Dripmint: White-Label AI Cold Email & Outbound Sales Software (Ruby on Rails Source Code)

Cold email is still one of the most reliable ways to win B2B customers, but running it well takes a stack of tools: a lead list, a sequencer, an AI copywriter, mailbox connections, sending limits and deliverability monitoring. Tools like Instantly, Smartlead, Lemlist and Apollo charge per seat and per mailbox every month, and agencies that run outreach for clients pay those fees many times over.

Dripmint is an AI-native cold email and outbound sales platform that puts all of that in one application. Users import leads, score them into hot, warm and cold tiers, generate multi-step email copy with AI, connect their own mailboxes (SMTP, Gmail or Microsoft 365), and launch drip sequences with reply-aware automation. Step-by-step analytics then show what's working.

It is a finished, deployed Ruby on Rails SaaS, with about 410 commits of development history, staging and production environments, and a CI/CD pipeline. It's ready to rebrand and sell as your own white-label cold email software.

Features

Drip campaigns (sequences)

• Multi-step email sequences with a configurable delay per step (e.g. day 0 kickoff, day 3 follow-up)
• Reply-aware automation: sequences react when a prospect replies
• A campaign list with search, a status filter, progress bars, lead counts and step counts
• A campaign overview with a status and progress summary, a timeline for each step (delay, emails sent, replies, opens) and the latest reply
• A step-by-step performance table: emails sent, replies, bounces and spam reports per step
• Built-in tips for managing drip campaigns

AI copywriting

• Generate Multi-Step Copy writes a full outreach sequence with AI
• AI-assisted campaign content and messaging
• A provider-agnostic AI layer, so AI providers can be swapped without rewriting the core application

Lead management and scoring

• Leads (Pre-Drip) for prospects not yet in a sequence
• Engaged Leads (Drip) for prospects in active campaigns
• Lead scoring with engagement tiers: Hot, Warm and Cold
• Filter leads by tier, bulk-select them and add them to campaigns; the app flags leads already in a campaign
• Name, company, email, tier and score for each lead

Sending accounts and deliverability

• Connect mailboxes to send from your own domain:
  • SMTP, which works with almost any mailbox or host
  • Gmail and Google Workspace through OAuth, for better deliverability
  • Outlook and Microsoft 365 through Microsoft Graph OAuth
• A Sending Overview of today's sent, pending and failed emails across all mailboxes
• Per-mailbox stats: provider, sent, failed, remaining daily quota and the last error
• Scheduled sending handled asynchronously by background jobs
• Delivery-event tracking: opens, replies, bounces and spam reports

Operations

• Schedules for managing send timing
• An Events log of campaign activity
• An Observability page for monitoring the system
• A dashboard, plus an admin panel for platform management
• Authentication with Devise and authorization with Pundit
• Terms, privacy, refund and cookie policy pages

Who it is for

• Lead-generation and outbound agencies that want to own their outreach stack instead of paying per seat, or resell it white-label to clients
• SaaS operators who want to launch a cold email or sales-engagement product in a proven, high-demand category
• Email-marketing and sales-enablement companies adding outbound to their product line
• B2B sales teams and founders who want a private, self-hosted outreach platform
• Niche outreach products, such as recruiting, real estate, link-building or investor outreach, built on the same engine

How it works

1. Create an account and connect one or more sending mailboxes (SMTP, Gmail or Microsoft 365).
2. Import prospects; Dripmint scores them into hot, warm and cold tiers.
3. Create a campaign and build a multi-step sequence, writing it yourself or generating it with AI.
4. Launch. Background jobs send each step on schedule within each mailbox's daily limit.
5. Track opens, replies, bounces and spam reports per step, and optimise the sequence.

Architecture

• A Ruby on Rails monolith with PostgreSQL as the primary database
• Sidekiq + Redis for background processing of scheduled sends and async jobs, so the web app is never blocked
• Hotwire (Turbo + Stimulus) and Bootstrap 5 for the front end
• Devise for authentication and Pundit for authorization
• Data model: accounts, sending identities and integrations, campaigns, sequence steps, contacts, scheduled activities, delivery events and configuration
• Gmail API and Microsoft Graph integrations, plus configurable AI providers
• Separate staging and production environments with a CI/CD deployment workflow

Technology

Ruby on Rails · PostgreSQL · Redis · Sidekiq · Hotwire (Turbo + Stimulus) · Bootstrap 5 · Devise · Pundit · Gmail API · Microsoft Graph · configurable AI providers

What you get

• Full source code (web app and admin panel), with about 410 commits of history
• Database structure and background-job infrastructure
• Integrations and deployment configuration (staging, production and CI/CD)
• 30 days of seller support
• Optional annual maintenance: $1,500/year

Good to know

• Pre-revenue. Dripmint is built and deployed, but it has no paying customers yet. You are acquiring the software asset, not a revenue stream.
• Warm-up is on the roadmap. Mailbox warm-up automation is marked "Soon" in the app.
• Deliverability and compliance. Cold email must follow CAN-SPAM, GDPR and the Google and Microsoft bulk-sender rules (SPF, DKIM, DMARC, unsubscribe). Gmail and Microsoft OAuth apps also need to pass provider verification for public use.
• Branding. Confirm with the seller whether the Dripmint name and domain are included in the sale.