Customer.io vs Mailjet
Customer.io and Mailjet are both popular choices in the email marketing platform space. Mailjet starts at $9/mo versus $100/mo for Customer.io. Mailjet offers a free plan (6,000 emails/month (200/day), 1,000 contacts), while Customer.io does not. Mailjet has the edge with landing pages.
Quick Verdict
Customer.io wins on deliverability, rating, integrations.
Mailjet wins on price, free tier.
Best for most users: Customer.io (product led saas companies with event driven messaging needs).
Customer.io
Behavioral messaging platform for product-led SaaS and tech companies
Customer.io is a behavioral messaging platform built for product-led SaaS companies that need to trigger automated emails, SMS, push notifications, and in-app messages based on real-time user events. Its visual workflow builder and Liquid templating provide deep personalization, while the built-in Data Pipelines act as a lightweight CDP. Trusted by 8,000+ companies including Notion and Segment, it starts at $100/month for 5,000 profiles.
Mailjet
Collaborative email platform for teams with powerful API
Mailjet is a French-founded email platform (now owned by Sinch) that uniquely combines transactional and marketing email under one roof with real-time team collaboration. Its volume-based pricing with unlimited contacts makes it particularly cost-effective for businesses with large subscriber lists but moderate sending frequency. With strong GDPR compliance baked into its European DNA and a flexible API, it bridges the gap between developer-focused tools and marketer-friendly platforms.
Feature Comparison
| Feature | Customer.io | Mailjet |
|---|---|---|
| Rating | 4.4/5 | 4/5 |
| Starting Price | $100/mo | $9/mo |
| Free Plan | No free plan | 6,000 emails/month (200/day), 1,000 contacts |
| Founded | 2012 | 2010 |
| Email Templates | 30 | 70 |
| Integrations | 150 | 110 |
| Deliverability Rate | 96% | 88% |
| Marketing Automation | ✓ | ✓ |
| A/B Testing | ✓ | ✓ |
| Landing Pages | ✕ | ✓ |
| Segmentation | ✓ | ✓ |
| Drag & Drop Editor | ✓ | ✓ |
| SMS Marketing | ✓ | ✓ |
| Ecommerce Features | ✕ | ✕ |
| API Access | ✓ | ✓ |
| Multi-Language | ✓ | ✓ |
| Web Push Notifications | ✓ | ✕ |
| Live Chat | ✕ | ✕ |
| Advanced Analytics | ✓ | ✓ |
Customer.io: Pros & Cons
Pros
- +Powerful visual workflow builder with real-time event-based triggers for behavioral automation
- +Omnichannel messaging across email, SMS, push notifications, in-app, and webhooks in one platform
- +Built-in Data Pipelines that serve as a lightweight CDP, unifying web, mobile, and backend data
- +Segment builder is intuitive enough for marketers without requiring dedicated engineering support
- +Startup Program offers up to 12 months free for qualifying early-stage companies
Cons
- −Essentials plan starts at $100/month for only 5,000 profiles — expensive for small teams
- −Steep learning curve for non-technical users, especially with Liquid templating syntax
- −Pricing scales aggressively past 10K profiles with significant jumps between plan tiers
- −Template editor feels restrictive for highly custom-coded email layouts
- −Searching for past messages and editing templates can be unintuitive and slow
Mailjet: Pros & Cons
Pros
- +Real-time collaborative email editing lets multiple team members work on the same campaign simultaneously with live comments
- +Volume-based pricing with unlimited contacts means large lists stay affordable — one user grew from 0 to 50,000 subscribers affordably
- +Strong GDPR compliance built into the platform with EU data hosting, as a French-founded company under European regulations
- +RESTful API with SMTP relay supports both transactional and marketing email from a single platform
- +Deliverability rated 88% by EmailToolTester (above 83.1% industry average) with built-in list validation powered by Mailgun
Cons
- −Automation builder covers basics but lacks depth — triggers based on opens/clicks are tricky to configure and abandoned cart requires Zapier
- −No built-in landing page builder, forcing users to rely on third-party tools for lead capture
- −Many of the 110 integrations route through Zapier rather than being native direct connections
- −Migration from other ESPs is largely manual with limited import assistance for contacts, templates, and automations
- −Customer support response times are frequently criticized, with some serious technical issues going unresolved for extended periods
The Verdict
Customer.io edges ahead with a 4.4/5 rating compared to Mailjet's 4/5. The gap comes mainly from deliverability (4.4 vs 3.5) and ease of use (4.7 vs 4.2). On deliverability, Customer.io reports 96% compared to 88% for Mailjet — a meaningful difference if inbox placement is critical for your campaigns.
| Criterion | Weight | Customer.io | Mailjet |
|---|---|---|---|
| Starting Price | 30% | $100/mo | $9/mo |
| Deliverability | 25% | 96% | 88% |
| Rating | 25% | 4.4/5 | 4/5 |
| Integrations | 10% | 150 | 110 |
| Free Tier | 10% | No | Yes |
Weights determine how much each criterion counts toward the final score. See full methodology
Choose Customer.io if…
- + You're a product led saas companies with event driven messaging needs
- + You're a technical marketing teams that want advanced automation with liquid logic
- + Powerful visual workflow builder with real-time event-based triggers for behavioral automation
Choose Mailjet if…
- + You want lower starting costs ($9/mo)
- + You need a free plan to get started
- + You need built-in landing pages
- + You're a marketing teams needing real time email collaboration