Cat Mouse Mailport
Self-service email marketing, self-hosted
About Cat Mouse Mailport
A multi-tenant email marketing platform with campaign builder, subscriber management, CSV import, and Stripe billing. Features a Monaco code editor for email templates, Upstash Redis rate limiting, and PostHog analytics.
The Challenge
Small businesses need email marketing but Mailchimp-style platforms are expensive and opinionated. Self-hosted alternatives are either too technical to set up or lack essential features like template editing, subscriber management, and deliverability monitoring.
Our Solution
We built a full-featured email marketing platform with a Monaco-powered template editor for HTML emails, CSV import for subscriber lists, and Stripe billing for SaaS distribution. Upstash Redis handles rate limiting to protect deliverability, and Supabase RLS provides multi-tenant isolation.
The Results
The platform supports the full campaign workflow (list management, template creation, scheduling, sending, and analytics) inside a multi-tenant architecture where each tenant adds negligible overhead. PostHog tracks engagement metrics alongside Mailgun delivery stats.
Key Features
Monaco Template Editor
Full-featured HTML email editor powered by Monaco (the VS Code editor engine) with syntax highlighting and preview.
Subscriber Management
Import subscribers via CSV, manage segments, handle unsubscribes, and track engagement per contact.
Campaign Scheduling
Schedule campaigns for future delivery with Vercel Cron jobs and Upstash Redis rate limiting.
Multi-Tenant Billing
Each organization gets isolated data via RLS with Stripe-managed subscription tiers.