Mailjet

Most companies end up sending two completely different kinds of email. There are campaigns — newsletters, promotions, the things a marketer schedules — and there are transactional messages: password resets, receipts, order confirmations, the ones a developer triggers from code and nobody notices until they stop arriving.

These are usually bought separately, from different vendors, by different people, with two sets of domain reputation to manage. Mailjet's proposition is that they should not be.

This review covers whether the unified model actually pays off, why real-time co-editing solves a real organisational problem, what EU data residency changes for a European buyer, and where the Sinch ownership overlaps with HubSpot-style all-in-one alternatives.

One Account, Two Kinds Of Email

• Mailjet is an email platform that handles marketing campaigns and transactional sending from a single account, with tools for marketers and an API for developers.
• Owned by Sinch, alongside Mailgun and Email on Acid — worth knowing, because the sibling products overlap.
• Real-time co-editing in the email builder is genuinely rare and solves the marketer-designer-developer handoff.
• EU data centres with a 99.99% SLA, ISO 27001 and SOC 2 — which is why it wins European procurement against US-hosted rivals.
• The AI layer is practical rather than headline: campaign generation, tone rewriting, plain-language segmentation, and an MCP server for querying analytics from Claude.

Platform, Compliance And Ownership

Does One Platform For Both Actually Help?

The unified pitch is easy to state and worth examining, because it is genuinely right for some companies and genuinely wrong for others.

The strongest argument is sending reputation. Email deliverability depends on the reputation of the domain and IP you send from, and managing that across two vendors means two sets of authentication records, two warm-up processes and two places a problem can originate. One platform means one reputation to look after.

The second argument is visibility. When a customer says they did not receive something, being able to look in one place — was it the campaign or the receipt? — rather than two is a real support saving.

A dedicated campaign tool such as Hoppy Copy goes deeper on the writing and touches none of the sending. The counter-argument is specialisation. A pure transactional service optimises hard for throughput and latency; a pure marketing platform optimises for campaign tooling and CRM depth. A combined product is competent at both rather than exceptional at either.

The practical test: if the same team owns both kinds of email, unify. If your marketers and your engineers do not talk to each other and have different requirements, two specialised tools will each be better and the reputation overhead is manageable.

The real argument for one platform is not the feature list. It is having one sending reputation to protect instead of two.

Real-Time Co-Editing Solves An Organisational Problem

This is the feature least likely to appear on a comparison chart and most likely to change how a week goes.

Email production is a handoff problem. A marketer drafts, a designer adjusts, a developer fixes something in the template, someone in legal wants a line changed — and traditionally each step means exporting, sending, waiting and re-importing, with version confusion at every hop.

Co-editing in the builder collapses that into one document that several people are in at once, which is what Google Docs did to written documents fifteen years ago and email tooling has been slow to copy.

MJML support belongs to the same story. It is a markup language that compiles to the tortured table-based HTML email actually requires, and it means a developer can work in something maintainable rather than hand-editing nested tables.

Together they signal a platform designed for a team rather than for one person, which matches the subaccount feature for agencies and multi-brand companies.

EU Data Residency, And Why It Wins Deals

EU-based data centres, a 99.99% SLA, ISO 27001 and SOC 2, plus Certified Sender Alliance participation.

In an American review this reads as procurement filler. In a European one it is frequently the entire decision. Email lists are personal data, and a data protection officer who will not approve US-hosted processing will approve EU-hosted processing — regardless of which product has better campaign tooling.

The Certified Sender Alliance detail is more specialised and worth knowing. It is a German-led whitelist programme, and participation improves inbox placement with several major European mailbox providers. If your audience is in the DACH region that is a concrete deliverability advantage rather than a badge.

The deliverability toolkit around it is standard but complete: email validation before sending, dedicated IPs, domain authentication with DKIM and SPF, and reputation monitoring. Nothing exotic — and email deliverability is a field where doing the standard things properly beats doing clever things.

The AI Layer, Assessed Honestly

Four AI features, and they are unusually practical for a category that has attached AI to everything.

• AI Segmentation — describe an audience in plain language instead of building filter logic. This is the one that saves real time, because segment-building is fiddly and most marketers under-segment as a result.
• Mailjet AI Assistant — rewriting and tone adjustment inside the editor. Useful at the point of writing rather than as a separate tool.
• AI Email Generator — campaigns from a prompt. Fine as a starting point, and the usual caveat applies: generated marketing copy reads as generated unless you rewrite it.
• MCP server — query your campaign analytics from Claude Desktop. Genuinely novel, and the most interesting of the four for anyone who would rather ask a question than build a report.

Choosing Between Mailjet And Its Siblings

Because Sinch owns Mailjet, Mailgun and Email on Acid, an obvious question arises: which one are you supposed to buy?

The rough division is that Mailgun is the developer-first transactional product and Mailjet is the one with the marketing platform attached. If you only send transactional email and no human will ever open a campaign builder, the sibling is likely the better fit.

Against the wider market, the comparison depends on what else you need. HubSpot AI puts email inside a CRM, which is a much larger commitment and the right one if email is part of a sales motion rather than a channel of its own.

One thing worth verifying yourself: the customer list includes DHL, American Express, Microsoft and Wikipedia, and the site cites 100,000+ customers. Those are Mailjet's own figures, and logos on a marketing page usually mean somebody at that company has an account rather than that the company runs on it. Test deliverability with your own list instead — it is the only number that will matter to you.

1. Decide first whether one team owns both marketing and transactional email. That answers the unify-or-specialise question.
2. Check data residency requirements with whoever owns data protection before evaluating features.
3. Warm a dedicated IP properly if you are moving volume — reputation does not transfer between providers.
4. Set up DKIM and SPF authentication on day one rather than after the first deliverability problem.
5. Test inbox placement to your actual audience's mailbox providers, not to a test account.
6. Try AI Segmentation on a segment you already built by hand, to see whether it matches.
7. If several people touch an email before it sends, use co-editing rather than exporting — that is the workflow the platform is built around.