How to Build a Newsletter Platform Like Beehiiv or Substack

Newsletters are not new, but the tooling around them has changed completely. Substack proved that writers could earn a living from paid email subscriptions. Beehiiv proved that creators wanted more than just a subscribe button and a paywall. They wanted growth tools, ad revenue, referral programs, and real analytics. Beehiiv crossed $25M in annual recurring revenue by building all of those features and targeting newsletter operators who treat their publication like a business, not a hobby.

ConvertKit (now Kit) serves course creators and coaches. Ghost targets independent publishers who want full ownership. Buttondown appeals to developers who want something minimal. Each of these platforms carved out a niche because the "newsletter platform" category is actually several distinct products wearing the same label.

The opportunity for new entrants is in vertical specialization. A newsletter platform built specifically for B2B media companies, local news organizations, corporate communications teams, or niche hobbyist publishers can win by solving their specific problems better than any horizontal tool. The core infrastructure is the same, but the features you prioritize and the workflows you optimize will vary dramatically.

If you are building in this space, you need to understand one thing above all else: email deliverability is your product. A beautiful editor and slick analytics dashboard mean nothing if your emails land in spam. Every technical decision you make should be evaluated through the lens of "does this help or hurt deliverability?" That single question will guide you through hundreds of architecture decisions.

Deliverability is the hardest and most important part of building a newsletter platform. It is not a feature you add later. It is the core of your architecture. Get this wrong and nothing else matters.

SPF, DKIM, and DMARC: The Authentication Trifecta

Every email you send must pass three authentication checks. SPF (Sender Policy Framework) tells receiving mail servers which IP addresses are authorized to send on behalf of your domain. DKIM (DomainKeys Identified Mail) adds a cryptographic signature to each email, proving it was not tampered with in transit. DMARC (Domain-based Message Authentication, Reporting, and Conformance) ties SPF and DKIM together and tells receiving servers what to do when authentication fails (quarantine, reject, or do nothing).

For a multi-tenant newsletter platform, this gets complicated. Each creator who uses a custom sending domain needs their own SPF, DKIM, and DMARC records. Your onboarding flow must guide creators through adding DNS records, then validate those records programmatically. Build a DNS verification service that checks records every few hours and alerts creators if their authentication breaks. Google and Yahoo both started enforcing stricter DMARC policies in 2024, and that trend is only accelerating.

IP Warming and Reputation Management

New IP addresses have no sending reputation, which means mailbox providers like Gmail and Outlook will throttle or junk your emails until you prove you are a legitimate sender. IP warming is the process of gradually increasing your sending volume on a new IP over 4 to 8 weeks. Start with 500 emails per day and double every few days, monitoring bounce rates and spam complaints at each step.

You need dedicated IP pools for different quality tiers. Creators with high engagement (low spam complaints, high open rates) should send from your premium IP pool. New or lower-quality senders should use a separate pool so their reputation does not drag down your best senders. Postmark and SendGrid both offer dedicated IP management, but at scale you will want to manage your own IPs through AWS SES or a direct relationship with an SMTP provider.

Bounce and Complaint Processing

Hard bounces (invalid email addresses) must be removed from lists immediately. Soft bounces (full mailboxes, temporary server issues) should be retried 3 to 5 times over 72 hours, then suppressed. Spam complaints (when a recipient clicks "Report Spam") are the most damaging signal. If your complaint rate exceeds 0.1% on Gmail, you will see immediate deliverability degradation. Build a feedback loop processor that ingests complaint reports from major ISPs via ARF (Abuse Reporting Format) and automatically unsubscribes complainers.

Budget $40K to $80K for deliverability infrastructure if you are building in-house. Or use a combination of AWS SES ($0.10 per 1,000 emails) for volume sending and Postmark ($1.25 per 1,000 emails) for transactional emails like signup confirmations and password resets. Many platforms use a hybrid approach: SES for bulk newsletter sends and a premium provider for transactional mail where deliverability is non-negotiable.

Your subscriber management system is the second most critical piece of infrastructure after deliverability. Newsletter creators live in their subscriber lists. They need to import, segment, tag, clean, and analyze their audience constantly.

Import and Migration Tools

Every newsletter creator switching to your platform will bring an existing list. Support CSV import with intelligent column mapping (auto-detect email, first name, last name, tags, subscription date). But CSV is just the baseline. Build native migration tools for Mailchimp, ConvertKit, Substack, and Beehiiv. These should pull subscriber data, tags, segments, and ideally engagement history through each platform's API. A smooth migration experience is one of the strongest levers for customer acquisition. If switching is painless, creators will switch.

Segmentation and Tagging

Support both manual tags (creator-applied labels like "VIP" or "Purchased Course A") and behavioral segments (auto-generated groups based on actions like "opened last 5 emails" or "clicked a link in the past 30 days"). Segments should update in real time or near-real time. A creator should be able to send a campaign to "subscribers who opened at least 3 of my last 10 emails AND are tagged as Premium" and have that segment calculated in seconds, even with 500K subscribers.

Use a combination of PostgreSQL for subscriber records and a columnar store like ClickHouse or DuckDB for engagement analytics. PostgreSQL handles the CRUD operations and tag management well, but running complex engagement queries across millions of event rows will be painfully slow without a purpose-built analytics database.

List Hygiene and Compliance

Inactive subscribers kill deliverability. Build automated list hygiene that identifies subscribers who have not opened or clicked in 90+ days. Prompt creators to run re-engagement campaigns, then automatically suppress subscribers who remain inactive after the re-engagement attempt. This is controversial because creators hate seeing their subscriber count drop, but it is essential for maintaining sender reputation.

On the compliance side, you need CAN-SPAM and GDPR compliance baked into the product. Every email must include a one-click unsubscribe link (RFC 8058, now enforced by Gmail and Yahoo). Support double opt-in as a configurable option. Maintain a global suppression list across your platform so unsubscribed or bounced addresses never receive email again, even if they appear on a different creator's import file. Budget $30K to $50K for subscriber management.

Newsletter creators spend most of their time in the editor. If your writing experience is clunky, slow, or limiting, they will leave. This is where Substack initially won: they made writing a newsletter feel as simple as writing a blog post.

Rich Text Editor Architecture

Build your editor on Tiptap or Lexical (Meta's open-source editor). Both support collaborative editing, custom extensions, and output to HTML. Avoid building a custom editor from scratch. That is a 6 to 12 month project on its own. Tiptap has a better extension ecosystem and more community support. Lexical is more performant for very long documents but has a steeper learning curve.

Your editor needs to output clean, email-safe HTML. This is the tricky part. Email clients (especially Outlook) support a limited and inconsistent subset of HTML and CSS. You need an HTML transformation pipeline that converts your editor's output into email-compatible markup. Use inline CSS (no external stylesheets), table-based layouts for complex structures, and fallback fonts. Tools like MJML or Maizzle can help generate email-safe HTML from a more modern markup format.

Template System

Offer pre-built templates that creators can customize with their brand colors, logo, and fonts. Support a header image, branded footer with social links, and configurable layout blocks (text, image, divider, button, social links). Let creators save their own templates. Most newsletter creators settle on one layout and use it for every issue, so the template system does not need to be a full drag-and-drop page builder. Keep it focused and fast.

Preview and Testing

Build a preview system that shows how the email will render across major clients: Gmail (web and mobile), Apple Mail, Outlook (desktop and web), and Yahoo Mail. You can use Litmus or Email on Acid APIs to generate these previews, though they are expensive ($100 to $500/month). At minimum, build a web preview and a plain-text preview. Let creators send test emails to their own address before publishing.

Scheduling and Automation

Time-zone-aware scheduling is table stakes. A creator in New York targeting a global audience should be able to schedule a send for "9 AM in each subscriber's local time zone." This means your sending system needs to batch sends by time zone. Also build welcome sequences (a series of emails sent to new subscribers on a schedule) and RSS-to-email automation for creators who also publish blog content. Budget $25K to $45K for the editorial CMS.

Monetization is where Beehiiv separated itself from Substack. Substack offers paid subscriptions and takes 10%. Beehiiv offers paid subscriptions, a referral program engine, an ad network, and premium analytics, then lets creators keep a larger share. If you are building a newsletter platform, you need to support multiple revenue streams for creators.

Paid Subscription Billing

Use Stripe Connect to handle payments between subscribers and creators. The "Express" account type works well: creators connect their Stripe account through your OAuth flow, and you take a platform fee (typically 5 to 10%) on each transaction. Support monthly and annual plans, with annual pricing at a 15 to 20% discount. Build a paywall system that gates premium content based on subscription status. The paywall should work both in email (show a teaser with a "subscribe to read more" CTA) and on the web version of the newsletter. For implementation details, check out our subscription billing guide.

Referral Program Engine

Beehiiv's referral program is one of its killer features. Subscribers share a unique referral link, and when their friends subscribe, the referrer earns rewards (unlockable content, merchandise, or milestone badges). The technical implementation requires a referral tracking system: generate a unique link per subscriber, track clicks and conversions with a cookie and UTM-based attribution model, and trigger reward fulfillment at configurable milestones (3 referrals, 10 referrals, 25 referrals).

Build a referral dashboard where creators can configure their reward tiers, view referral leaderboards, and manage reward fulfillment. The reward system should support digital rewards (exclusive content, bonus newsletters), physical rewards (via integration with a fulfillment service like Printful), and custom rewards (a 1-on-1 call with the creator). This feature alone can drive 10 to 30% of subscriber growth for active newsletter operators. Budget $20K to $35K for a referral engine. Our guide on building referral programs covers the full architecture.

Ad Network and Sponsorship Marketplace

Newsletter advertising is a massive market. Beehiiv built their own ad network that matches advertisers with newsletter creators based on audience demographics and niche. Building a full ad network is a significant undertaking (budget $60K to $100K), but you can start with a simpler sponsorship marketplace: let advertisers browse newsletter profiles, view audience metrics, and book sponsorship placements directly.

The ad insertion system needs to support native ad blocks within the newsletter template. Creators should be able to place an "ad slot" in their template, and the system fills it with a matched ad or sponsored content. Track impressions, clicks, and conversion metrics for each placement. Advertisers pay CPM ($5 to $50 depending on niche) or CPC ($0.50 to $5.00), and the platform takes 10 to 20% of ad revenue.

These features round out the platform and differentiate a professional newsletter tool from a basic email sender.

Custom Domain Support

Creators want their newsletter to live on their own domain (newsletter.theirsite.com), not on yourplatform.com/their-newsletter. Support custom domains for both the web publication (the archive of past issues) and the sending domain (so emails come from hello@theirbrand.com, not noreply@yourplatform.com). Custom sending domains require automated DNS record provisioning for SPF, DKIM, and CNAME records. Use Cloudflare's API or AWS Route 53 for programmatic DNS management if you are handling DNS on behalf of creators. Otherwise, provide clear step-by-step instructions and a verification tool that checks records and reports issues in plain language.

Analytics Dashboard

Newsletter creators are obsessed with metrics. Your analytics dashboard needs to cover: open rates (with Apple Mail Privacy Protection caveats), click rates by link, subscriber growth over time, unsubscribe trends, geographic distribution of opens, device and client breakdown, revenue metrics (for paid newsletters), and referral program performance. Real-time stats for the first hour after a send are critical. Creators refresh their stats constantly after hitting "send."

Use ClickHouse or TimescaleDB for analytics storage. Each email send generates at least 3 to 5 events (send, delivery, open, click, unsubscribe), and at scale (1M subscribers, weekly sends) you are processing 15 to 25 million events per month per creator. PostgreSQL will buckle under this workload. ClickHouse handles time-series analytics queries on billions of rows in milliseconds. Budget $25K to $40K for analytics.

Growth Tools

Beyond referral programs, build tools that help creators grow their subscriber list. Embeddable signup forms (JavaScript widget that creators paste on their website). Landing page builder for creators who do not have a website. Recommendations network where newsletters cross-promote each other (Substack's "Recommendations" feature drove significant cross-pollination growth). Social sharing cards with dynamic Open Graph images that show the newsletter title and subscriber count. Magic link authentication so subscribers never need to remember a password. These features individually are small, but together they create a growth toolkit that keeps creators on your platform.

Here is a production-ready architecture for a newsletter platform that can handle millions of subscribers and tens of millions of email sends per month.

Recommended Tech Stack

• Frontend: Next.js with React Server Components for the creator dashboard and public newsletter pages
• Editor: Tiptap with custom extensions for email-specific blocks (ad slots, paywall breaks, referral widgets)
• API: Node.js with Hono or Fastify for the REST/GraphQL API layer
• Database: PostgreSQL (Neon or Supabase) for subscriber data, newsletter content, and creator accounts
• Analytics Store: ClickHouse for email event tracking (opens, clicks, bounces, complaints)
• Queue: Redis with BullMQ or AWS SQS for email send job queuing and scheduling
• Email Sending: AWS SES for bulk sends ($0.10/1K emails), Postmark for transactional ($1.25/1K emails)
• Storage: Cloudflare R2 or AWS S3 for images and file attachments
• Payments: Stripe Connect for creator payouts and subscriber billing
• Hosting: Vercel for the frontend, Railway or Fly.io for the API and worker services

The Email Sending Pipeline

When a creator hits "Send" on a newsletter with 500K subscribers, here is what happens:

1. The API creates a "campaign" record and enqueues a batch job. 2. The batch worker splits the subscriber list into chunks of 1,000 to 5,000. 3. For each chunk, it renders the email HTML (personalizing merge fields like first name and referral link), then submits the batch to your ESP (SES or equivalent). 4. The ESP returns delivery status callbacks via webhooks. 5. Your webhook processor ingests delivery, bounce, open, and click events into ClickHouse. 6. The analytics dashboard queries ClickHouse to show real-time campaign performance.

At 500K subscribers, this entire flow should complete in 10 to 30 minutes depending on your SES sending rate (which starts at 200 emails/second and can be increased to 1,000+ by request). The key to reliability is idempotent job processing. If a worker crashes mid-batch, another worker should pick up the remaining chunks without sending duplicates. Use a "sent" flag per subscriber per campaign in your database to prevent double-sends.

Scaling Considerations

At 10M+ total subscribers across your platform, you will hit several scaling challenges. SES rate limits require you to apply for production access and gradually increase your sending quota. Webhook ingestion at peak (millions of events in minutes after a large send) needs a buffer, so use SQS or Kafka between the webhook endpoint and your event processor. Analytics queries will slow down without proper ClickHouse table partitioning (partition by month) and materialized views for common aggregations like daily open rates.

Plan for multi-region deployment once you have significant international traffic. Email deliverability is influenced by the geographic proximity of your sending servers to the receiving mail servers. Sending from US-East to European recipients adds latency and can affect throughput. Deploy SES in eu-west-1 for European sends and us-east-1 for North American sends.

Timeline and Budget

A full-featured newsletter platform (editorial CMS, deliverability infrastructure, subscriber management, paid subscriptions, referral engine, analytics, custom domains) takes 6 to 9 months with a team of 3 to 5 engineers. Budget $250K to $450K for the initial build. You can ship an MVP (editor, sending, basic analytics, signup forms) in 10 to 14 weeks for $80K to $150K, then layer on monetization and growth features iteratively.

The newsletter market rewards platforms that nail deliverability first and features second. Creators will tolerate a basic editor if their open rates are high. They will not tolerate a beautiful editor if their emails land in spam. Start with the infrastructure and build the polish on top.

If you are serious about building a newsletter platform or want to validate your concept with an MVP, book a free strategy call and we will walk you through the architecture decisions that matter most for your specific use case.