Translate email templates from Braze and Mailchimp

Every email platform localizes in one of three ways. Finding your platform in this table tells you what to upload and what you get back.

• If your platform generates translations for you and you only want to review them, that is a different job — bring the finished text in as existing translations so your memory and glossary learn from it.

Upload the template HTML. Every span Braze has tagged with {% translation %} becomes one string, keyed by that tag’s id, and everything outside a tag is left alone: untagged copy is text you told Braze not to localize, so translating it would put words in the file that Braze never varies.

What you export is the translation table, not a rewritten template. That is deliberate, and it is the part worth understanding: the text inside the tag is Braze’s default, what it sends to anyone whose locale you have no translation for. It has to stay in the source language. Translations belong in the CSV you upload to Braze alongside the template.

So the round-trip is: upload the template, translate, export Strings file (keyed) or the CSV, upload that to Braze. Your template never needs to change.

• Braze’s own limits are enforced at import, so you find out before the run rather than after: 200 translation tags per message, 2,000 characters of default text per tag, no nesting, and ids unique within the message.
• Tags inside an HTML attribute — a localized link target, for instance — are read like any other.
• Braze advises against opening its translation CSV in Excel, which mangles non-Latin characters. That warning applies to the file you upload back to Braze, whoever produced it.

Mailchimp has no multilingual campaign feature, so its templates carry every language inline and pick one with a conditional — *|IF:MC_LANGUAGE=es|* … *|ELSE:|* … *|END:IF|*. Hand-rolled Liquid templates do the same with {% if lang == "es" %}. Upload the template and Transept reads each conditional as one string, with each branch as that string’s translation for its language.

Every branch is translated as the standalone sentence it is, not as a variation on the default. This matters more than it sounds: the branch a returning customer reads and the branch a new one reads are usually different copy with different intent, and translating the whole conditional as one blob does both badly.

A language the template has never carried gets a new branch written into the file on export, placed before the default so the default stays the fallback. You upload one template and get one template back, now covering more languages.

• Conditionals that have nothing to do with language — {% if vip %}, *|IF:PURCHASES>0|* — are left completely alone, including their text. Only a test against Mailchimp’s MC_LANGUAGE or a Liquid variable that names a language counts.
• A language conditional nested inside one of those is still found and translated.
• A new branch is labelled with the language code Transept uses. If your platform expects a different spelling for that language, rename it in the exported file.

Then the template is just an HTML file, and that is the easiest case. Upload it, translate the whole thing, and export one file per language — the layout, inline styles, and table scaffolding that email HTML depends on come back untouched, because the export writes translations into your original file rather than rebuilding it.

Use several languages to produce every locale from one upload in a single run.

They are hidden from the AI before it sees the text and restored afterward, and every reply is counted against the source so nothing can go missing. This covers Liquid ({{first_name}}, {% if %}), Braze’s attribute syntax ({{${first_name}}}), Mailchimp merge tags (*|FNAME|*), and printf placeholders, with nothing to configure.

One thing inside a tag is translated, on purpose: the fallback text. In {{ first_name | default:"friend" }}, the word friend is what every recipient with no first name on file reads, often most of the send. That makes it copy, so it gets translated while the tag around it stays exactly as written.

Two limits are worth knowing before you plan a campaign, because neither is visible in a preview:

• Mailchimp subject lines cannot vary by language. The subject is campaign metadata rather than template content, so no conditional reaches it. That limit belongs to Mailchimp; Transept cannot work around it. If you need per-language subjects there, you need per-language campaigns.
• Untagged text in a Braze template stays untranslated, because Braze itself will never localize it. If a paragraph should vary by language, wrap it in a translation tag in Braze first, then re-import.
• A preview shows one language, which is exactly why both of these go unnoticed. Check the exported file, not the preview, before a send.