HTTP Language

Full language support for HTTP requests in VS Code - syntax, auto-completion, and more.

REST Client Next provides comprehensive language support for HTTP request files with .http and .rest extensions. This includes syntax highlighting, auto-completion, code snippets, navigation, and more.

Activation

The HTTP language mode is automatically activated when:

1. File has extension .http or .rest
2. First line follows standard RFC 2616 request line format: Method SP Request-URI SP HTTP-Version

To manually enable, click the language mode indicator in VS Code’s status bar (bottom-right) and select HTTP.

Syntax Highlighting

• Request line - Method, URL, HTTP version
• Headers - Header names and values
• Body - Content with appropriate highlighting based on MIME type (JSON, XML, JavaScript, etc.)
• Comments - Lines starting with # or //
• Responses - When previewing responses, syntax highlighting is applied

Auto-Completion

Auto-completion triggers automatically or with Ctrl+Space. Supported categories:

1. HTTP Methods - GET, POST, PUT, DELETE, PATCH, HEAD, OPTIONS, etc.
2. HTTP URLs - From request history
3. HTTP Headers - Standard and custom headers
4. System Variables - {{$guid}}, {{$timestamp}}, etc.
5. Custom Variables - Environment, file, and request variables in current context
6. MIME Types - For Accept and Content-Type headers
7. Authentication Schemes - Basic, Digest, AWS, etc.

Code Snippets

Built-in snippets accelerate request authoring:

Type the snippet name and press Tab to expand.

Comments

Both comment styles are supported:

# This is a comment
// This is also a comment

GET https://api.example.com/users

Comments can appear anywhere in the file.

JSON & XML Support

Body Indentation

When pressing Enter inside {}, [], or <> brackets, automatic indentation is applied (configurable via rest-client.addRequestBodyLineIndentationAroundBrackets).

Auto-Closing Brackets

Type {, [, (, ", or ' and the closing character is automatically inserted.

Comment Conversion

Select code and type // or # to comment/uncomment multiple lines.

Goto Symbol

Navigate to requests and variables quickly:

• Press Ctrl+Shift+O (Cmd+Shift+O on macOS)
• Or press F1 and type @

Shows a list of:

• File-level variables (@variableName)
• Named requests (# @name requestName)
• Request blocks

Select to jump directly.

CodeLens

CodeLens displays actionable links above each request:

• Send Request - Send this request
• Send All Requests Sequentially - Send all requests in the file one after another

Toggle via:

• rest-client.enableSendRequestCodeLens
• rest-client.enableCustomVariableReferencesCodeLens (shows variable references)

Customize titles:

• rest-client.codeLensSendRequestTitle
• rest-client.codeLensSendAllRequestTitle

Folding

Request blocks can be folded/unfolded:

# @name myRequest
GET https://api.example.com/users
Authorization: Bearer token
# ... rest of request

Click the fold icon in the gutter or use:

• Ctrl+Shift+[ to fold
• Ctrl+Shift+] to unfold

Markdown Code Blocks

REST Client recognizes HTTP requests within Markdown fenced code blocks:

```http
GET https://api.example.com/users
```

Language identifier http or rest both work.

File Associations

By default, .http and .rest extensions are associated with the HTTP language. To add custom associations, add to your settings.json:

{
    "files.associations": {
        "*.api": "http"
    }
}

Manual Language Selection

If a file isn’t automatically recognized, change language mode:

1. Click language indicator in status bar (bottom-right)
2. Select HTTP from list
3. Or press Ctrl+K M (Cmd+K M on macOS) and choose HTTP

Language Features Summary

Tips

1. Save your file - Some features (like variable resolution, diagnostics) work best with saved files
2. Use named requests - # @name makes goto symbol and variable references more useful
3. Define file variables - @variable = value at the top for reusable values
4. Leverage auto-completion - Start typing variables, headers, or methods to see suggestions
5. CodeLens is your friend - Keep it enabled for quick one-click sending

Troubleshooting

No syntax highlighting?

• Ensure file extension is .http or .rest
• Or manually set language mode to HTTP

Auto-completion not working?

• Check that language mode is HTTP
• Wait for language server to initialize (~1-2 seconds after opening)
• Try Ctrl+Space to manually trigger

CodeLens missing?

• Verify rest-client.enableSendRequestCodeLens is true
• CodeLens may be disabled globally in VS Code: editor.codeLens setting
• Some themes hide CodeLens; try changing theme or adjusting workbench.colorCustomizations

Goto Symbol not showing variables?

• Ensure file variables start with @ on their own line
• Named requests must use # @name or // @name syntax
• File must be saved for registration

Performance Tips

For large files (100+ requests):

• Disable CodeLens if slow: "rest-client.enableSendRequestCodeLens": false
• Disable variable reference CodeLens: "rest-client.enableCustomVariableReferencesCodeLens": false
• Consider splitting into multiple files
• Increase rest-client.largeResponseBodySizeLimitInMB if dealing with large responses

Keyboard Shortcuts Reference

All shortcuts require HTTP/plaintext language mode:

Note: These shortcuts are exclusive to HTTP/plaintext mode to avoid conflicts with other extensions.