Translate your app

Show Pinecart in English, Hindi and Tamil, with money and dates formatted for each locale, from one deployment.

Before you start: a MainSDK app with a main.yaml. The calls are described on Languages and formats.

1. Set your locales

i18n:
  driver: files            # files | tolgee | crowdin | lokalise | ai-draft
  locales: [en-IN, hi-IN, ta-IN]

2. Write the messages

Messages live in locales/, one file per locale:

orders.count: "{count, plural, one {# order} other {# orders}}"
orders.total: "Total: {total}"

orders.count: "{count, plural, one {# ऑर्डर} other {# ऑर्डर}}"
orders.total: "कुल: {total}"

Messages use Unicode MessageFormat 2; ICU MessageFormat strings, like the plurals above, are converted when they load. Both cover plurals, genders and selections.

3. Use them in your UI

import { t, i18n } from "mainsdk";

export function orderSummary(orders: { total: number }[]) {
  const total = orders.reduce((sum, o) => sum + o.total, 0);

  return {
    dir: i18n.dir(),
    heading: t("orders.count", { count: orders.length }),
    total: t("orders.total", { total: i18n.format.money(total, "INR") }),
  };
}

Render these values in your component, and set dir on its root element.

i18n.format.money(125000, "INR") gives ₹1,25,000.00 in en-IN. Formats come from Unicode CLDR. i18n.format.date() and i18n.format.number() work the same way, and i18n.dir() returns the text direction for right-to-left scripts.

4. Know how the locale is chosen

The user's choice comes first, then their account, then the browser. The locale is never guessed from the IP address alone. Market and locale resolve per request, so one deployment serves every market.

Wrap a handler in i18n.handle(req, () => …, { user }) to run it in the negotiated locale; t() and i18n.format.* then use it.

A missing message falls back along a chain: hi-IN, then hi, then en-IN, then en. Production never shows a key: a message missing everywhere returns an empty string and logs MAIN-I18N-0009. Locale-specific email and notification templates (templates/order.shipped.hi-IN.yaml) are planned.

5. Verify it worked

npx mainsdk check

A missing translation fails the check, not the user: a key missing from a locale under i18n.required is MAIN-I18N-0001, with the file and line of the t() call. Run npx mainsdk i18n pseudo to get long, accented and right-to-left pseudo-locales that catch layout breaks before a translator sees them.

Draft new strings with AI

With the ai-draft driver, npx mainsdk i18n draft --locale hi-IN drafts missing strings through ai, following the glossary in i18n.ai-draft.glossary. Each draft is held as pending in locales/.drafts/; a person approves it with i18n.drafts.approve(id) before any user sees it. An app agent can't approve (MAIN-I18N-0007).

Keep your translators' tools

npx mainsdk i18n export --format xliff and npx mainsdk i18n import <file> move strings to and from XLIFF, iOS .xcstrings, Android strings and ICU JSON. Generating Android values-hi/ and iOS .xcstrings from the same locale files is planned for phase 3.

Next

• Languages and formats
• main.yaml and overlays
• The check