NATS Client for VS Code

Author .nats files and run NATS actions from the editor, in a REST Client-style workflow.

Main Features

• Send NATS actions from CodeLens in .nats files.
• Compose multiple actions in one file with ### delimiters.
• JetStream support (JSPUBLISH, JSCONSUME) and a JetStream Explorer view.
• Variables with completion and hover: {{token}} (stored in NATS Variables) and {{env:NAME}} (OS environment).
• Structured output channels (main output + per-subject channels).
• Connection management UI for saved and ad-hoc connections.

Usage

Create a .nats file and write an action block.

REQUEST nats://localhost:4222/lab.echo
NATS-Timeout: 5000
Trace-Id: randomId()

{
	"id": 1,
	"subject": "cpu"
}

Run the action using the CodeLens shown above the block.

Multiple actions in one file

Use ### to separate actions:

PUBLISH nats://localhost:4222/lab.events

{"event":"start"}

###

REQUEST nats://localhost:4222/lab.echo
NATS-Timeout: 5000

{"hello":"world"}

Install

Press F1, type ext install, then search for mfahmialkautsar.nats-client.

Making NATS actions

Each action block follows a request-line + headers + optional body format.

Request line

The first non-empty line is the action line.

SUBSCRIBE nats://localhost:4222/lab.events

PUBLISH nats://localhost:4222/lab.events

REQUEST nats://localhost:4222/lab.echo

REPLY nats://localhost:4222/lab.echo

Headers

• NATS-* headers configure action/session behavior (for example NATS-Timeout, server overrides, JetStream stream/durable).
• Other headers are forwarded as message headers.

Body

If present, the body is everything after the first blank line.

JetStream

JetStream actions are supported in .nats files.

@url = nats://localhost:4222
@stream = orders
@subject = orders.new
@consumer = monitor

JSPUBLISH {{url}}/{{subject}}
NATS-Stream: {{stream}}

{
  "id": "order-123",
  "status": "created"
}

###

JSCONSUME {{url}}/{{stream}}/{{consumer}}

See examples/jetstream.nats for a complete, runnable example.

JetStream Explorer

The JetStream Explorer view provides actions for streams and consumers:

• Refresh
• Create / Update / Delete Stream
• Create / Update / Delete Consumer
• View Stream Info / View Consumer Info

Variables

Variables are resolved before running actions:

• {{name}}: resolved from the active environment in the NATS Variables Explorer view.
• {{env:NAME}}: resolved from OS environment variables.

You can manage environments/variables from the NATS Variables view title buttons and context menus.

Views and commands

Explorer views:

• NATS Variables
• JetStream Explorer

Common commands:

• NATS: Manage Connections
• NATS: Reset Connections
• NATS: Show Output
• NATS: Show Subscriptions
• NATS: Show Reply Handlers

Configuration

Examples

Ready-to-run flows live under examples/:

• examples/pub-sub.nats
• examples/request-reply.nats
• examples/jetstream.nats

Development workflow

bun install
bun run watch
bun run test

Feedback

• Issues: https://github.com/mfahmialkautsar/vscode-nats-client/issues