Mailjet Review 2026: It Wrote MJML, and Scores Lowest Here

TL;DR, Should you still use Mailjet in 2026?

Mailjet gave the email industry something no competitor on this site has: MJML, the open-source markup language it released in 2016 and that email developers now use everywhere, including inside products that compete with it. It also ships a real SMTP relay, a well-documented REST API, and French data centres that matter to EU buyers. That is a serious engineering record.

And it carries the lowest scores in our entire set. G2 puts it at 3.9/5, below every other platform we have profiled. Capterra scores its customer service at 3.9, also the lowest we have recorded anywhere.

The corpus explains why, and the explanation is the same sentence over and over. Roughly 14 of the 74 distinct reviews we read describe an account blocked or suspended, frequently without warning: “account blocked without warning, very risky,” “account suspended without notice,” “security blocks never explained,” “block accounts without intimation.” That is 19 percent of the corpus, and several of them are four and five-star reviews.

The context you need before evaluating Mailjet in 2026

Mailjet was the first company launched by the Paris startup studio eFounders, registered there in August 2010 by Wilfried Durand and Julien Tartarin. Mailgun bought it in October 2019, and Sinch closed its $1.9 billion purchase of the combined Pathwire group on 7 December 2021. The French entity still files its own accounts, and the product is still sold alongside Mailgun rather than folded into it.

The contribution that matters most is not a feature. In 2016 Mailjet released MJML as open source: a markup language that compiles to responsive email HTML and spares developers the table-based nightmare that email templating had been for twenty years. It is now used across the industry, in tools that compete directly with Mailjet, by people who have never had a Mailjet account. Mailjet solved a category-wide problem and gave the solution away. Almost nothing else in this comparison group has done anything comparable.

Three commercial facts to carry in before you price it. The free plan gives 6,000 emails a month, but it is capped at 200 a day, so it cannot absorb a launch. The Mailjet logo stays on your emails until the Essential tier. And automations are Premium-only, which is two tiers up. Three separate gates, each of which a buyer typically discovers after signing up. Our pricing tab has the ladder.

One genuine differentiator for European buyers: French company, French data centres, GDPR posture. A reviewer lists exactly that as their reason for choosing it. In a category dominated by US platforms, that is a real procurement argument, and it is why Mailjet still wins tenders it might otherwise lose.

Snapshot

What Mailjet does well

It wrote MJML, and gave it to everyone

Released as open source in 2016, MJML compiles a clean semantic syntax down to the nested-table HTML that email clients still demand. It removed a genuine, decades-old tax on every developer who has ever built a responsive email. It is used inside products that compete with Mailjet, and by teams who will never be Mailjet customers.

We flag this because a review that only counted features would miss it entirely, and because it changes how you should read the rest of this page. This is not a company that cannot build. Whatever is going wrong here is not engineering.

The developer surface is genuinely good, and the corpus says so

A REST API that reviewers praise unprompted, even inside negative reviews: one 1-star review lists “API has good documentation” as its only Pro. Others name “good deliverability, okay API,” “the API access and the visual email” builder. Add a real SMTP relay, which only Mailjet, Brevo and Moosend publish in this group, and the technical story is strong.

Collaborative editing is a real feature, not a checkbox

Multiple people editing the same email at once, with comments, which is the workflow every agency and in-house team actually has and almost no competitor supports properly. Reviewers name it: “clean, simple interface for non-tech users, shared” editing, “this software is strongly designed for team collaboration.” If two people build your campaigns, this is a daily saving.

French hosting and a French legal entity

For an EU buyer with a procurement checklist, “data centers in France, French company, GDPR” is not marketing, it is the reason the tender is winnable. Most of this comparison group is US-domiciled. Mailjet is one of the few genuinely European options with a real transactional product behind it, and Sinch ownership has not changed the French filing entity.

The free tier is generous by volume, if not by shape

6,000 emails a month with unlimited contacts, which is more monthly volume than MailerLite’s 2,500 and far more than Klaviyo’s 500. Reviewers in French and Spanish single it out: “simple, gratuit et intuitif,” “su capa gratuita es excelente para iniciar.” The daily cap is the catch, and it is in the next section.

Where Mailjet falls short

One review in five describes an account blocked or suspended

This is the finding, and it is the reason this profile scores where it does. Roughly 14 of 74 distinct excerpts, about 19 percent, describe account blocking, suspension or compliance enforcement. The wording is consistent across five years and several languages:

• “Account blocked without warning, very risky” – one star, March 2026
• “Lack of reliability, accounts blocked without warning” – four stars, March 2026
• “Buggy UI, account suspended without notice” – three stars, March 2025
• “They suspended our account… prior notice” – one star, March 2025
• “Security blocks never explained, account blocked” – four stars, October 2018
• “Block accounts without intimation, pricing high” – five stars, July 2022
• “Early accounts suspended, emails bounced” – five stars, May 2020
• “Their TOS and enforcement of it is absolutely” – one star, September 2019
• “Frustrating compliance process and sending limits” – one star, June 2026

Read the star ratings. Four and five-star customers are describing being cut off. As with Brevo, where we measured 17 of 157, that combination is what turns a support anecdote into a product characteristic. The difference is the rate: Brevo ran at 11 percent, Mailjet at 19. And unlike Brevo, where the friction clustered in the first days and usually resolved, several of these describe established accounts stopped mid-flight.

The charitable reading is the same one that applies to Brevo: a platform with a free tier and an SMTP relay attracts abuse, and aggressive screening protects the shared pool everyone’s deliverability depends on. It may well be why placement holds at 88 percent. It is still the single largest reason not to build a business-critical send path here without a fallback.

Both support scores are the lowest we have recorded

Capterra scores customer service at 3.9, below GetResponse’s 4.0, which was the previous floor. G2’s headline of 3.9 is also the lowest in our set. In the corpus roughly 9 excerpts criticise support against roughly 5 that praise it, and the harsh end is very harsh: “the support is of the lowest standard possible,” “very bad support desk, very risky,” “poor customer service, lousy rules and no loyalty,” “no live chat, email auto-response fails.”

Support quality and the suspension pattern compound each other. Being cut off is survivable if someone answers. Several reviewers describe being cut off and then not reached.

Three gates the pricing page does not lead with

First, the free plan’s 200-a-day cap. Six thousand a month sounds generous until a product launch needs 2,000 in an afternoon. Second, the Mailjet logo stays on your emails until Essential, two tiers up. Third, and hardest for a marketing buyer, automations are Premium-only. A reviewer puts it in four words in the Cons field: “automation only premium.” Another, in French, adds that the automation tool itself “est en retard” – it is behind.

A German reviewer names the thing nobody else will

A two-star review from February 2025 reads: “Mailjet lässt sich einfach bedienen und ist… das System wird leider kaum noch weiterentwickelt.” Mailjet is easy to use, and the system is unfortunately barely being developed any further.

That is one reviewer and we are not turning it into a roadmap claim. But it is consistent with what the rest of the page shows: a product with an excellent technical foundation, a partial rather than official MCP story, around 95 integrations, automations parked behind the top tier, and an owner that sells Mailgun alongside it. If you are choosing for five years, ask Sinch directly where Mailjet sits in its plans.

Templates and customisation stop earlier than reviewers want

Roughly 6 excerpts name template or design limits, in three languages: “template customization not flexible,” “template ou thème pas assez nombreux,” “limited customization ability,” “les fonctionnalités de design qui sont limitées,” “custom fonts aren’t supported.” There is an irony worth naming: the company that gave the industry its best email markup language ships a template library its own users find thin.

The interface is slow, and has been for years

Roughly 5 excerpts describe lag or bugs, spanning 2019 to 2026: “UI is too slow,” “buggy UI,” “interface web peut parfois connaître quelques ralentissements,” “je rencontre quelques bugs de temps en temps,” “there are a few bugs from time to time.” Not fatal, and consistent enough over seven years to be a property rather than an incident.

Account risk: not rated, and here is why that is unsatisfying

What real users actually say

We read 3 pages of Capterra reviews, 75 rendered rows, deduplicated on the exact record, leaving roughly 74 distinct. Around a third are not in English, mostly French, and were read in the original.

The distribution is the harshest we have measured on any platform. Roughly 11 one-star and 6 two-star reviews in 74, about 23 percent of the corpus. For comparison, GetResponse ran at 12 percent, ActiveCampaign at 9 and Klaviyo at 2. That tail is why G2 sits at 3.9.

The mixed cluster is the product itself against the account experience, and it is the starkest split in our whole review set. The Pros fields are warm and consistent: easy, clean, reliable, good API, good price. The Cons fields, in the same reviews, describe being blocked. One five-star reviewer’s entire criticism is “block accounts without intimation.” Another five-star says “early accounts suspended, emails bounced.” These people like the software. They are warning you about the relationship.

The second cluster is price, and it is unusual in shape. Roughly 7 excerpts call it expensive, but the recurring complaint is not the headline number, it is what each tier withholds: the logo, the automations, the daily cap. “Very limited for the free and basic versions” is the summary a reviewer offered, and it is fair.

Ratings breakdown

Six categories, scored 1 to 10. The overall is the unweighted arithmetic mean, rounded to one decimal.

Who should still use Mailjet

Third-party validation

All figures read on August 27, 2026.

The G2 score of 3.9 is the lowest we have recorded for any platform on this site, against 4.1 for Constant Contact, 4.3 for GetResponse and 4.8 for Flodesk. The Capterra sub-score for customer service, also 3.9, is likewise the lowest we have seen.

The gap between the two panels is 0.3, under our 1.5 point threshold for a formal divergence analysis, so we will not run one. But the direction repays a sentence. G2’s sample is smaller here (176 against 455) and skews to business software buyers evaluating a stack; Capterra’s is larger and skews to smaller senders. The harsher score comes from the audience most likely to have had a procurement-grade experience of an account being stopped.

One thing worth stating plainly, because a star rating cannot. The engineering reputation and the customer score point in opposite directions here, and both are real. MJML is a genuine contribution to the whole industry. A 3.9 on G2 is a genuine verdict from paying customers. This review is the attempt to hold both at once rather than pick the flattering one.

Top 3 alternatives

• Brevo is the closest match and the clear upgrade: French-adjacent European vendor, real SMTP relay, an official MCP server, automation included far lower down, and a permanent free tier without a daily cap. We rate it 7.7 against Mailjet’s 6.1.
• Postmark is the answer if transactional reliability is the actual requirement. It does one job, its placement is measured and high, and it ships a 24-tool official MCP server. From $15/mo, and we rate it 7.8.
• Moosend is the cheap alternative with a relay: $9/mo with unlimited sends and support that its corpus praises far more warmly than Mailjet’s. Smaller ecosystem, and its own ownership caveats.

Full ranked coverage on the Mailjet alternatives tab.

Continue reading

• Mailjet pricing 2026 – the ladder, the 200-a-day free cap, the logo gate and the Premium automation gate.
• Mailjet SMTP settings – hostnames, ports and credential format for the relay.
• Mailjet API – the REST surface, MJML, and where the MCP story stands.

Frequently asked questions

How much does Mailjet cost? There is a free plan at 6,000 emails a month with unlimited contacts, capped at 200 a day, then paid from $9/mo. Two gates to price in: the Mailjet logo stays on your emails until the Essential tier, and automations are Premium-only. Full ladder on our pricing tab.

Is Mailjet free? Yes, permanently, at 6,000 emails a month with unlimited contacts. The number that will actually bind you is the 200-a-day cap, which no launch survives. Reviewers in several languages praise the free tier and then name that cap.

What are the Mailjet SMTP settings? Mailjet publishes a real SMTP relay, which only three platforms in this comparison group do. Hostnames, ports and credential format are on our SMTP settings tab.

What is Mailjet? A French transactional and marketing email service, the first company launched by the Paris studio eFounders in 2010, owned by Sinch since the $1.9 billion Pathwire deal closed in December 2021. It released MJML, the open-source email markup language, in 2016. Full background on the Mailjet hub.

Mailjet vs SendGrid: which should a developer pick? Both are transactional-first with SMTP and REST. Mailjet’s advantages are MJML, European hosting and collaborative editing. Its disadvantages are the account-suspension pattern documented above and a customer-service sub-score of 3.9. If EU data residency is not a requirement, weigh that pattern heavily.

What are the best Mailjet alternatives? Brevo for a European vendor with fewer gates, Postmark for pure transactional reliability, Moosend for the cheapest relay. Full list on the alternatives tab.

Why does Mailjet have a lower rating than its reputation? Because the technology and the account experience diverge. Mailjet wrote MJML and ships a good API and a real SMTP relay. It also scores 3.9 on G2, the lowest in our set, with roughly 19 percent of recent reviews describing an account blocked or suspended. Both facts are true and this review reports both.

Changelog

• August 27, 2026: Review published. Rated 6.1/10. G2 and Capterra read the same day. Roughly 74 distinct Capterra reviews across 3 pages, a third not in English. Deliverability from the EmailToolTester panel. Trustpilot recorded as N/A. Ban tolerance left unrated despite the strongest enforcement signal in our set, because no published policy was found.
• 7 December 2021: Sinch closed its $1.9 billion acquisition of the Pathwire group, which included Mailjet and Mailgun. The two are still sold separately.
• October 2019: Mailgun acquired Mailjet.
• 2016: Mailjet released MJML as open source. It is now used across the industry, including by competitors.
• August 2010: Registered in Paris by Wilfried Durand and Julien Tartarin, the first company launched by the eFounders studio.