kuju Email isn’t another email wrapper. It’s a ground-up email platform designed for organizations that need productivity, security, and modern features.
AI That Actually Helps You Work
One-click AI replies, tone-controlled rewrites, task extraction, attachment summarization, natural language search and commands, waiting-on-reply tracking with nudge, contact intelligence, and an inbox summary dashboard. AI is woven into every workflow.
Complete Platform, One Service
IMAP, webmail, REST API, CalDAV/CardDAV, workspaces, activity feed, vacation responder, AI productivity tools, and delivery handling — all fully integrated. No bolting together separate services.
AI Security Built In, Not Bolted On
Two-tier threat detection, Google Safe Browsing URL checks, message intelligence panels, tracking pixel detection, virus attachment stripping, and sender verification are native — not third-party add-ons.
Knows Your Documents Too
Extract and AI-summarize PDF, DOCX, XLSX, CSV, and more — directly from email attachments. Extracted text is indexed so you can search inside attachments, not just email bodies.
True Multi-Tenant Isolation
Per-domain admin delegation, API key isolation, partitioned storage, branded hostnames with automatic TLS, message retention policies, and separate spam thresholds. Tenants are fully isolated.
Self-Hosted Option Coming Soon
Love the platform but need to run it on your own infrastructure? A self-hosted deployment option is on the roadmap for organizations with strict compliance or data residency requirements.
Complete Feature Set
Everything you need to run a production email platform.
Email Access
Full IMAP Server
RFC 3501 compliant with server-side SORT, THREAD, and full-text SEARCH. Works with Thunderbird, Apple Mail, Outlook, K-9 Mail, and any standard client. Push notifications via IMAP IDLE.
Modern Webmail
Full-featured browser-based client with compose, reply, forward, drag-and-drop attachments and message movement, folder management, auto-save drafts, forward-as-attachment (.eml), and browser push notifications.
Command Palette & Natural Language Commands
Press Cmd+K for 17+ fuzzy-searchable commands. Also supports natural language commands — type "move this to archive" or "flag for follow-up" and the AI interprets and executes the action.
Thread Views
Three selectable conversation designs: Command-Centric (summary + actions), Document-Centric (structured AI sections with key points, decisions, and action items), or Timeline + Context Stream.
Workspaces
Organize email by project with tag-based grouping. Messages can belong to multiple workspaces while staying in their original folders. Set auto-assign rules by sender domain, participant, or subject keyword.
Vacation Responder
Smart auto-reply with AI calendar detection. Set a custom subject and message, configure date ranges, and let the system automatically detect vacation events. Deduplicates replies per sender and skips mailing lists, spam, and BCC messages.
AI Productivity
AI Reply
Generate contextual reply drafts with one click. The AI reads the conversation and drafts a relevant response — review, edit, and send.
AI Rewrite & Compose
Rewrite messages with tone control — Professional, Friendly, Concise, or Formal. Full version history (v1, v2, v3...) with instant restore. Quoted text is preserved automatically.
Natural Language Search
Search your inbox the way you think. Type queries like "invoices from last month" or "unread emails with attachments" and the AI interprets them into precise searches with timezone-aware date resolution.
AI Task Extraction
Automatically extract action items, deadlines, and follow-ups from emails. Tasks appear in a dedicated sidebar view with pending/completed filters and one-click "Add to Calendar" for detected dates. Inline date detection highlights dates right in email bodies.
Attachment Knowledge Extraction
Extract text from and AI-summarize document attachments. Supports PDF, DOCX, XLSX, CSV, plain text, HTML, Markdown, JSON, and XML (up to 10 MB). Extracted text is indexed for search so you can find content inside attachments.
Waiting-On-Reply Tracker
Automatically detects sent messages expecting a reply. Tracks aging with green/yellow/red indicators, auto-matches incoming replies, and offers a "Nudge" button to generate follow-up drafts.
Inbox Summary Dashboard
At-a-glance inbox health: mail volume, security counts, productivity metrics, AI classification breakdown, top 10 senders with display names, response rate, and recent quarantine list.
Calendar & Contacts
Native CalDAV Calendar
Full RFC 4791 support with month/week/day views, multi-calendar with color coding, all-day events, and sync with Apple Calendar, Thunderbird, and any CalDAV client. AI-powered one-click "Add to Calendar" from detected dates in emails.
Native CardDAV Contacts
RFC 6352 contact management with multi-value email and phone fields (with type labels), address fields, organization and job title, notes, multiple address books, and full-text search across all fields.
Contact Intelligence & People View
AI-powered communication pattern analysis. See your top contacts ranked by frequency, identify dormant contacts, view per-contact stats (emails sent/received, last contact), and quick-add people to your address book from the People view.
Activity Feed
A unified chronological stream combining messages, calendar events, and tasks in one view. Filter by type to focus on what matters. Available as a dedicated view in the sidebar.
AI-Powered Security
Message Intelligence Panel
Tabbed security analysis with AI Insights and Security views: SPF/DKIM/DMARC verification, sender identity checks, relay hop tracing, URL inspection, ClamAV antivirus scanning, and AI threat assessment with evidence-based reasoning.
Google Safe Browsing
Real-time URL threat checking against Google Safe Browsing API. Every link in an email is verified against malware, social engineering, unwanted software, and harmful app databases with threat level badges and cached results.
Two-Tier Spam & Phishing Detection
Tier 1 heuristics run on every message with zero API dependency. Tier 2 LLM analysis provides deep content evaluation. User reclassifications automatically train the RSPAMD filter for continuous improvement.
Smart Inbox (AI Categorization)
Automatic intent classification — personal, newsletter, transactional, notification, calendar, task, financial, social — powered by a cost-optimized tiered AI model architecture (fast/standard/premium).
Tracking Protection
Detects tracking pixels from services like Mailchimp, ConvertKit, and GitHub. Toggle to strip trackers from displayed messages with sender domain identification so you control what gets tracked.
Virus Attachment Stripping
When ClamAV detects an infected attachment, it's automatically stripped from the message while preserving the email body — so you receive the message safely without the malicious file.
Security & Authentication
Automatic DKIM Rotation
Zero-downtime DKIM key rotation with three-phase lifecycle: generate, switch, cleanup. DNS propagation verification, configurable intervals (default 30 days), and support for PowerDNS and Cloudflare with auto-detection.
Modern Auth Methods
TOTP two-factor authentication (Google Authenticator compatible), WebAuthn/FIDO2 passkeys for passwordless login, automatic JWT key rotation on configurable schedule, and CSRF protection with double-submit cookies.
Encrypted Secrets Storage
AES-256-GCM encryption with Argon2id key derivation. Supports internal store, HashiCorp Vault/OpenBao, AWS Secrets Manager, GCP Secret Manager, and Azure Key Vault.
Administration & Operations
Multi-Domain Multi-Tenant
Full multi-domain support with per-domain configuration, admin delegation, account quotas, domain-partitioned storage, and per-domain API key isolation. Tenants are fully isolated.
Per-Domain Branding
Custom logos, favicons, themes, CSS, and branded webmail URLs (webmail.yourdomain.com). Full dark mode with OS preference detection and user-level theme overrides.
Message Retention Policies
Configure automatic message deletion by age at the domain level with per-folder and per-account overrides. Background cleanup worker handles batch deletion with storage reclamation on a configurable schedule.
Delivery Pipeline Controls
Configurable spam score thresholds per domain — set junk routing and hard drop thresholds separately. Quarantine auto-expiry with configurable retention. Drop statistics API for monitoring.
Analytics Dashboard
Delivery volume charts, status breakdown, spam score distribution, scan verdict breakdown, top senders and source IPs, and plugin token usage tracking with cost estimation. Time range selectors for 24h/7d/30d views.
Prometheus Monitoring
Standard /metrics endpoint with application metrics (domains, accounts, messages, storage), compression stats, and Go runtime metrics. Grafana compatible.
Extensibility
Plugin System
gRPC subprocess architecture for plugins. Install and uninstall dynamically without restart. Built-in plugins for ClamAV antivirus, AI spam scanning, AI inbox categorization, webhook forwarding, and RSPAMD spam training.
Full REST API
JWT-authenticated API for folders, messages, drafts, calendar, contacts, analysis, tasks, feed, workspaces, vacation, retention, and admin operations. Over 80 endpoints with OpenAPI specification.
Plus Addressing
Create unlimited aliases on-the-fly with user+tag@domain. Messages are stored with the tag for easy filtering and organization. Catch-all delivery available per domain.
Ready to get started?
Choose the plan that fits your organization. Start with the free Community tier and upgrade as you grow.