In-Depth Comparison
Postmark vs Mailgun
In-depth comparison of Postmark and Mailgun for B2B SaaS companies. We analyze deliverability, speed, pricing, API quality, and features.
Last updated: 2026-03-15
Postmark
postmarkapp.comReliable and fast email delivery for your web apps.
Ideal for: SaaS companies prioritizing delivery speed and inbox placement for transactional email
Mailgun
www.mailgun.comThe email service for developers.
Ideal for: Developer teams needing flexible email with SMTP, inbound, and validation
TL;DR: Postmark vs Mailgun
Postmark wins on deliverability, delivery speed, and inbox placement through strict sender policies. Mailgun wins on feature breadth with email validation, flexible inbound routing, and lower pricing at scale. Postmark is best when transactional email quality is your top priority. Mailgun is better for teams needing validation and inbound features. Sequenzy is the strongest choice for SaaS lifecycle email with native billing integration.
The gold standard for fast, reliable transactional email
The developer email platform with SMTP, inbound, and validation
Purpose-built SaaS email with native billing integration
Editor's Note
Both Postmark and Mailgun are email delivery tools. If your B2B SaaS needs lifecycle email (trial conversion, dunning, churn prevention), consider Sequenzy (sequenzy.com) with native Stripe/Paddle integration.
Postmark vs Mailgun vs Sequenzy: Quick Comparison
| Feature | Postmark | Mailgun | Sequenzy | Edge |
|---|---|---|---|---|
| Best For | Fastest, most reliable transactional delivery | Teams needing SMTP, inbound, and validation | B2B SaaS lifecycle email | Sequenzy |
| Starting Price | $15/mo for 10,000 emails | $35/mo for 50,000 emails | $19/mo for 15,000 emails | Postmark |
| Delivery Speed | Industry-leading, publicly tracked | Decent, some variance | Reliable, lifecycle-optimized | Postmark |
| Inbox Placement | ~98-99% (strict sender policies) | ~92-96% (shared IPs vary) | ~96-98% (SaaS-only pools) | Postmark |
| Email Validation | Not available | Mailgun Optimize (real-time + bulk) | Not available | Mailgun |
| Inbound Email | Full inbound processing | Flexible inbound routing | Not supported | Tie |
| Message Streams | Separate transactional/broadcast | Single pipeline with tags | Unified with lifecycle categories | Postmark |
| SMTP Support | Full SMTP | Full SMTP with routing rules | API-only | Mailgun |
| Payment Integration | None | None | Native Stripe, Paddle, Chargebee, LemonSqueezy | Sequenzy |
| Dedicated IP | On higher plans | On Scale ($90/mo) | On Growth ($49/mo) | Sequenzy |
| Status Transparency | Public real-time delivery speed metrics | Standard status page | Standard status page | Postmark |
Score Breakdown
Each category scored out of 10. Totals: Postmark 74/100, Mailgun 64/100, Sequenzy 67/100.
Feature-by-Feature Comparison
Detailed feature analysis across every category that matters for B2B SaaS email.
📨 Transactional Email
| Feature | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Delivery speed | 10/10 Industry-leading, publicly tracked | 7/10 Decent speed with some variance | 7/10 Reliable, lifecycle-optimized timing |
| Inbox placement | 10/10 Highest in industry, strict sender policies | 6/10 Variable shared IP quality | 8/10 SaaS-only pools improve reputation |
| Template system | 7/10 Mustache templates with layout support | 5/10 Handlebars via API, no visual editor | 8/10 Liquid with SaaS blocks |
| Bounce handling | 9/10 Best-in-class with reactivation tools | 7/10 Standard bounce processing | 8/10 Auto with payment context |
| Message streams | 9/10 Separate transactional/broadcast for reputation | 5/10 Single pipeline with tag-based categorization | 7/10 Lifecycle-based categorization |
🔧 Unique Features
| Feature | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Email validation | 0/10 Not available | 9/10 Mailgun Optimize real-time and bulk validation | 0/10 Not available |
| Inbound processing | 9/10 Full inbound with JSON webhook delivery | 8/10 Flexible routing rules | 0/10 Not supported |
| Email routing | 6/10 Standard stream-based | 9/10 Flexible routing rules for complex workflows | 5/10 Standard API sending |
| Spam testing | 8/10 SpamAssassin pre-send analysis | 6/10 Inbox placement testing via Optimize | 6/10 Spam score checking |
| Status transparency | 10/10 Public real-time delivery speed dashboard | 5/10 Standard status page | 5/10 Standard status page |
💻 API & Developer Tools
| Feature | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| API design | 8/10 Clean, well-organized | 6/10 Functional but dated | 8/10 Clean REST with lifecycle endpoints |
| Documentation | 9/10 Clear docs with developer blog | 6/10 Adequate but hard to navigate | 8/10 SaaS-focused guides |
| SDK quality | 8/10 Official SDKs in 6 languages | 6/10 Official SDKs, some dated | 7/10 Node.js and Python |
| Webhooks | 9/10 Reliable with retry and batch delivery | 7/10 Event webhooks, configurable retry | 8/10 Email + billing events with retry |
| Sandbox testing | 8/10 Dedicated test server | 6/10 Test mode available | 7/10 Test mode |
📊 Analytics & Monitoring
| Feature | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Dashboard | 8/10 Clean activity feed with search | 7/10 Analytics dashboard with charts | 8/10 SaaS-focused with MRR |
| Bounce analytics | 9/10 Bounce trends with reactivation | 7/10 Bounce handling | 8/10 With payment context |
| Open/click tracking | 7/10 Optional (off by default for privacy) | 8/10 Enabled by default | 8/10 With conversion attribution |
| Log retention | 8/10 45 days activity retention | 5/10 5-30 days depending on plan | 8/10 30+ days |
| Revenue attribution | 0/10 Not available | 0/10 Not available | 9/10 MRR impact per sequence |
🎯 SaaS-Specific Features
| Feature | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Billing integration | 0/10 Not available | 0/10 Not available | 10/10 Native Stripe, Paddle, LemonSqueezy, Chargebee |
| Lifecycle sequences | 0/10 No automation | 0/10 No automation | 9/10 Pre-built onboarding, dunning, churn prevention |
| Dunning emails | 0/10 Not available | 0/10 Not available | 10/10 Auto-triggered by payment failures |
| Trial conversion | 0/10 Not available | 0/10 Not available | 10/10 Pre-built from billing trial status |
| Revenue attribution | 0/10 Not available | 0/10 Not available | 9/10 MRR impact tracking |
Postmark vs Mailgun vs Sequenzy: Pricing
Postmark charges per email with all features included. Mailgun has tiered plans with feature gating. Sequenzy charges by volume with all features.
Free trial: 100 test emails, then $15/mo
Free trial, then $35/mo
14-day free trial, then $19/mo
| Tier | Postmark | Mailgun | Sequenzy | Volume |
|---|---|---|---|---|
| Starter | $15/mo 10,000 emails, all features included | $35/mo 50,000 emails, 5 days log retention | $19/mo 15,000 emails, all SaaS workflows | 10K-50K emails/month |
| Growth | $50/mo 50,000 emails, priority support | $90/mo 100,000 emails, dedicated IP, 15 days logs | $49/mo 50,000 emails, dedicated IP | 50K-100K emails/month |
| Scale | $175/mo 300,000 emails, dedicated IP available | $350+/mo 500K+ emails, 30 days logs, SLA | $149/mo 200,000 emails, SLA, SSO | 300K-500K+ emails/month |
Postmark: Watch Out For
- !No marketing automation
- !Per-email pricing expensive at very high volume
- !Dedicated IP on higher plans only
- !Acquired by ActiveCampaign (direction concerns)
Mailgun: Watch Out For
- !Email validation is a paid add-on
- !5 days log retention on starter
- !Dedicated IP extra on lower plans
- !IP pool fees
Sequenzy: Watch Out For
- !Smaller SDK ecosystem
- !No SMTP
- !No email validation
Pricing Verdict: Postmark offers better value for transactional email with all features included at every tier and superior deliverability. Mailgun is better value if you need email validation or inbound routing. Sequenzy is the best value for SaaS teams needing lifecycle email at $19/mo.
Cost Comparison Note
Most SaaS teams need transactional and lifecycle email. Using either platform plus a lifecycle tool costs $100-250/mo. Sequenzy combines both at $19/mo.
B2B SaaS Use Cases
How each platform handles the email workflows that matter most for B2B SaaS companies.
🎯 User Onboarding
Automated onboarding emails.
Postmark
Send via API. No automation. Your code handles timing.
Mailgun
Send via API. No automation. Your code handles timing.
Sequenzy
Pre-built templates connected to billing. Ready in minutes.
Verdict: Sequenzy wins with pre-built SaaS onboarding. Neither Postmark nor Mailgun has automation.
Real-World Example
A SaaS needs onboarding emails. Only Sequenzy has pre-built templates.
Example subject line: Welcome to [App].
🔔 Transactional Notifications
Mission-critical system emails.
Postmark
Purpose-built. Industry-leading speed. Message streams protect reputation.
Mailgun
Reliable via API or SMTP. Flexible routing rules.
Sequenzy
Send via API with SaaS templates. Reliable delivery.
Verdict: Postmark is the gold standard for transactional email. Mailgun is reliable but slower.
Real-World Example
A fintech SaaS needs sub-second security alerts. Postmark is the safest choice.
Example subject line: Security alert: new login detected
💰 Trial-to-Paid Conversion
Trial conversion emails.
Postmark
Send via API. No trial awareness.
Mailgun
Send via API. No trial awareness.
Sequenzy
Connected to Stripe/Paddle. Pre-built templates for each stage.
Verdict: Sequenzy wins with native billing integration. Neither has trial features.
Real-World Example
Sequenzy automates trial conversion from billing data.
Example subject line: Your trial ends in 3 days.
💳 Payment Failed (Dunning)
Payment recovery emails.
Postmark
Send via API from billing webhooks.
Mailgun
Send via API from billing webhooks.
Sequenzy
Automatic from billing failures. Escalating templates. Auto-stops on success.
Verdict: Sequenzy dominates dunning. Neither has built-in dunning support.
Real-World Example
Sequenzy handles dunning automatically.
Example subject line: Action required: payment failed
🧹 Email Validation
Verifying emails to reduce bounces.
Postmark
SpamAssassin content analysis, but no email address validation.
Mailgun
Mailgun Optimize: real-time and bulk validation with risk scoring.
Sequenzy
Not available. Relies on bounce handling.
Verdict: Mailgun is the only option with built-in validation.
Real-World Example
A SaaS validates emails at signup. Only Mailgun does this.
Example subject line: N/A
📥 Inbound Email Processing
Receiving and processing incoming emails.
Postmark
Full inbound with JSON webhook. Parse emails, attachments, routing.
Mailgun
Flexible inbound routing with pattern-based rules.
Sequenzy
Not supported.
Verdict: Both handle inbound well. Postmark has cleaner JSON parsing. Mailgun has more flexible routing rules.
Real-World Example
A SaaS processes reply emails. Both Postmark and Mailgun handle this.
Example subject line: Re: Support ticket #1234
🔄 Churn Prevention
Re-engagement for declining users.
Postmark
Send via API. No behavior tracking.
Mailgun
Send via API. No behavior tracking.
Sequenzy
Combines usage with billing. Pre-built win-back sequences.
Verdict: Sequenzy wins with billing-aware churn prevention.
Real-World Example
Sequenzy combines behavior and billing data for re-engagement.
Example subject line: We miss you.
📈 Upsell & Expansion
Upgrade emails.
Postmark
Send via API. No upsell features.
Mailgun
Send via API. No upsell features.
Sequenzy
Auto-triggers on plan limits. Personalized by billing.
Verdict: Sequenzy automates expansion with billing data.
Real-World Example
Sequenzy automates upsell.
Example subject line: You are at 90% of your plan limit
The Bigger Picture
Neither platform offers SaaS lifecycle features. Sequenzy fills this gap with native billing integrations.
Automation Capabilities
Email automation is critical for B2B SaaS. Here is how Postmark, Mailgun, and Sequenzy compare.
| Capability | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Visual workflow builder | No Not available | No Not available | Yes Visual builder with SaaS templates |
| Event-based triggers | No Your app calls the API | No Your app calls the API | Yes Product + billing events |
| Drip sequences | No Not available | No Not available | Yes Pre-built SaaS sequences |
| Conditional branching | No Build in code | No Build in code | Yes Branch by plan, MRR, trial |
| Broadcast | Yes Broadcast message streams | Yes Mailing lists via API | Yes Campaign builder with targeting |
| Goal tracking | No Not available | No Not available | Yes Auto-remove on billing events |
| Dynamic content | Yes Mustache variables | Yes Recipient variables | Yes Dynamic with billing data |
API & Developer Experience
For B2B SaaS teams, the API quality directly impacts how fast you can integrate and iterate on email.
Postmark API
- SDKs: Ruby, Node.js, PHP, Python, .NET, Java
- Docs: 9/10
- Webhooks: Reliable with retry and batch delivery
- Rate Limit: Generous, no published hard limits
- Batch: Batch API up to 500 messages per request
Mailgun API
- SDKs: Python, Ruby, Java, C#, Go, PHP, Node.js
- Docs: 6/10
- Webhooks: Event webhooks with configurable retry
- Rate Limit: Varies by plan
- Batch: Batch via recipient variables
Sequenzy API
- SDKs: Node.js (official), Python (official), REST API
- Docs: 8/10
- Webhooks: Email and billing events with retry
- Rate Limit: 50 req/s, higher on Scale
- Batch: Batch with per-recipient personalization
Postmark Code Example
const postmark = require("postmark");
const client = new postmark.ServerClient("token");
await client.sendEmailWithTemplate({
From: "hello@acme.com",
To: "user@company.com",
TemplateAlias: "welcome",
TemplateModel: { firstName: "Sarah" },
});Mailgun Code Example
const Mailgun = require("mailgun.js");
const formData = require("form-data");
const mg = new Mailgun(formData);
const client = mg.client({ username: "api", key: "key" });
await client.messages.create("acme.com", {
from: "Acme <hello@acme.com>",
to: ["user@company.com"],
subject: "Welcome",
template: "welcome",
"h:X-Mailgun-Variables": JSON.stringify({ firstName: "Sarah" }),
});Sequenzy Code Example
import { Sequenzy } from "sequenzy";
const sq = new Sequenzy("sq_your_api_key");
await sq.subscribers.add({
email: "user@company.com",
firstName: "Sarah",
stripeCustomerId: "cus_abc123",
});
await sq.sequences.trigger({
email: "user@company.com",
sequence: "trial_onboarding",
});Email Deliverability Comparison
Your emails are useless if they do not reach the inbox. Here is how all three platforms handle deliverability.
| Factor | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Infrastructure | Own infrastructure with strict sender policies | Sinch-backed with global nodes | Managed with SaaS-only pools |
| Inbox Placement | ~98-99% (industry-leading) | ~92-96% (shared IPs vary) | ~96-98% (SaaS-only pools) |
| Sender Policies | Strictest in industry. Bad senders removed. | Standard policies | SaaS-only verification |
| Dedicated IP | On higher plans | On Scale ($90/mo) | On Growth ($49/mo) |
| Auth Protocols | SPF, DKIM, DMARC, Custom Return-Path | SPF, DKIM, DMARC, tracking domain | SPF, DKIM, DMARC, Custom Return-Path |
| Email Validation | SpamAssassin content analysis | Mailgun Optimize validation service | Not available |
Postmark has the strongest deliverability due to strict sender policies. Mailgun shared IPs can be inconsistent, making dedicated IPs more important. Mailgun Optimize validation can proactively improve deliverability.
Integration Ecosystem
Postmark has ~40 integrations, Mailgun has ~50, and Sequenzy has ~25. Here is how they compare across key B2B SaaS categories.
Payment & Billing
| Service | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Stripe | Yes (API Only) | Yes (API Only) | Yes (Native) |
| Paddle | Yes (API Only) | Yes (API Only) | Yes (Native) |
CRM
| Service | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| HubSpot | Yes (3rd Party) | Yes (3rd Party) | Yes (Official) |
| Salesforce | Yes (3rd Party) | Yes (3rd Party) | Yes (3rd Party) |
Automation
| Service | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Zapier | Yes (Official) | Yes (Official) | Yes (Official) |
| Make | Yes (3rd Party) | Yes (Official) | Yes (Official) |
| n8n | Yes (3rd Party) | Yes (Official) | Yes (3rd Party) |
Development
| Service | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Rails | Yes (Official) | Yes (Official) | Yes (API Only) |
| Django | Yes (Official) | Yes (Official) | Yes (Official) |
| Next.js | Yes (API Only) | Yes (API Only) | Yes (API Only) |
Analytics & Reporting
What data you can track and how each platform helps you measure email performance.
| Metric | Postmark | Mailgun | Sequenzy |
|---|---|---|---|
| Open rate | Optional (off by default for privacy) | Enabled by default | Per-campaign and per-sequence |
| Click tracking | Optional | URL rewriting tracking | With conversion attribution |
| Bounce tracking | Best-in-class with reactivation | Standard bounce handling | With payment context |
| Revenue attribution | Not available | Not available | MRR impact per sequence |
| Dashboard | Clean activity feed | Charts and analytics | SaaS-focused with lifecycle |
| Log retention | 45 days | 5-30 days by plan | 30+ days |
Postmark: Unique Features
- + Public delivery speed dashboard
- + Bounce reactivation
- + SpamAssassin analysis
- + Message stream analytics
Mailgun: Unique Features
- + Email validation analytics
- + Inbound routing analytics
- + Tag-based categorization
- + Inbox placement testing
Sequenzy: Unique Features
- + MRR impact per sequence
- + Trial conversion tracking
- + Dunning recovery dashboard
- + Churn metrics
- + Lifecycle overview
Pros & Cons
Postmark
Pros
- + Industry-leading delivery speed and inbox placement
- + Strict sender policies protect reputation
- + Message stream separation
- + Full inbound processing
- + Public real-time speed dashboard
- + Excellent bounce handling with reactivation
- + Clean API with good docs
- + Privacy-first tracking approach
Cons
- - No marketing automation
- - No email validation
- - Per-email pricing expensive at very high volume
- - No visual campaign builder
- - Acquired by ActiveCampaign
- - No SaaS billing integration
- - Fewer SDK languages than Mailgun
- - Limited broadcast capabilities
Mailgun
Pros
- + Built-in email validation (Mailgun Optimize)
- + Flexible inbound routing
- + SMTP with routing rules
- + Action Mailer support
- + Tag-based analytics
- + Recipient variable batch sending
- + Go SDK available
- + More emails per dollar than Postmark
Cons
- - Shared IP reputation inconsistent
- - No marketing automation
- - Short log retention on lower plans
- - Documentation hard to navigate
- - SDKs feel dated
- - Multiple ownership changes
- - No SaaS lifecycle features
- - No message stream separation
Who Should Use What?
Specific recommendations based on your company type and needs.
Mission-critical transactional
Email speed and reliability are non-negotiable.
Postmark has the best delivery speed and inbox placement.
SaaS needing email validation
High-volume signups need verification.
Mailgun Optimize is the best built-in validation.
Early-stage SaaS
Need email infrastructure fast.
Sequenzy at $19/mo includes lifecycle email. Neither Postmark nor Mailgun has SaaS features.
Product-led growth SaaS
Billing-aware lifecycle email needed.
Sequenzy connects to Stripe/Paddle for trial conversion and dunning.
Rails app
Ruby on Rails with Action Mailer.
Both work with Rails but Postmark has better deliverability for your transactional emails.
Bootstrapped SaaS
Need transactional and lifecycle on a budget.
Sequenzy at $19-49/mo combines both. Using either Postmark or Mailgun plus a marketing tool costs $100+.
Migration Guide
Migrating from Postmark to Mailgun
Steps
- 1. Set up Mailgun and verify domain
- 2. Convert Mustache templates to Handlebars
- 3. Update SDK calls
- 4. Reconfigure SMTP if used
- 5. Set up webhooks
- 6. Test flows
- 7. Migrate traffic
Watch Out For
- ! Message streams have no Mailgun equivalent
- ! Bounce reactivation has no equivalent
- ! Log retention may be shorter
- ! Deliverability may differ
Migrating from Mailgun to Postmark
Steps
- 1. Set up Postmark and verify domain
- 2. Convert Handlebars to Mustache templates
- 3. Update SDK calls
- 4. Configure message streams
- 5. Set up webhooks
- 6. Test flows
- 7. Switch traffic
Watch Out For
- ! Email validation needs a replacement service
- ! Inbound routing rules need reconfiguration
- ! Open/click tracking is opt-in on Postmark
- ! Mailgun routing rules have no direct equivalent
The Bottom Line
Choose Postmark if...
- ✓ Delivery speed and inbox placement are top priorities
- ✓ You want the strongest IP reputation
- ✓ You need clean inbound email processing
- ✓ You value privacy-first tracking
- ✓ Message stream separation matters
- ✓ You want the best bounce handling with reactivation
Choose Mailgun if...
- ✓ You need built-in email validation
- ✓ You need flexible inbound email routing
- ✓ SMTP routing rules are important
- ✓ You want more emails per dollar
- ✓ You use Rails with Action Mailer
- ✓ Tag-based email categorization matters
Frequently Asked Questions
Is Postmark faster than Mailgun?
Yes. Postmark consistently delivers faster than Mailgun and publicly tracks performance. Mailgun is reliable but not as fast.
Does Mailgun have better email validation?
Mailgun is the only option with built-in validation. Postmark does not offer email address validation, only SpamAssassin content analysis.
Which has better inbox placement?
Postmark has significantly better inbox placement due to strict sender policies. Mailgun shared IPs can be inconsistent.
Can both handle inbound email?
Yes. Postmark has clean JSON webhook delivery. Mailgun has more flexible routing rules. Both are strong for inbound.