Streamlining App Store Localization: Automating Metadata with metafill

For developers scaling their applications globally, localization is a critical but resource-intensive requirement. Managing descriptions, subtitles, and keywords across dozens of locales in App Store Connect is traditionally a manual process involving significant repetition and a high probability of data-entry error.

At poTeam, we identified the need for a more efficient, secure, and scriptable way to handle this workflow. The result is metafill: a free, open-source CLI tool designed to automate the translation and upload of App Store metadata.

The Problem: The Localization Bottleneck

Manual localization often forces a trade-off between global reach and developer time. Navigating the App Store Connect interface for each individual locale is inefficient, especially when handling frequent updates. While several third-party GUI tools exist to address this, many require subscriptions or necessitate sharing sensitive API keys with external cloud platforms.

The Solution: How metafill Works

Metafill is a high-performance command-line utility that integrates directly into your existing development or CI/CD pipelines. It automates the end-to-end metadata lifecycle:

1. Automated Translation: Metafill utilizes the Google Gemini API to machine-translate your base metadata into all supported App Store locales. This provides an immediate, scalable baseline for global presence.

2. Direct API Integration: Once translated, the tool uses the official App Store Connect API to upload the metadata directly to your app version. This eliminates the need for manual copy-pasting and web interface navigation.

3. Bring Your Own Key (BYOK) Security: Metafill is designed with security as a priority. It operates entirely on your local machine; no data is ever transmitted to poTeam servers. You provide your own Gemini and App Store Connect API keys, ensuring you maintain full control over your credentials.

Open Source and Transparent

Metafill is released under the MIT license. By open-sourcing the tool, we allow the developer community to verify its security and contribute to its evolution. It is a lightweight, transparent alternative for those who prefer the flexibility of a CLI and the security of a local-only workflow.

Access metafill and documentation to start automating your metadata workflow.