DevLingo

Translate developer content without leaving VS Code.

DevLingo is a VS Code extension that translates code comments, selected text and Markdown documentation directly inside the editor. It helps you read unfamiliar comments and produce translated documentation while keeping code and Markdown syntax intact.

It supports OpenAI, DeepL and Google Cloud Translation through a Bring Your Own Key (BYOK) model. Choose a provider, configure your own API key, and start translating from native VS Code menus.

DevLingo v1.0.0 is the first stable release. Install it from a trusted VSIX package. VS Code Marketplace publication is the next distribution step.

Quick Start

1. Install the DevLingo VSIX in VS Code 1.140.0 or later.
2. Open a file and click the globe icon in the editor title toolbar, or run DevLingo: Open in the Command Palette.
3. Choose Translation Provider: OpenAI, DeepL or Google Cloud Translation.
4. Choose Configure Provider API Key, select that provider and enter its key in the masked input.
5. Choose Target Language: English, French, Spanish or German.
6. Hover a supported code comment, translate a selection, or open a saved Markdown file and choose Translate Markdown File.

DeepL is the default provider, French is the default target, and comment translation is enabled by default. Every provider requires your own key.

Installation

Install from VSIX

Use a trusted devlingo-1.0.0.vsix supplied by the maintainer, or build it from this repository.

code --install-extension devlingo-1.0.0.vsix

Alternatively, open VS Code → Extensions → … → Install from VSIX… and select the file. To replace a previous local build, add --force to the command above.

DevLingo is not yet published to the VS Code Marketplace. Marketplace publication is the next distribution step.

Features

Translate comments on hover

Open a supported source file and hover a comment:

// Fetch the authenticated user from the API
const user = await getCurrentUser();

DevLingo detects the comment, extracts its text and translates it through the selected provider. The result appears in the native VS Code hover UI, with DevLingo and the target language in the heading. The source code remains unchanged. Empty comments are ignored.

Supported language IDs are javascript, javascriptreact, typescript, typescriptreact, vue, php, css, scss, less, python, shellscript and html. DevLingo recognizes language-appropriate //, #, /* … */ and <!-- … --> comments, including supported embedded script/style regions in HTML and Vue.

Detection uses a conservative lexical scan rather than a complete language parser. Report missed or incorrectly detected comments with a minimal example through GitHub Issues.

Translate selected text

1. Select non-whitespace text in an editor.
2. Open DevLingo and choose Translate Selection.
3. Choose the target language in the selection-specific picker.
4. DevLingo translates through the current provider and opens the result in a temporary plaintext document beside the source.

The source document is unchanged. This action has its own language picker; it does not change the saved default target language. Save the result if you want to keep it.

You can also right-click a selection and choose DevLingo: Translate Selection, or run that command from the Command Palette.

Translate Markdown files

Open a saved local Markdown file, choose your default target language, then run DevLingo: Translate Markdown File from the command center, editor context menu or Command Palette.

README.md
    ↓ DevLingo: Translate Markdown File (French)
README.fr.md

DevLingo reads the current editor content, translates prose and writes a new file in the same folder. It adds the target language code before the original extension:

Source	Target	Output
README.md	French (fr)	README.fr.md
guide.md	Spanish (es)	guide.es.md

DevLingo does not overwrite the original Markdown file. A progress notification names the source, and the translated document opens on success. If the output already exists, choose Replace or Cancel. Unsaved output documents must be saved or closed before replacement.

Untitled documents must be saved first. Markdown file translation currently supports local file: documents.

Markdown Preservation

Translate content, preserve structure. DevLingo translates prose fragments and replaces only their original source ranges; it does not rebuild or reformat the entire document.

Markdown content	Behavior
Headings and paragraphs	Translate text; preserve markers and layout
Bold, italic and strikethrough	Translate text; preserve delimiters
Ordered/unordered lists, task lists and blockquotes	Translate text; preserve markers and structure
GFM tables	Translate cell text; preserve table syntax
Inline code and fenced/indented code blocks	Preserve unchanged
Markdown links	Translate explicit labels; preserve destinations and titles
Raw URLs and autolinks	Preserve unchanged
Images	Preserve complete syntax, including alt text
Reference definitions	Preserve unchanged; full reference-link labels can be translated
Shortcut/collapsed reference links	Preserve unchanged to avoid breaking references
Horizontal rules	Preserve unchanged
Leading YAML frontmatter	Preserve a paired --- block with a --- or ... closing delimiter
HTML nodes, comments and paired HTML regions	Preserve unchanged, including enclosed text
Existing escapes, entities and line endings	Preserve source syntax

For example, given this input:

# Installation

Run `npm install devlingo`.

```bash
npm install devlingo
```

Read the [documentation](https://example.com).

A conceptual French translation is:

# Installation

Exécutez `npm install devlingo`.

```bash
npm install devlingo
```

Consultez la [documentation](https://example.com).

The inline command npm install devlingo, fenced code and https://example.com remain unchanged. This example illustrates preservation; wording depends on the provider.

Prose is translated in fragments around markup and line boundaries, so providers may have less context than when translating a complete paragraph. HTML content and image alt text are not translated. An unclosed HTML tag can conservatively protect the remainder of the document. Arbitrary frontmatter formats, MDX and every custom Markdown dialect are not guaranteed. Put identifiers that must remain literal in inline code and review output for your renderer.

See Markdown behavior and limitations for details.

DevLingo Command Center

The globe icon in the editor title toolbar opens a native VS Code QuickPick command center. It displays the current provider, target language and comment translation state.

Action	Purpose
Translate Selection	Translate selected text; visible when a non-empty selection exists
Translate Markdown File	Translate the active Markdown document; visible in a Markdown editor
Target Language	Change the default target for comments and Markdown
Translation Provider	Select OpenAI, DeepL or Google Cloud Translation
Comment Translation	Toggle hover translation; shows Enabled or Disabled
Configure Provider API Key	Open secure credential configuration
DevLingo Settings	Open the extension's native VS Code settings

All commands are also available in the Command Palette. Selection and Markdown actions have editor context-menu entries. DevLingo: Remove Provider API Key is available in the Command Palette and asks for confirmation before deleting a saved key.

Translation Providers

Provider	API Key Required	Status
OpenAI	Yes	Supported
DeepL	Yes	Supported; default
Google Cloud Translation	Yes	Supported

Open DevLingo → Translation Provider to switch. Changes take effect without reloading VS Code, and translation caches are renewed when the provider or credentials change. DevLingo does not automatically switch providers after a failure.

OpenAI

Uses the OpenAI API through the official SDK and Responses API. Configure an OpenAI API key for an API account with access to the extension's configured model. There is no ChatGPT sign-in flow or model picker in v1.0.0. See provider implementation details.

DeepL

Uses the official DeepL SDK. Configure your DeepL API key; the SDK selects the endpoint appropriate to the key. English output uses US English. DeepL is DevLingo's default provider.

Google Cloud Translation

Uses Cloud Translation Basic v2 through the official Google Cloud SDK. Configure a Google Cloud API key with the required API access, key restrictions and project billing/quota. Advanced v3 and service-account authentication are not supported.

Provider account access, billing, quotas and service availability are managed by the provider. Provider documentation covers implementation and how to add another provider.

Bring Your Own Key

BYOK means Bring Your Own Key. You use an API key from your chosen provider. DevLingo does not sell translation credits, proxy requests through a DevLingo backend or bundle provider credentials. Translation requests go directly to the selected provider.

Configure an API key

1. Open DevLingo from the editor toolbar or Command Palette.
2. Choose Configure Provider API Key.
3. Select OpenAI, DeepL or Google Cloud Translation.
4. Enter your key in the masked input and confirm.
5. DevLingo stores the key through VS Code SecretStorage.
6. Select that provider through Translation Provider, then translate normally.

Saving a key does not select its provider or validate it remotely. Provider and credential changes take effect without reloading. If a key is missing, DevLingo offers Configure or Later. Configure opens the selected provider's masked input directly; Later keeps the provider selected without translating.

SecretStorage and security

Provider API keys are stored using VS Code SecretStorage. They are not written to repository files, package.json, settings.json or workspace files. Credential commands do not reveal or prefill a saved key.

Never commit credentials or include them in public issues, screenshots or logs. Revoke exposed keys with their provider. See SECURITY.md for credential handling and vulnerability reporting.

Target Language

Open DevLingo → Target Language and choose:

Language	Code
English	en
French (default)	fr
Spanish	es
German	de

The saved target is reused for comment hover and Markdown translation. Translate Selection asks for a language for each invocation, using the same supported language list. Source language is automatically detected in normal UI workflows; there is no source-language setting or picker in v1.0.0.

Comment Translation Toggle

Open DevLingo → Comment Translation to toggle hover translation. Its description displays Enabled or Disabled. The change takes effect immediately. Selection and Markdown commands remain available when hover translation is disabled.

Settings

Open DevLingo → DevLingo Settings, or search for DevLingo in VS Code settings.

Setting	Default	Purpose
devlingo.translationProvider	deepl	Provider selection; application scope
devlingo.targetLanguage	fr	Default comment/Markdown target; can be overridden for a workspace
devlingo.commentTranslationEnabled	true	Comment hover toggle; application scope

API keys are configured through commands, never these settings.

Demo

The four screenshots above are real installed-extension captures. Comment and Markdown results were translated through DeepL into French. No GIF is bundled. See the demo script for the complete workflow and recording instructions.

Troubleshooting

Provider requires an API key

Choose Configure in the notification, or open DevLingo → Configure Provider API Key and configure the selected provider. Each provider has a separate saved key. Saving another provider's key does not satisfy the current provider.

Invalid API key

Check that the key belongs to the selected provider and has not expired or been revoked. Check provider-specific permissions and restrictions. Regenerate it in the provider account if needed, then save it again through DevLingo's masked input.

Translation provider quota reached

Check your provider account's billing, available credits and API quota. DevLingo cannot increase them. Exhausted credits/quota require a provider account change; a temporary rate limit may resolve after waiting and retrying.

Markdown output file already exists

Choose Replace to overwrite the translated output or Cancel to keep it. The original Markdown file is preserved. Save or close an unsaved translated output before replacement.

Comment translation does not appear

Check that Comment Translation is enabled, the correct provider is selected and its key is configured. Hover a non-empty comment in a supported language and syntax. Check network/provider availability. Hover failures remain quiet; try Translate Selection to see an actionable provider error.

Provider unavailable

Check your network, the provider's API service and account configuration. For Google Cloud, verify Cloud Translation Basic v2 is enabled and the API key restrictions allow it. If the provider setting contains an unsupported value, select OpenAI, DeepL or Google Cloud Translation explicitly.

If the problem persists, open a GitHub issue with your VS Code/DevLingo versions, provider name and a minimal non-sensitive reproduction. Never include an API key.

Privacy

DevLingo sends the content needed for translation directly to the selected external provider:

• Comment hover: extracted comment text, without delimiters.
• Selection: the selected text.
• Markdown: translatable prose segments; protected code, URLs, images and other protected ranges are not sent by this workflow.

Target-language information and provider-specific request instructions/options accompany the text. DevLingo does not scan or send the whole workspace. Hover and Markdown translations use bounded in-memory caches; they are not persisted. Markdown output is saved only as the requested translated file.

Review your provider's data policies before translating sensitive content. DevLingo does not make promises about an external provider's retention policy. See SECURITY.md.

Development

Requirements: Git, Node.js 22, npm and Visual Studio Code 1.140.0 or later.

git clone https://github.com/AndrixNg1/DevLingo.git
cd DevLingo
npm install
npm run lint
npm run compile
npm test

Open the repository in VS Code, press F5, and select Run Extension to launch an Extension Development Host. Tests use offline fixtures and injected clients, without real API keys. See development and packaging for headless Linux testing and VSIX validation.

The development/test mock is a deterministic fixture used by offline tests. See mock providers for development and testing; it is not selectable in the installed extension.

Project structure

src/
├── commands/
├── comments/
├── config/
├── hover/
├── markdown/
├── translation/
│   └── providers/
├── ui/
├── test/
└── extension.ts

Technical documentation

• Architecture
• Translation providers and adding a provider
• Markdown preservation and limitations
• Development, testing and packaging
• Contributing
• Security policy
• Roadmap and changelog

Contributing

Contributions are welcome: bug fixes, translation providers, language support, Markdown edge cases, documentation, UX improvements and tests. Start with CONTRIBUTING.md and follow the code of conduct.

Author

Connect with Andrix Ngoyi:

Support

Use GitHub Issues for reproducible bugs and feature requests. For vulnerabilities, follow the private reporting guidance in SECURITY.md.

License

DevLingo is licensed under the MIT License.