langcodec-cli

langcodec is a localization CLI for teams shipping real apps, not demo files.

It handles the annoying parts of localization work in one place: format conversion, catalog cleanup, AI-assisted translation, translator-facing comment generation, and Tolgee sync for Apple string catalogs.

Supported formats:

• Apple .strings
• Apple .xcstrings
• Android strings.xml
• CSV
• TSV

Why It Feels Useful

Most localization tooling does one small thing. langcodec is designed to cover the loop teams actually run:

1. Convert strings between iOS, Android, and spreadsheet formats.
2. Inspect what is missing, stale, or still needs review.
3. Normalize files so diffs stop being noisy.
4. Draft translations with AI.
5. Generate better comments for translators from real source usage.
6. Pull from and push back to Tolgee without custom glue scripts.

The Cool Stuff

AI translation with real workflow support

langcodec translate \
  --source Localizable.xcstrings \
  --source-lang en \
  --target-lang fr,de,ja \
  --provider openai \
  --model gpt-5.4

translate is built for app catalogs, not just raw text:

• updates multi-language files like .xcstrings in place
• supports multiple target languages in one run
• can prefill from Tolgee before using AI fallback
• shows live progress with --ui auto|plain|tui
• validates output before model requests
• prints a clear result summary at the end

AI-generated translator comments

langcodec annotate \
  --input Localizable.xcstrings \
  --source-root Sources \
  --source-root Modules \
  --provider openai \
  --model gpt-5.4

annotate looks through your codebase and writes better .xcstrings comments for translators while preserving manual comments.

Tolgee sync without a pile of project scripts

langcodec tolgee pull
langcodec tolgee push --namespace WebGame

Tolgee support in v1 is intentionally focused on Apple .xcstrings. langcodec.toml can now be the source of truth, and langcodec will synthesize the Tolgee CLI JSON config at runtime.

Install

cargo install langcodec-cli

Quick Start

Use the CLI help for exact flags:

langcodec --help
langcodec translate --help
langcodec annotate --help
langcodec tolgee --help

Core Workflows

Convert between ecosystems

langcodec convert -i Localizable.xcstrings -o translations.csv
langcodec convert -i translations.csv -o values/strings.xml

Find strings that still need work

langcodec view -i Localizable.xcstrings --status new,needs_review --keys-only
langcodec stats -i Localizable.xcstrings --json

Edit files without format-specific tooling

langcodec edit set -i en.strings -k welcome_title -v "Welcome"
langcodec edit set -i values/strings.xml -k welcome_title -v "Welcome"

Normalize files for cleaner diffs

langcodec normalize -i 'locales/**/*.{strings,xml,csv,tsv,xcstrings}' --check

Sync or merge existing translation assets

langcodec sync --source source.xcstrings --target target.xcstrings --match-lang en
langcodec merge -i a.xcstrings -i b.xcstrings -o merged.xcstrings --strategy last

Example Config

[openai]
model = "gpt-5.4"

[translate]
concurrency = 4
use_tolgee = true

[translate.input]
source = "locales/Localizable.xcstrings"
lang = "en"
status = ["new", "stale"]

[translate.output]
lang = ["fr", "de"]
status = "translated"

[tolgee]
project_id = 36
api_url = "https://tolgee.example/api"
api_key = "tgpak_example"
namespaces = ["WebGame"]

[tolgee.push]
languages = ["en"]
force_mode = "KEEP"

[[tolgee.push.files]]
path = "locales/Localizable.xcstrings"
namespace = "WebGame"

[tolgee.pull]
path = "./tolgee-temp"
file_structure_template = "/{namespace}/Localizable.{extension}"

[annotate]
input = "locales/Localizable.xcstrings"
source_roots = ["Sources", "Modules"]
concurrency = 4

Then run:

langcodec translate
langcodec annotate
langcodec tolgee pull

When exactly one provider section is configured, translate and annotate use it automatically. If you configure multiple providers, choose one with --provider or translate.provider.

For larger repos:

• use translate.input.sources = [...] to fan out translation runs
• use annotate.inputs = [...] to annotate multiple catalogs in place

Main Commands

• convert: convert between localization formats
• view: inspect entries, statuses, and keys
• stats: summarize coverage and completion
• edit: add, update, or remove entries
• normalize: rewrite files into a stable form
• diff: compare two localization files
• sync: update existing target entries from a source file
• merge: combine multiple inputs into one output
• translate: draft translations with AI-backed providers
• tolgee: pull and push mapped .xcstrings catalogs with Tolgee
• annotate: generate translator-facing .xcstrings comments with AI-backed source lookup
• debug: inspect parsed output as JSON

Best Fit

langcodec shines when you are:

• shipping both iOS and Android apps
• moving strings through translators, spreadsheets, and app catalogs
• trying to reduce localization drift in CI
• replacing fragile one-off scripts with one repeatable tool

Related Docs

• Root overview: README.md
• Rust library crate: langcodec/README.md

License

MIT