PostHog gives you product analytics, feature flags, session replays, and experiments in one open-source package. What it doesn't give you is email. And if you're building a product-led SaaS, the gap between "knowing what users do" and "emailing them about it" is where a lot of growth happens.

The good news is that PostHog tracks the exact events you'd want to trigger emails on: user signed up, feature used, trial expiring, onboarding step completed. The challenge is getting those events into an email platform that can actually do something with them.

Here's how the best email tools connect with PostHog.

How PostHog + Email Integration Works

PostHog doesn't have a native email sending feature (they've said they won't build one). So you need to get PostHog data into an email tool. There are four main approaches:

Webhooks from PostHog Actions: PostHog can fire a webhook when an Action triggers. Set up an Action for the event you care about, add a webhook destination, and point it at your email platform's API. This is best for specific, high-value events where you want email responses.
PostHog CDP (Customer Data Platform): PostHog's CDP feature lets you route events to destinations including email platforms. This is the cleanest approach for real-time event routing and the one PostHog recommends.
Shared event tracking: Track events to both PostHog and your email tool from your application code. This is the most common approach since you control exactly what goes where. If you're already sending emails based on product events, adding PostHog to the same tracking calls is straightforward.
Batch exports: Export PostHog cohorts periodically and sync them to your email platform's segments. Less real-time but works for campaign-based use cases.

Why PostHog Users Need a Dedicated Email Tool

PostHog's philosophy is to be the best product analytics platform, not to do everything. They've explicitly chosen not to build email sending because dedicated email tools do it better. This means the PostHog + email tool combination isn't a compromise; it's the intended architecture.

The teams using PostHog tend to be technical, product-led, and developer-first. They want tools with clean APIs, good documentation, and minimal vendor lock-in. This profile shapes which email tools pair well with PostHog. Enterprise platforms with complex onboarding and mandatory sales calls are a poor fit. Developer-friendly tools with event-driven APIs are a natural match.

The 6 Best Options

1. Sequenzy

Best for: SaaS founders wanting PostHog events to drive lifecycle email

Sequenzy's event API accepts the same kinds of events PostHog tracks. The integration pattern is straightforward: track events to both PostHog (for analytics) and Sequenzy (for email automation) from your application code. When a user completes onboarding, hits a usage milestone, or triggers a billing event, Sequenzy starts the right email sequence.

The overlap between PostHog users and Sequenzy users is natural. Both tools target developers building SaaS products. Both are event-driven. And Sequenzy's Stripe integration handles payment events automatically, so you only need to manually track product usage events.

What makes Sequenzy particularly well-suited for PostHog users is the shared philosophy of simplicity. PostHog users chose PostHog because it's straightforward and developer-friendly. Sequenzy follows the same approach with email: send events, trigger sequences, done. No enterprise onboarding, no mandatory sales calls, no complex workflow builder to learn.

The practical setup takes about 30 minutes: add Sequenzy's event tracking alongside your PostHog calls, map a few key events to sequences, and you have lifecycle email running. For SaaS companies, the pre-built lifecycle patterns (trial conversion, dunning, onboarding) mean you're not starting from a blank canvas.

Pricing: From $29/month Integration: Shared event tracking from application code, or PostHog webhook to Sequenzy API Pros: Event-driven like PostHog, SaaS lifecycle focus, Stripe handles payment events, simple API, fast setup Cons: No native PostHog destination, newer platform

2. Customer.io

Best for: Technical teams wanting the deepest event-driven email automation

Customer.io is the most event-driven email platform on the market, which makes it a natural pairing with PostHog. You can route PostHog events to Customer.io via the PostHog CDP, webhooks, or shared application-level tracking.

Once events arrive in Customer.io, the automation possibilities are extensive. Trigger campaigns based on event combinations, use event properties for personalization, build complex branching workflows. If PostHog is your analytics brain, Customer.io can be your email brain.

The combination is powerful for teams that want to build sophisticated, data-driven email programs. For example, you can use PostHog to identify that users who complete three specific actions within their first week have 4x higher retention. Then you can build a Customer.io workflow that monitors those actions and sends targeted encouragement to users who've completed one or two but not all three.

Customer.io also supports webhook-based integrations natively, which pairs well with PostHog's webhook feature. You can set up PostHog Actions for specific behavioral patterns and have them trigger Customer.io campaigns directly.

The downside is the combined cost and complexity. Customer.io starts at $100/month, and the setup requires engineering time to configure event routing, build workflows, and maintain the integration. For well-resourced teams, this investment pays off. For lean startups, simpler options might be more appropriate.

Pricing: From $100/month Integration: PostHog CDP destination, webhooks, or shared event tracking Pros: Most flexible automations, deep event handling, visual workflow builder, API-first, powerful segmentation Cons: Expensive, steep learning curve, can be overengineered for simple needs

3. Loops

Best for: Early-stage SaaS wanting simple event-to-email automation

Loops is built for the same audience that loves PostHog: developers building SaaS products. The integration works through shared event tracking. Track events to PostHog for analytics and to Loops for email triggers. Loops' event model is simple and maps well to PostHog events.

The simplicity is the selling point. Where Customer.io gives you a visual workflow builder with dozens of options, Loops gives you event-triggered sequences that just work. For a startup that wants "when user does X, send email Y" without building a complex automation engine, Loops delivers.

Loops and PostHog share a design philosophy: do fewer things, but do them well. PostHog doesn't try to be an email tool. Loops doesn't try to be an analytics platform. The combination respects the boundaries of each tool and keeps your stack lean.

The trade-off is that you'll outgrow Loops faster than you'll outgrow PostHog. PostHog's analytics capabilities scale to large, complex products. Loops' email capabilities are designed for simpler use cases. When you need conditional branching, multi-step workflows with A/B testing, or cohort-based campaigns, you'll need to migrate to a more capable email tool.

Pricing: Free for 1,000 contacts, from $49/month Integration: Shared event tracking from application code Pros: Simple, developer-friendly, good free tier, event-driven model, fast setup Cons: Basic automations, limited segmentation, no direct PostHog integration, limited lifecycle patterns

4. Resend

Best for: Developers wanting PostHog analytics with clean transactional email

Resend handles transactional email (welcome emails, password resets, notifications) with the best developer experience available. Combined with PostHog, you get analytics on user behavior plus reliable email delivery for the messages that matter most.

The integration is at the application level: your app tracks events to PostHog and sends emails via Resend in the same request handlers. Resend doesn't have automations or sequences, so it's purely for transactional email. You'd need a separate tool for marketing and lifecycle emails.

Resend's appeal to PostHog users is the developer experience. React Email templates, TypeScript SDKs, clean REST API, and documentation that developers actually enjoy reading. If your team builds with React and TypeScript (common in PostHog's user base), the email templating workflow feels native.

For early-stage startups, Resend + PostHog can be enough. You send welcome emails, password resets, and basic notifications via Resend. You track everything in PostHog. As your email needs grow beyond transactional messages, you add a marketing email tool (Sequenzy, Loops, or Customer.io) to handle sequences and campaigns.

Pricing: Free for 100 emails/day, from $20/month Integration: Application-level (both called from your code) Pros: Best DX, React Email, TypeScript-first, fast delivery, clean API Cons: No automations, no marketing email, transactional only, requires additional tool for lifecycle email

5. Brevo (formerly Sendinblue)

Best for: Teams wanting an affordable all-in-one alongside PostHog

Brevo offers email, SMS, and basic automation at a lower price point than most competitors. You can route PostHog events to Brevo via webhooks or application-level tracking. Brevo's automation workflows can trigger on custom events, though the event handling isn't as sophisticated as Customer.io.

The value proposition is breadth at a low price. If you need email marketing, transactional email, and SMS alongside PostHog analytics, Brevo covers all three without enterprise pricing.

Brevo isn't the most polished option on this list, and its automation capabilities are middle-of-the-road. But for teams that want to consolidate email sending (transactional + marketing) into one affordable tool while keeping PostHog for analytics, it delivers good value. The generous free tier (300 emails/day) lets you validate the setup before committing.

Pricing: Free for 300 emails/day, from $9/month Integration: Webhooks or shared event tracking Pros: Affordable, transactional + marketing, SMS included, generous free tier, multi-channel Cons: Less polished than focused tools, automation depth limited, UI can feel clunky, not developer-first

6. Mailgun

Best for: Developers wanting PostHog analytics with reliable email infrastructure

Mailgun provides email infrastructure (sending APIs, deliverability tools, inbound processing) that pairs with PostHog as a pure analytics layer. Your app uses PostHog to understand user behavior and Mailgun to send the resulting emails.

Mailgun is infrastructure, not a marketing platform. There are no visual editors, no drag-and-drop automations, no campaign builders. You build everything in code. For developers who prefer that approach, the PostHog + Mailgun combination gives you analytics and email without any marketing platform overhead.

This is the most hands-on option on the list. You write all the automation logic yourself. You build the email templates in code. You manage the sending logic. The advantage is complete control. The disadvantage is that every email workflow requires engineering time.

Mailgun makes sense for teams with specific deliverability requirements (custom IP pools, dedicated IPs, advanced DNS configuration) or teams that want to build their own email automation layer on top of reliable sending infrastructure. If your thinking leans more toward "build vs. buy" for email, Mailgun gives you the infrastructure to build on.

Pricing: Free for 100 emails/day, from $15/month (Flex plan) Integration: Application-level (both called from your code) Pros: Developer-focused, reliable infrastructure, good APIs, inbound email processing, full control Cons: No marketing features, everything built in code, no automations, requires engineering for every workflow

Integration Patterns

Pattern 1: Shared Event Tracking (Most Common)

Your application code tracks events to both PostHog and your email tool:

User action -> Your app -> PostHog (analytics) + Email tool (automation)

This is the most reliable approach. You control exactly what data goes where, and there's no dependency between the two services. If PostHog goes down, your email tool still receives events (and vice versa).

When to use: Always a safe choice. Especially good when you want full control over which events go to each system.

Implementation tip: Create a wrapper function in your application code that sends events to both services. This keeps the dual-tracking logic in one place:

function trackEvent(name, properties, user) {
  posthog.capture(name, properties)
  emailTool.trackEvent(user.email, name, properties)
}

Pattern 2: PostHog CDP Routing

PostHog's CDP routes events to your email tool as a destination:

User action -> PostHog -> CDP -> Email tool

Cleaner instrumentation (one tracking call instead of two), but adds a dependency on PostHog's CDP infrastructure. Works well for Customer.io and other tools with CDP support.

When to use: When you want single-point instrumentation and don't mind the dependency on PostHog's CDP infrastructure. Good for teams already using PostHog's CDP for other destinations.

Pattern 3: PostHog Webhooks

PostHog fires webhooks when specific Actions trigger:

User action -> PostHog -> Action triggers -> Webhook -> Email tool API

Good for specific, high-value events (trial started, subscription cancelled) rather than high-volume event streaming. PostHog's webhook delivery is reliable but not designed for streaming every page view.

When to use: When you only need a few specific events to trigger emails. Good for getting started quickly without setting up full event routing.

Choosing the Right Pattern

Starting out? Use shared event tracking. It's the simplest and most reliable.
Already using PostHog CDP? Add your email tool as a CDP destination.
Need just a few specific triggers? Use PostHog webhooks for those specific events.
Doing all three? That's overkill. Pick one primary pattern and stick with it.

How to Choose

You're a SaaS founder wanting lifecycle email: Sequenzy. Track product events to both PostHog and Sequenzy. Let Stripe handle payment events automatically. Best for SaaS lifecycle marketing without over-engineering.

You need complex event-driven automations: Customer.io. The deepest automation engine paired with PostHog's analytics gives you full control. Best for technical teams with sophisticated workflow requirements.

You want simple and fast: Loops. Event-driven email without the complexity. Best for early-stage startups that want to set up email in an afternoon.

You only need transactional email: Resend. Best DX for sending individual emails alongside PostHog analytics. Best for teams that haven't yet needed marketing email.

You want everything cheap: Brevo. Email, SMS, and basic automation at the lowest price point. Best for budget-conscious teams that need multi-channel messaging.

You want pure infrastructure: Mailgun. APIs for sending, PostHog for analytics, everything in code. Best for teams that want to build their own email automation layer.

FAQ

Can PostHog send emails directly? No. PostHog is explicitly a product analytics tool and has stated they won't build email sending. You need a separate email platform. This isn't a limitation; it's a design choice. PostHog focuses on analytics, and dedicated email tools focus on email. The combination is better than either tool trying to do both.

Should I track events twice (PostHog + email tool)? For most teams, yes. It's the simplest, most reliable approach. The alternative is routing events through PostHog's CDP, which works but adds complexity and a dependency. Tracking events twice sounds wasteful, but the overhead is minimal (two API calls instead of one) and the independence is valuable.

Can I use PostHog cohorts for email targeting? You can export PostHog cohorts and import them into your email platform as segments. This works for campaign-based targeting but isn't real-time. For real-time triggers, use event-based automations. PostHog cohorts are particularly useful for re-engagement campaigns targeting users who match specific behavioral patterns over time.

What events should I send to my email tool? Only events that trigger emails or update contact profiles. Your email tool doesn't need page views, button clicks, or session data. Focus on: account created, trial started, onboarding step completed, feature first used, subscription changed, and similar high-value events. A good rule of thumb: if you can't imagine sending an email in response to this event, don't send it to your email tool.

How do I handle PostHog's anonymous users in my email tool? PostHog tracks anonymous users before they sign up. Your email tool can't email anonymous users (no email address). The integration only matters after the user is identified. In your shared event tracking code, only send events to the email tool when you have an email address. PostHog will track both anonymous and identified users, but the email tool only receives identified ones.

Can I use PostHog feature flags to control email content? Not directly, but you can use PostHog feature flag assignments as event properties. When tracking an event to your email tool, include the user's feature flag state as a property. Your email tool can then use those properties for conditional content or branching logic. This is useful for coordinating in-product experiments with email messaging.

What's the best PostHog + email stack for a solo founder? PostHog (free tier) + Sequenzy ($29/month) or PostHog (free tier) + Loops (free tier). Both combinations give you product analytics and email automation for under $30/month. Start with the free tiers, and upgrade as you grow. Add Resend (free tier) if you need transactional email separately.

How do I measure whether my email integration with PostHog is working? Track conversion events in PostHog for the actions your emails are trying to drive. If you send an onboarding email about Feature X, track whether recipients actually use Feature X within 48 hours. Compare conversion rates for users who received the email vs. those who didn't. PostHog's funnel analysis makes this comparison straightforward. Tracking the right email marketing KPIs matters more than sophisticated tooling.