What is the difference between Substack and Plunk?

Substack is best for Writers who want to monetize with paid subscriptions, while Plunk is best for Developers wanting open-source transactional email. Substack starts at Free and Plunk starts at Free.

Is Substack or Plunk cheaper?

Substack starts at Free and is free. Plunk starts at Free and is free.

Is there a free alternative to Plunk?

Both Substack and Plunk offer free tiers.

Substack vs Plunk

Substack is newsletter and publishing platform with built-in paid subscriptions, while Plunk is open-source email platform for transactional and marketing emails with automation. Plunk is open source and can be self-hosted, giving you full control over your data. Substack is built for writers who want to monetize with paid subscriptions, whereas Plunk targets developers wanting open-source transactional email.

At a glance

	Substack	Plunk
Best for	Writers who want to monetize with paid subscriptions	Developers wanting open-source transactional email
Starting price	Free	Free
Free tier	✓	✓
Open source	—	✓
Free tier available	✓	✓
Open source	—	✓
Analytics	—	✓
Automations	—	✓
Community	✓	—
Discovery Network	✓	—
Mobile App	✓	—
Open Source	—	✓
Paid Subscriptions	✓	—
Podcasts	✓	—
Transactional	—	✓

Substack

Strengths

Free to use — takes 10% of paid subscriber revenue
Built-in discovery and recommendation network
Simple, distraction-free writing experience
Mobile app for readers

Weaknesses

10% revenue cut is steep at scale
Very limited customization
Basic analytics
No automation or segmentation

Try Substack → Full review

Plunk

Strengths

Open source and transparent
Open-source codebase gives you full transparency and community-driven development
Fully open-source — you can self-host, audit the code, and avoid vendor lock-in
The core product is free with no paywalled essentials

Weaknesses

May lack some advanced features
Self-hosting is free but requires server maintenance and DevOps knowledge
Fewer built-in features means you may need additional tools to cover gaps
Deliverability depends on your sender reputation, which takes time to build

Try Plunk → Full review

The bottom line

Pricing: Both Substack and Plunk are free, so this decision comes down to features and philosophy rather than budget.

Feature gaps: Substack offers Community, Discovery Network and Mobile App that Plunk lacks. Plunk brings Analytics, Automations and Open Source that Substack does not have.

Team fit: Substack is geared toward individual users and small setups, while Plunk is aimed at small teams teams. Pick the one that matches where your team is today and where it is headed — migrating tools later is always painful.

Open source: Plunk is open source, meaning you can self-host, audit the code, and avoid vendor lock-in. Substack is proprietary — you are trusting the vendor with your data and uptime.

Where each tool shines: Substack's biggest strengths are: free to use — takes 10% of paid subscriber revenue. built-in discovery and recommendation network. Plunk's biggest strengths are: open source and transparent. open-source codebase gives you full transparency and community-driven development.

Watch out for: With Substack, users commonly note that 10% revenue cut is steep at scale. With Plunk, the main complaint is that may lack some advanced features.

Choose Substack if...

You need a tool built for writers who want to monetize with paid subscriptions
You specifically need Community and Discovery Network
You care about built-in discovery and recommendation network
Your team size fits the individuals profile Substack is designed for

Choose Plunk if...

Your profile matches its sweet spot: developers wanting open-source transactional email
You need self-hosting, data sovereignty, or the ability to audit source code
You specifically need Analytics and Automations
You care about open-source codebase gives you full transparency and community-driven development
Your team size fits the small teams profile Plunk is designed for