Most newsletter platform comparisons focus on pricing, templates, and user interface design.
That is useful when the goal is simply to publish a weekly email. But if you are building a paid newsletter, a media business, or a content engine connected to other applications, the technical layer matters just as much.
APIs, webhooks, DNS configuration, template control, data portability, and payment ownership determine how far a platform can grow before it becomes a constraint.
This comparison examines six newsletter platforms:
Beehiiv
Kit
Mailchimp
Substack
Ghost
MailerLite
Here is what developers should evaluate before committing to one.
The stack underneath: what you are actually renting
Every newsletter platform is an abstraction built on top of several technical layers.
Email delivery
This includes:
sending infrastructure;
SMTP relays;
IP reputation;
bounce handling;
suppression lists;
complaint processing.
It directly affects deliverability.
Subscriber management
This layer stores:
email addresses;
custom fields;
tags;
segments;
consent information;
subscription status.
Its flexibility determines how easily subscribers can be queried, synchronized, and moved between systems.
Content engine
The content engine manages:
writing;
templates;
scheduling;
RSS feeds;
archives;
publication workflows.
It determines how much of the editorial process can be automated.
Public website
Most modern newsletter platforms also provide:
a hosted website;
public post archives;
landing pages;
subscription forms;
SEO settings.
This layer affects organic discovery and the amount of traffic a newsletter can attract outside the inbox.
Monetization
Monetization can include:
paid subscriptions;
digital products;
advertising;
sponsorships;
recommendation programs;
payment processing.
The key question is not only whether monetization exists, but who controls the customer and payment relationship.
Developer surface
The developer surface includes:
REST APIs;
webhooks;
SDKs;
authentication;
integration keys;
automation endpoints.
This determines how easily the platform can become part of a wider technical stack.
Most newsletter services bundle all these layers together.
The real question is how much control they provide before the platform becomes a limitation.
API quality: the real differentiator
For developers, the API is the escape hatch.
It determines whether you can:
synchronize subscribers with an external database;
trigger automations from product events;
connect a CRM;
build custom dashboards;
import or export subscriber data;
create internal publishing tools;
automate segmentation;
migrate away later.
Beehiiv
Beehiiv provides a REST API with useful coverage across:
publications;
subscribers;
subscriptions;
segments;
custom fields;
automations;
webhooks.
Authentication is handled through API keys associated with a publication.
Its documentation is clear and continues to improve. For most newsletter businesses, the API covers the essential workflows.
Programmatic post creation is more restricted than subscriber management and is tied to Beehiiv’s enterprise-oriented Send API.
Beehiiv therefore offers a solid developer surface, but not the same level of publishing control as Ghost.
Kit
Kit provides a mature REST API and webhook system.
It is particularly well suited to:
subscriber management;
forms;
tags;
purchases;
creator automations;
integrations with external products.
The documentation is strong, and the API fits naturally into creator-focused workflows.
Kit offers one of the best overall developer experiences in this comparison.
Mailchimp
Mailchimp has one of the broadest API surfaces.
It supports:
API keys;
OAuth 2.0;
audience management;
campaigns;
templates;
automations;
reports;
e-commerce integrations.
Its main advantage is depth.
Its main disadvantage is complexity.
Mailchimp has accumulated many products and workflows over the years, so its API can feel heavier than those of newer platforms.
Substack
Substack does not provide a broadly documented public API for the subscriber-management and automation workflows developers typically expect.
That limits the ability to:
synchronize subscribers programmatically;
trigger custom automations;
build internal dashboards;
connect application events;
create deeply customized workflows.
Substack remains easy to use as a publishing product, but it is less suitable when the newsletter needs to become part of a larger technical system.
Ghost
Ghost provides both a Content API and an Admin API.
Authentication uses integration keys and JWT-based mechanisms, depending on the API and operation.
Ghost stands out because it is:
open source;
self-hostable;
highly customizable;
well documented;
suitable for custom publishing applications.
Its API is one of the strongest options for teams that want direct control over content, members, themes, and publication infrastructure.
MailerLite
MailerLite provides a REST API with token-based authentication.
It covers the main workflows required by a newsletter application:
subscriber management;
groups;
campaigns;
forms;
automations;
webhooks.
It is less extensive than Mailchimp or Ghost, but it provides the essentials without the same level of complexity.
Custom domains and DNS: separate the different layers
“Custom domain support” is often presented as a single feature.
In practice, several different domain-related capabilities need to be evaluated separately:
public website domain;
visible sender address;
sending domain;
DKIM authentication;
SPF alignment;
DMARC policy;
tracking domain;
return-path domain.
A platform may allow a custom website domain without providing the same level of control over email delivery.
For a serious newsletter operation, the ideal setup includes:
a sender address using your own domain;
DKIM signing;
SPF alignment;
an appropriate DMARC policy;
a custom tracking domain when available;
clear DNS verification instructions.
Beehiiv
Beehiiv provides a guided domain setup.
The platform displays the required DNS records, which are then added through the domain provider and verified inside Beehiiv.
The process is relatively straightforward, although website domains, sending authentication, and tracking configuration should still be treated as separate settings.
Kit
Kit also offers a guided authentication process.
It is generally easy to configure for creators who already control their domain, and the documentation explains the required DNS records clearly.
Ghost
Ghost offers extensive control, particularly when self-hosted.
The trade-off is that additional flexibility can require more configuration and infrastructure knowledge.
Teams using Ghost need to understand which email provider is responsible for delivery and how sender authentication is configured.
Mailchimp
Mailchimp supports domain authentication and the necessary DNS configuration.
The setup can feel more complex because Mailchimp supports many account types, products, and legacy configurations.
Substack
Substack supports custom domains for the publication’s public web presence.
That should not be confused with complete control over the underlying email-delivery infrastructure.
MailerLite
MailerLite supports sender-domain authentication and provides DNS instructions inside the platform.
As with the other services, website-domain support and sending-domain authentication should be evaluated separately.
Webhooks: the difference between a tool and a platform
A webhook turns a newsletter platform from an isolated application into a component of a larger system.
Examples include:
new subscriber → send a Slack notification;
paid subscription → grant access inside an application;
failed payment → update the CRM;
unsubscribe → revoke a permission;
published article → trigger a static-site rebuild;
tag change → start an external workflow.
Beehiiv
Beehiiv supports webhook events related to subscribers, subscriptions, publications, and other account activity.
Before using them in production, verify:
the current authentication mechanism;
retry behavior;
event identifiers;
payload structure;
plan requirements.
Kit
Kit provides webhooks for creator-oriented events such as:
subscribers;
purchases;
forms;
tags.
It integrates well with automation workflows, although the current verification and retry behavior should be confirmed before deployment.
Mailchimp
Mailchimp provides webhook support across audiences, campaigns, and account events.
Its broader ecosystem makes it useful for complex marketing stacks.
As with any webhook integration, payload verification and deduplication should be implemented before processing events.
Substack
Substack does not provide a broadly documented webhook system for external developer workflows.
This makes event-driven integrations more difficult.
Ghost
Ghost supports native webhooks for events involving:
posts;
pages;
members;
subscriptions.
A webhook secret can also be configured.
Ghost is particularly useful when publishing events need to trigger processes elsewhere in the stack.
MailerLite
MailerLite supports webhook events for subscribers, campaigns, and automations.
It documents HMAC SHA-256 signatures, allowing incoming payloads to be authenticated.
What a production webhook implementation should verify
The number of available events is not enough.
A production-ready implementation should answer these questions:
Can the payload be authenticated?
Are failed deliveries retried?
Is there a unique event identifier?
Can duplicate events be detected?
Is event ordering guaranteed?
Can webhook delivery attempts be inspected?
Can secrets be rotated safely?
Webhook handlers should also be idempotent.
Receiving the same event twice should not create two accounts, process two payments, or grant the same permission twice.
Incoming payloads should never be trusted without validation.
Template customization: HTML access is not binary
Every newsletter platform provides an editor.
The important question is how much control exists underneath it.
There is a major difference between:
inserting an HTML block;
modifying a public website;
controlling the full email markup;
writing custom CSS;
creating reusable templates;
building an entire theme.
Beehiiv
Beehiiv provides a visual editor and website customization.
Custom HTML is available in certain workflows, but it should not be considered equivalent to unrestricted control over the full email markup.
It offers enough flexibility for many newsletter businesses without requiring developers to maintain a complete theme system.
Kit
Kit provides both visual editing and HTML customization.
It offers a useful balance between ease of use and template control.
Developers can customize email layouts without building an entire publishing system from scratch.
Mailchimp
Mailchimp provides extensive template control.
It supports:
visual editing;
raw HTML templates;
custom CSS;
reusable components;
a large template ecosystem.
It remains a strong choice when granular control over email design is required.
Substack
Substack deliberately prioritizes simplicity.
Its editor is easy to use, but HTML and CSS access are limited.
That is suitable for writers who do not want to manage templates, but restrictive for teams requiring custom layouts or embedded components.
Ghost
Ghost offers the deepest customization in this comparison.
Its Handlebars theme system can control the publication’s public front end.
That makes Ghost highly flexible, but it also introduces more development and maintenance work.
MailerLite
MailerLite supports visual editing, HTML access, and basic template customization.
It covers common newsletter workflows without providing the same theme-level control as Ghost.
Data portability: the lock-in test
The best platform is not only the one that works today.
It is also the one you can leave later.
Before committing, determine whether you can retrieve:
subscriber email addresses;
custom fields;
tags;
segments;
consent records;
content archives;
media files;
automation configurations;
payment records;
active subscription relationships.
Beehiiv
Beehiiv supports subscriber exports and provides ways to access publication data.
Its migration options are sufficient for many newsletter businesses, although the overall export model is less comprehensive than Ghost’s structured JSON approach.
The payment setup is Stripe-based, but payment portability should be examined separately from subscriber portability.
Kit
Kit supports CSV subscriber exports and provides options for accessing creator and subscriber data.
Its ecosystem is designed around creator workflows, and the platform offers reasonable portability for lists, tags, and customer information.
Mailchimp
Mailchimp supports exporting:
contacts;
audience data;
reports;
campaign information;
templates in certain workflows.
Its broad feature set means a full migration can still require significant work.
Substack
Substack allows subscriber exports.
However, moving the complete publication can be more complicated when it includes:
archives;
formatting;
comments;
recommendations;
community interactions;
paid subscriptions;
payment history.
The subscriber list may be portable while the surrounding ecosystem is not.
Ghost
Ghost offers the strongest portability model.
It supports structured JSON and CSV exports and can be self-hosted.
Publishers can also connect their own Stripe account, giving them more direct control over the payment relationship.
Ghost is the least restrictive choice for teams that want the option to move infrastructure later.
MailerLite
MailerLite supports subscriber exports and provides campaign and account export options.
It offers reasonable portability for standard newsletter operations.
Payment portability deserves separate attention
“Stripe integration” does not automatically mean that subscriptions can be migrated seamlessly.
Before launching a paid newsletter, determine:
who owns the Stripe account;
who owns the customer objects;
whether recurring subscriptions can be migrated;
whether payment history can be exported;
what happens to active subscriptions after cancellation;
whether subscribers need to enter payment details again after migration.
Moving an email list is relatively straightforward.
Moving a recurring payment relationship can be much more difficult.
Deliverability: what matters and what does not
Every newsletter platform claims strong deliverability.
The underlying reality is more complicated.
Shared sending infrastructure
Most newsletters are sent through infrastructure shared with other customers.
The platform manages:
sending IPs;
reputation monitoring;
suppression lists;
abuse detection;
bounce handling;
complaint processing.
Users generally do not choose their IP pool directly.
The important question is how effectively the provider identifies problematic senders and isolates abusive traffic.
Bounce handling
A platform should distinguish between:
hard bounces;
soft bounces;
blocked messages;
spam complaints;
invalid addresses;
suppressed contacts.
Hard bounces should normally be suppressed automatically.
Temporary failures may be retried depending on the provider and the receiving mail server.
The main difference between platforms is often visibility. Some expose detailed bounce events and suppression data, while others keep most of that information internal.
Authentication and compliance
A serious email setup should include:
DKIM;
SPF alignment;
DMARC;
one-click unsubscribe;
a valid physical address when legally required;
a clear sender identity.
The platform should make these elements easy to configure, but the publisher remains responsible for legitimate sending practices.
Domain warm-up
Moving to a new domain or sending infrastructure can affect sender reputation.
A new sender should avoid delivering a very large campaign immediately.
Volume should increase progressively while monitoring:
bounce rates;
complaint rates;
inbox placement;
open rates;
click rates.
Shared infrastructure can reduce some operational complexity, but it does not remove the importance of list quality.
Engagement matters more than marketing claims
The biggest deliverability factor is usually not the platform logo.
It is the quality of the audience and the sender’s behavior:
how subscribers were acquired;
whether they actively consented;
how often inactive users are removed;
bounce rates;
complaint rates;
sending consistency;
open and click engagement.
A well-maintained and engaged list on a basic platform can outperform a neglected list on an expensive one.
What I would choose — and why
There is no universally best newsletter platform.
The right choice depends on which technical constraint matters most.
Best API and developer experience: Kit or Ghost
Kit provides a mature API and strong support for creator workflows.
Ghost offers broad control through its Content and Admin APIs, especially for custom publishing systems.
Best data portability: Ghost
Ghost’s open-source model, structured exports, self-hosting option, and user-controlled Stripe integration make it the least restrictive platform in this comparison.
Best balance between power and simplicity: Beehiiv
Beehiiv combines:
an accessible interface;
APIs;
webhooks;
website publishing;
monetization;
audience-growth features.
It does not provide Ghost-level infrastructure control, but it requires significantly less implementation work.
Best for complex marketing operations: Mailchimp
Mailchimp remains relevant when a project needs:
a large integration ecosystem;
complex marketing workflows;
detailed campaign reporting;
broad API coverage;
e-commerce integrations.
The trade-off is additional complexity.
Simplest publishing experience: Substack
Substack is fast to start and removes most technical configuration.
That simplicity comes at the cost of API access, customization, and integration flexibility.
Lowest-cost starting point: Beehiiv or Substack
Beehiiv offers a free plan for up to 2,500 subscribers.
Substack has no fixed software cost for a basic publication.
The better option depends on whether the priority is integrated growth tooling or minimal financial commitment.
For a broader comparison covering pricing, AI features, monetization, SEO, and practical limitations, this detailed Beehiiv review in French provides a useful companion to the technical overview above.
Bottom line
Most newsletter platforms hide their technical limitations behind polished marketing pages.
Before committing, answer four questions:
Can every important dataset be exported?
Does the API support the workflows the product will require?
Can incoming webhook events be authenticated safely?
Is the template system flexible enough for future customization?
A platform does not need to provide unlimited control.
It needs to provide enough control for the system you are building.
The difficult part is predicting which limitations will matter six months or two years from now.
Migrating code is usually manageable.
Migrating an audience, its subscription history, its payment relationships, and its sender reputation is much harder.
