Mailnib
Multi-Tenant Drag & Drop Email Builder SaaS with AI
From $99one-time · full source code · 12 months of updates
Founding-customer pricing — first 20 licences
Watch the Walkthrough
Product Overview
Mailnib is a self-hosted, multi-tenant email builder you run as your own SaaS. Your customers sign up, pick a plan and design emails that look right in every inbox. You set the prices, take the payments and keep the revenue.
The Market Gap
Email builders are either rented SaaS you can never own or bare editors with no business around them. Anyone who wants to sell email design as a product has to build tenancy, billing, branding and inbox-safe rendering from scratch.
Systems Strategy
Shipped a complete email builder business in one Node process and one PostgreSQL database: a 25-block editor that works on phones, 79 templates, an AI assistant, six export formats, one-click publishing, five payment gateways and row-level tenant isolation, backed by more than 3,000 automated tests.
Live Sandbox Demo Credentials
Test the live sandbox environment of the platform. Use the credentials below at the demo login portal.The sign-in pages have one-click buttons for both accounts. Exports, AI, payments and account changes are switched off in the demo; everything else is live.
operator@demo.example.comexplore-the-consolecustomer@demo.example.comexplore-the-builderYour own email builder business, ready to launch
Mailnib designs and exports email. It never sends campaigns, so you never deal with mailing lists, sending reputation or deliverability. Your customers export clean HTML or publish straight into the Mailchimp, Brevo, SendGrid or Klaviyo account they already use.
- Sell it on day one: plans, trials, quotas and five payment gateways are built in
- Make it yours: your name, logo, colours, favicon, legal pages and domain on every screen
- Own it: full readable source code, plus a prebuilt version you can run as is
An editor your customers will pay for
- Drag and drop, tap on a phone, or press Enter: every block can be inserted three ways
- 25 email-safe blocks: headings, images, buttons, pricing cards, data tables, testimonials, image collages, ratings, progress bars, QR codes, barcodes, charts and more, plus 10 ready layouts
- 79 hand-designed templates across commerce, newsletters, events, announcements and transactional email
- Every setting in one inspector, with separate values for phones
- Nine one-click themes and a brand kit per workspace: change a colour once and every design follows
- Email checks as you edit: missing alt text, empty links, phone layout problems and Gmail's 102 KB clipping limit
- Test sends to verified addresses only
An AI assistant that knows the brand
- Draft a whole, editable email from a one-line brief
- Rewrite, shorten, or make any text friendlier or more formal, in the voice of the workspace's brand kit
- Write headings and button text, and suggest subject lines
- Generate images into the media library, and write alt text for every image
- Bring your own key: any OpenAI-compatible provider or Anthropic
- AI requests and generated images are plan quotas, so AI can be an upgrade you charge for
Edit on any screen, lose nothing
- A real editor on phones: select, insert and restyle blocks at 390 px wide
- True phone preview of every email
- Edits made offline stay on the device and save when the connection returns
- Every save is a revision you can restore; step-by-step undo and redo
- Conflict recovery when two people edit the same design
One design, every sending platform
- Six exports: HTML with styles inlined, HTML with a style block, ZIP with images, EML, plain text and re-importable JSON
- Table-based, inline-styled HTML built for Gmail, Outlook and Apple Mail
- Merge tags rewritten for the platform you choose: Mailchimp, Brevo, Klaviyo, SendGrid, HubSpot or generic
- One-click publish to Mailchimp, Brevo, SendGrid and Klaviyo as a template or unsent draft
Run the business from one console
- Overview of tenants, subscriptions, monthly recurring revenue and growth
- Plans with trials and per-plan limits: designs, storage, seats, AI requests and images, exports, test sends and template tiers
- Payments through Stripe, PayPal, Razorpay or Paystack, or manual transfer with proof upload and approval; payment recovery for failed renewals
- Tenants and users: change plans, suspend, reinstate, transfer ownership, delete
- Template library: publish, hide, reorder, re-tier and add your own
- Branding, SMTP, storage (local disk or any S3-compatible bucket), AI, publishing platforms, merge tags and legal pages, all from the panel
- Public marketing site with pricing, a template gallery, contact and legal pages, ready for your domain
- Staff roles, an audit log, a log viewer and a security checklist
Built to be maintained
- Next.js 16, React 19, TypeScript in strict mode, Tailwind CSS and shadcn/ui
- PostgreSQL with tenant isolation enforced by row-level security, not only in application code
- More than 3,000 automated tests, including 500+ security tests for isolation, SSRF, uploads and injection
- One Node.js process and one database: no Redis, queue or background worker
- Gateway, SMTP and AI keys encrypted at rest
- Every interface string in one English messages file, ready for translation
Installation
- A six-step web installer: it checks the server, creates the database tables and your operator account, and tests your mail
- Illustrated guides for cPanel (Setup Node.js App), a VPS (one command, HTTPS included), Vercel and Render
- Settings live in the panel or a .env file; changing them never needs a rebuild
Server Requirements
- Node.js 20 or newer (22 recommended)
- PostgreSQL 14 or newer
- cPanel Node.js hosting, a VPS, Vercel or Render
- S3-compatible storage on serverless hosts; local disk elsewhere
- No Redis, queue or background worker
Required API Keys
- SMTP credentials for account emails (optional)
- OpenAI-compatible or Anthropic API key for AI features (optional)
- Stripe, PayPal, Razorpay or Paystack keys for payments (optional)
Screenshots & Dashboards
Which Licence
| What you get | Regular$99 | Extended$499 |
|---|---|---|
| End products you may build | 1 | 1 |
| Charge your end users | ||
| Full source code | ||
| Private repository access | ||
| White-label with your own brand | ||
| Updates | 12 months | 12 months |
| Resell the source code itself | ||
| Managed installation | Add-on | Add-on |
The difference that matters: the Extended Licence is the only one that lets you charge your end users. Full terms on the licence page.
Read the documentation
Full setup, configuration, and API reference — public, before you buy.
Changelog
- Initial release
Questions Before You Buy
- Getting the product running on your server
- Bug fixes in the source code we shipped
- Answering questions about the codebase
- Custom feature development (quoted separately)
- Your API costs (OpenAI, OpenRouter, Serper and similar)
- Your server and hosting costs
- Setting up your third-party accounts
Do I need a VPS to run this?
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Yes. These platforms use background workers, queues, and scheduled jobs, so they need a persistent Linux server rather than serverless hosting. A $12/month VPS is enough to start. If you would rather not manage it, add managed installation at checkout and we will deploy it for you.
What happens if the installation fails?
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If you bought managed installation, we keep working until it runs — that is what you paid for. If you are self-installing and hit a genuine bug in our code, we fix it. If you are stuck on your own server configuration, we will point you in the right direction, and you can upgrade to managed installation at any time.
How long do I get updates?
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12 months from purchase. Your licence to use the product never expires — only access to new versions does. We will email you when a new release is available while your window is open.
Can I resell this?
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You can sell the end product you build with it, but only on the Extended Licence. Neither licence lets you resell the source code itself, or list it on a marketplace as your own item.
Who pays for the API keys?
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You do, directly to the provider. Every product uses a bring-your-own-keys model, which is the point: you pay raw API rates instead of a marked-up subscription, and we never see your data or your keys.
What exactly does support cover?
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We make it run on your server and we fix bugs in the code we shipped. Not included: custom features, your API costs, your server costs, or setting up your third-party accounts. Custom work is quoted separately.
Can I remove your branding?
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Yes. Both licences allow full white-labelling — your logo, your colours, your product name. There is no attribution requirement and no hidden branding in the codebase.
What is your refund policy?
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14 days. If the product does not do what this page says it does, email us and we will refund you in full. Because you receive the complete source code on purchase, we cannot refund simply because you changed your mind after downloading it — so please use the live demo first.
Does Mailnib send email campaigns?
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No. Mailnib designs and exports email. Your customers export HTML or publish to Mailchimp, Brevo, SendGrid or Klaviyo as a template or unsent draft, and send from the platform they already use. Test sends go to verified addresses only.
What is in the download?
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A prebuilt runtime you can upload and run as is, the complete readable source code with its lockfile and tools, the full illustrated documentation for offline reading, and a one-command installer for Ubuntu or Debian servers.
Will it run on shared cPanel hosting?
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Yes, on any cPanel host with Setup Node.js App, Node.js 20 or newer and PostgreSQL 14 or newer. It needs no Redis, queue or background worker. On serverless hosts such as Vercel, uploads go to S3-compatible storage.
Are the sample photos included?
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No. Sample photographs in the demo, video and screenshots are for preview only. Templates ship with drawn placeholders and can load photos from your own host.
Not ready to buy?
We'll send the complete Mailnib feature list, the documentation, and demo logins so you can evaluate it properly. No sequence of sales emails, and you can unsubscribe in one click.
Source Code Licence
Technical Specifications
Need Custom Build?
Need a feature this doesn't have, or a system built from scratch? Book a 20-minute call and we'll scope it.