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Get your API keys for XLIFF String Catalog Localizer app

Machine translation is a fast, convenient and cheap way to localize your apps. The quality is still not as good as a human translator. But for launching your MVP on time, releasing a new version to beta-testers across the globe or just checking how your screens look like in another language (like Spanish texts being 20% longer than in English), then speed and low cost can be more important to you than top quality.

Add to that the convenience this app offers you: no need to learn the XLIFF XML format and transform values to meet specific requirements of machine translator APIs. Just configure the XLIFF String Catalog Localizer app by pasting your personal API key(s) in the Settings screen and you can localize your app in minutes. Dozens of languages and hundreds of keys in multiple string catalogs, with pluralizations and other complexities, are localized with a few clicks.

Get access to the DeepL REST API for FREE without any risk. Sign up to obtain your personal API key here. You need a valid credit card to authenticate yourself, but nothing is charged.

The free API of DeepL translator has a limit of 500,000 characters per month.

Paste your personal API key in this section of the Settings screen. The API key field is secured: after pasting you only see dots. Click on the View key button to check.

If you already have a Pro or Business account the API must use a different url than for the free plan. Please change this settings if needed.

You can temporarily stop localizing via this API by checking Suspend. For instance if you have reached your monthly limit.

Obtaining a Google API key requires more steps than for DeepL and you need a Google account as starting point. Follow the instructions in the Create an API key section of this page. Your API key needs to be linked to a (placeholder) project you create in the Google Cloud services, selecting Cloud Translation v2. Like DeepL, you also need to authenticate with a valide credit card number. Your credit card will only be charged if you exceed the free limit, which is similar to the 500,000 characters per month of DeepL but calculated as a discount.

Paste your personal Google API key in this section of the Settings screen. The API key field is secured: after pasting you only see dots. Click on the View key button to check.

You can temporarily stop localizing via your Google Cloud Translation API by checking Suspend. For instance if you have reached your monthly limit.

This app only supports the v2 (Basic) version of Google Cloud Translation. It has the same localization quality as the more recent v3 (Advanced) API, which is designed to be used from within the Google cloud.

Select which API is used first

With your own translation rules you can obtain a translation quality not possible via APIs. Therefore, this app tries to localize via the built-in rule database. After that, if you have both DeepL and Google configured, you can choose which of both APIs is used first to localize strings. Once the first API has found a localization, this value is not overwritten by the second API.

How to choose the right API to localize your Xcode project:

DeepL TranslatorGoogle Cloud Translation
30 languages130 languages
Highest average quality localizations of European languages.Best choice for other than European languages. Almost as good as DeepL for European languages.
More informal tone of localizations in German, French, Italian, Japanese, Dutch, Polish, Portuguese, Russian and SpanishMore formal tone of localizations, for languages that have that distinction.
Fewer steps to sign-up and get an API key than Google. Best choice to start trying out machine localization via the XLIFF String Catalog Localizer app.More complex to get an API key versus DeepL.

Monitor your translator API usage

After each run via the Select button on the Translate screen, the default string characters localized via an API are logged. Check if you are still below your free monthly API limit with this graph on the Info screen:

Why only Google and DeepL?

Recent comparison of localization quality of the best machine and AI-based translation services, like this article from Lionbridge here, shows Google and DeepL consistently in top positions:

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