Feel Language Support for VS Code

Official VS Code extension for the Feel programming language — the AI-native backend language that compiles to standalone Go binaries.

Features

Syntax Highlighting

Full syntax highlighting for .feel files, including:

Keywords: let, define, taking, when, otherwise, route, respond, serve, record, agent, tool, and more
HTTP methods: GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS, WS
All 18 stdlib namespaces: db, ai, crypto, auth, list, map, string, json, time, file, math, validate, cache, mail, queue, security, env, http
String interpolation: "{variable} and {expression}"
Comments: -- single-line comments
Record types (PascalCase), functions, operators, and pipeline operator |

Snippets

40+ production-ready snippets for rapid development:

Prefix	Description
`hello-api`	Hello World REST API
`route-get`	GET route handler
`route-post`	POST route handler
`route-put`	PUT route handler
`route-delete`	DELETE route handler
`crud-rest`	Full CRUD scaffold
`auth-scaffold`	JWT auth (register + login)
`define`	Named function
`fn`	Lambda function
`when`	Conditional expression
`try`	Try/catch block
`record`	Record type definition
`db-connect`	Database connection
`db-query`	SELECT query
`db-exec`	INSERT/UPDATE/DELETE
`db-transaction`	Transaction block
`ai-ask`	AI question
`ai-classify`	Text classification
`agent`	AI agent definition
`tool`	Tool definition
`jwt-sign`	Sign JWT token
`auth-jwt`	Require JWT middleware
`validate`	Body validation
`list-map`	Map over list
`list-filter`	Filter list
`cache-compute`	Cache get-or-compute

Language Features

Auto-closing brackets: {}, [], ()
Comment toggling: -- comment with Ctrl+/
Bracket matching: Highlight matching pairs
Code folding: do { ... } blocks
Run current file: Click ▶ in editor title bar or use Feel: Run Current File
Format document: Feel: Format Document command (requires Feel interpreter)

Requirements

The syntax highlighting and snippets work out of the box with no dependencies.

For the Run File and Format Document features, you need:

Python 3.8+ (for interpreter mode)
The Feel project installed: git clone https://github.com/agil-bharata/feel

Extension Settings

Setting	Default	Description
`feel.interpreter.path`	`""`	Path to Feel's `main.py`. Auto-detected if left empty.
`feel.formatting.enable`	`true`	Enable format-on-save with feelfmt.

Language Overview

Feel is a minimal, readable backend language. Example:

-- Simple REST API
let conn = db.connect(":memory:")

route GET "/users" -> do {
  let rows = db.query(conn, "SELECT * FROM users", [])
  respond rows
}

route POST "/users" -> do {
  let data = validate.shape(body, "UserInput")
  db.exec(conn, "INSERT INTO users (name) VALUES (?)", [data["name"]])
  respond 201 map { id: db.last_id(conn) }
}

route DELETE "/users/{id}" -> do {
  db.exec(conn, "DELETE FROM users WHERE id = ?", [id])
  respond map { message: "deleted" }
}

serve on 3000 cors

Key Syntax Rules

Variables: let name = value (immutable)
Functions: define add taking a, b -> a + b
Lambdas: fn x -> x * 2
Conditionals: when x > 0 -> "pos" otherwise -> "neg"
Pipeline: data | json.decode | show
Comments: -- this is a comment
Naming: snake_case for variables/functions, PascalCase for record types

Feel Language

Dobith