SFMC Language Service for VS Code

A Visual Studio Code extension providing comprehensive language support for Salesforce Marketing Cloud — AMPscript, SSJS (Server-Side JavaScript), and GTL (Guide Template Language).

Features

Syntax Highlighting

• AMPscript block syntax (%%[ ... ]%%)
• Inline AMPscript expressions (%%= ... =%%)
• <script runat="server" language="ampscript"> blocks (flexible attribute order, single/double quotes)
• Variables (@name), system variables (@@ExecCtx), keywords, operators, strings, comments, function calls
• Personalization strings (%%FirstName%%, %%emailaddr%%)
• Guide Template Language (GTL) expressions ({{Name}}, {{Lookup(...)}})
• Content syndication patterns (%%HTTPGet "url"%%)

Auto-Completion

• 147 AMPscript functions with snippet-style parameter placeholders, organized across 15 categories (Data Extension, HTTP, Content, Encryption, Math, String, Date/Time, Utility, SOAP API, Salesforce, Dynamics CRM, MobileConnect, Social, Einstein, and more)
• 16 keywords with contextual snippets (var, set, if/then/elseif/else/endif, for/to/downto/do/next, and/or/not, true/false)
• 80+ system personalization strings with descriptions (subscriber identity, email/job metadata, dates, sender info, URLs, MobileConnect demographics, GroupConnect, execution context)
• File-scoped variable suggestions extracted from the current document
• Context-aware — completions only appear inside AMPscript regions

Hover / IntelliSense

• Typed function signatures with parameter documentation
• Required/optional parameter markers
• Return type information
• Usage examples
• Keyword and personalization string documentation

Signature Help

• Parameter hints while typing function arguments
• Active parameter highlighting as you type commas

Diagnostics

• Delimiter matching: Unmatched %%[/]%% and %%=/=%% pairs (both directions)
• Nesting-aware control flow: Stack-based IF/ENDIF and FOR/NEXT validation with line-level error locations
• Unknown function detection: Flags function calls not in the AMPscript catalog
• Best-practice hints: Informational warnings for bare subscriber attribute access without AttributeValue() wrapping

SSJS (Server-Side JavaScript)

• Auto-completions for Platform.Function.*, Platform.Variable.*, Platform.Response.*, Platform.Request.* methods
• Core library objects with method listings (DataExtension, Subscriber, TriggeredSend, etc.)
• WSProxy method completions
• Hover documentation for SSJS globals, Platform functions, and Core library objects
• Diagnostics: Missing Platform.Load("core", "1") detection, ES6+ syntax warnings

GTL (Guide Template Language)

• Context-aware completions inside {{ }} expressions — AMPscript functions, variables, and personalization strings
• GTL snippets for common patterns

Snippets

AMPscript snippets (36 built-in):

SSJS snippets (18 built-in):

GTL snippets (8 built-in):

File Types

This extension activates for:

• *.ampscript, *.amp -- AMPscript files
• *.ssjs -- Server-Side JavaScript files

Installation

Option 1: Install from VSIX

1. Build and package:

   npm install
   npm run compile
   npm run package
   

2. In VS Code: Extensions > ... > Install from VSIX... > select the generated .vsix file

Option 2: Run in Extension Development Host

1. Open the vscode-sfmc-language folder in VS Code
2. Run npm install and npm run compile
3. Press F5 and choose Launch Client
4. Open a .ampscript or .amp file in the Extension Development Host

Configuration

Architecture

vscode-sfmc-language/
├── client/              Language client (VS Code extension host)
│   ├── src/extension.ts   Starts the language server over IPC
│   └── src/test/          Integration tests (completion, diagnostics)
├── server/              Language server (Node.js LSP)
│   ├── src/server.ts        Completions, hover, signature help, diagnostics
│   ├── src/ampscriptData.ts AMPscript function catalog, keywords, personalization strings
│   └── src/ssjsData.ts     SSJS Platform functions, Core library objects, WSProxy
├── syntaxes/            TextMate grammars for syntax highlighting
│   ├── ampscript.tmLanguage.json   AMPscript + GTL grammar
│   └── ssjs.tmLanguage.json        SSJS grammar (extends JavaScript)
├── snippets/            VS Code snippet definitions
│   ├── ampscript.snippets.json     AMPscript snippets
│   ├── ssjs.snippets.json          SSJS snippets
│   └── gtl.snippets.json           GTL snippets
├── language-configuration.json      AMPscript bracket/comment/folding config
├── ssjs-language-configuration.json SSJS bracket/comment/folding config
└── package.json         Extension manifest

Development

npm install          # Install root + client + server dependencies
npm run compile      # TypeScript compilation (type-checked)
npm run watch        # Watch mode for development
npm test             # Run integration tests in VS Code instance
npm run lint         # ESLint
npm run package      # Package as .vsix

The extension uses esbuild for production bundling (vscode:prepublish), reducing load time and VSIX size.

Troubleshooting

Cannot find module 'undici-types'

npm install
npm run compile

Notes

• AMPscript function metadata is sourced from the ampscript-data shared package.
• SSJS function metadata is sourced from the ssjs-data shared package.
• This extension provides editing support for SFMC languages — it does not execute AMPscript or SSJS code.