Plunk vs Postmark (2026): which should you pick?
As of Nov 13, 2026, Plunk grades higher than Postmark: 2.6 against 2.2 out of 4.0.
Checked Oct 18, 2026 and Nov 13, 2026 · graded Oct 18, 2026 and Nov 13, 2026 by ToolGPA
Plunk grades higher on value for money. They get the same grade on the free plan, features, ease of use and platforms.
Price, platforms and features side by side. The table says where each price was read and when.
Plunk
Open-source email platform for transactional and marketing mail
Postmark
Transactional email API and SMTP, with broadcasts on a separate stream
Which one is for you
Pick Plunk if
- Fits if you send a few thousand emails a month and want pay-as-you-go
- Works for developers who might self-host it later
Look elsewhere if
- Tight if you send more than 1,000 emails a month on the free plan, which also adds Plunk branding
- Pricey if your volume grows, since it is a flat $0.001 on every email
- Watch out: self-hosting under AGPL-3.0 carries that licence's obligations
- Watch out: the hosted service runs in the EU
Pick Postmark if
- Fits if you want password resets kept on a separate stream from your newsletters
- Works for apps that need to look back at exactly what an email said weeks later
Look elsewhere if
- Pricey if you send 50,000 emails a month, at $55 with no yearly discount
- Skip it if you want a free plan to run a small app on, as it's 100 emails a month with no tier until 10,000
- Tight if you're on Basic, with 4 users, 5 sending domains and no inbound email
- Not for you if you want a dedicated IP below 300,000 emails a month, and each one is $50 a month on Pro or higher
- Watch out: DMARC reports are an add-on from $14 a month per domain
How we grade them
| 2.6GPAPlunkGood | 2.2GPAPostmarkFair | |
|---|---|---|
| Value for money | BNo monthly fee; $0.001 per email, so 10,000 emails cost $10, near the cheapest quarter of $9 for sending tools. Cost grows with volume. | DGraded on 50,000 emails a month: $55 on Basic or $60.50 on Pro, billed monthly only. That's the dearest in this category at that volume, roughly twice the middle. Bootstrapped companies can ask for $75 of credit. |
| Free plan and trial | CFree for 1,000 emails a month with unlimited contacts and every feature, but emails carry Plunk branding. | CA free developer plan that never expires and needs no card, but it's 100 emails a month with no way to buy more. That's for testing an integration, not running an app. |
| Features | BTransactional email, campaigns, workflows, segments and inbound email. The listing shows no gap in the core job. | BAPI and SMTP with SDKs, separate streams for app and bulk email, inbound email turned into JSON, templates, 45 days of message history and DMARC reports as an add-on from $14 a month. It covers the job; inbound needs Pro. |
| Ease of use | CNo store rating on record. It is built for developers and can be self-hosted under AGPL-3.0. | CJudged on how fast a developer sends a first email: official SDKs, a sandbox mode, ready-made templates for resets and receipts, and migration guides. You'll still verify a domain first. No rating on record. |
| Platforms and integrations | BWeb, with Amazon SES and Docker listed. No apps, and the hosted service is in the EU. | BWeb, with an API and SMTP, plus Zapier, WordPress, Stripe, Slack, Supabase, Bubble, Netlify and Datadog. No desktop or phone app, so B is the top. |
| Best for | open-source email sending at $0.001 an email | app email kept apart from marketing sends |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: Plunk and Postmark. How we grade
Where they differ
- Plunk is open source and self-hostable, according to its own site.
- Plunk also covers workflow automation and email campaigns.
- Postmark also covers dMARC.
At a glance
| Plunk | Postmark | |
|---|---|---|
| Pricing | Free plan | Free plan |
| Starts at | $0.001 per email sent | $15 per month for 10,000 emails |
| Free plan | 1,000 emails per month with unlimited contacts and every feature, with Plunk branding on emails. | Free developer plan: 100 emails a month with no expiry and no overages, for testing an integration or a small side project. No credit card needed. |
| Free trial | None listed | None listed |
| Web | ||
| Made by | Plunk | ActiveCampaign, LLC |
| Price read from | useplunk.com | postmarkapp.com |
| Checked | Nov 13, 2026 | Oct 18, 2026 |
Worth knowing
Plunk
- The free plan stops at 1,000 emails a month and puts Plunk branding on emails.
- The paid plan has no monthly fee: it is $0.001 per email, so cost scales directly with volume.
- The hosted service is in the EU; self-hosting under AGPL-3.0 carries that license's obligations.
Postmark
- There is no tier between the free 100 emails a month and the 10,000-email paid plans.
- Billing is monthly only; the FAQ says annual plans are not offered yet.
- Basic has no inbound email processing and caps users at 4 and sending domains at 5.
- Dedicated IPs start at $50 a month per IP, need Pro or higher and 300,000 emails a month or more.
Key features
Plunk
- Transactional email
- Send single emails through a REST API or an SMTP relay, from your own domain with DKIM signing.
- Campaigns and newsletters
- Broadcasts go to the whole contact list or to a segment, with a visual and an HTML editor and open and click tracking.
- Workflows
- Event-triggered sequences with delays, conditions and webhook steps, started by something a contact does in your product.
- Segments
- Dynamic segments are queries that re-run each time they are used, so a campaign reaches the current audience.
- Inbound email
- Addresses at your domain can receive mail, and replies become contacts that can start workflows.
- Self-hosting
- The code is open source under AGPL-3.0 and can be deployed with Docker Compose on your own servers.
Postmark
- Email API and SMTP
- Send through a REST API with official SDKs or through SMTP, with batch sending, a sandbox mode and migration guides from other providers.
- Message streams
- Transactional and bulk or broadcast email run on separate sending infrastructure, so marketing sends do not affect password resets and receipts.
- Inbound email processing
- Pro and Platform turn incoming email into a JSON object and post it to a webhook URL your app handles.
- Templates
- Responsive templates for welcome emails, password resets and receipts, with a template editor and import tool.
- Message history and analytics
- 45 days of full message content by default, adjustable from 7 to 365 days, with bounce details, open and link tracking and a stats API.
- DMARC monitoring
- DMARC Digests reports show authentication problems and who is sending with your domain, sold as an add-on from $14 a month per domain.
Plans
Plunk
Free forever$0
1,000 emails a month and unlimited contacts. Every feature is included, but emails carry Plunk branding.
Pay as you grow$0.001
per email sent, no monthly fee
Removes the Plunk branding and the 1,000-email cap, with a monthly spend cap you can set. The vendor's example shows 10,000 emails costing $10.
Postmark
Free$0
100 emails a month, never expires; extra emails cannot be bought on this plan.
Basic$15
per month for 10,000 emails
5 sending domains, 4 users, 45 days of history, no inbound email. Extra emails $1.80 per 1,000; $55 a month at 50,000 emails.
Pro$16.50
per month for 10,000 emails
10 domains, 6 users, inbound email, retention up to 365 days. Extra emails $1.30 per 1,000; $60.50 a month at 50,000 emails.
Platform$18
per month for 10,000 emails
Unlimited domains, servers, streams and users, with inbound email. Extra emails $1.20 per 1,000; $66 a month at 50,000 emails.
High volumeCustom
Custom pricing for large senders, arranged through sales.
Ways to pay less
Plunk
No public discounts listed.
Postmark
- Startups
$75 credit for bootstrapped companies
Companies that have launched, are charging for their product and have taken no outside investment can ask support for $75 of account credit.
Common questions
Which is cheaper, Plunk or Postmark?
As of Nov 13, 2026, Plunk starts at $0.001 per email sent, and Postmark starts at $15 per month for 10,000 emails.
Which has a free plan, Plunk or Postmark?
As of Nov 13, 2026, both Plunk and Postmark have a free plan.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.