Swagger Viewer for VS Code: Explore Best Extensions

When you work with APIs, Swagger and OpenAPI files are unavoidable. If you’re using VS Code, the natural instinct is to look for an extension that can preview these files without leaving the editor.

That works in many cases. But not always.

For moments when you just want to open a Swagger file instantly without configuring anything, you can also use a lightweight online Swagger Viewer. I’ll come back to that shortly.

How Swagger Viewing Works in VS Code

VS Code does not support Swagger or OpenAPI files out of the box. To preview them, you need an extension from the marketplace.

Most Swagger-related extensions support OpenAPI 2.0 and 3.x and provide a rendered preview panel inside the editor.

How to Install a Swagger Viewer Extension in VS Code

If you’ve never set this up before, here’s the simplest way to get started.

Step 1: Open the Extensions Panel

In VS Code, click on the Extensions icon in the sidebar or press:

Ctrl + Shift + X

Step 2: Search for Swagger or OpenAPI

In the search bar, look for keywords like:

• Swagger Viewer
• OpenAPI Viewer
• OpenAPI Preview

Choose an extension with good reviews and recent updates. Avoid ones that haven’t been maintained for years.

Step 3: Install and Reload

Click install, then reload VS Code if prompted. Once installed, open your Swagger JSON or YAML file.

Most extensions add a “Preview Swagger” or “OpenAPI Preview” option via right-click.

A Simple Swagger JSON Example

Here’s a minimal OpenAPI file that most extensions can render without issues:

{
  "openapi": "3.0.1",
  "info": {
    "title": "User API",
    "version": "1.0.0"
  },
  "paths": {
    "/users": {
      "get": {
        "summary": "List users",
        "responses": {
          "200": {
            "description": "OK"
          }
        }
      }
    }
  }
}

For small specs like this, VS Code extensions usually work fine.

Where VS Code Swagger Viewers Start to Break Down

In real projects, Swagger files rarely stay small.

From personal experience, these are the issues I’ve run into most often:

• Large files cause the preview to freeze
• External $ref files don’t resolve correctly
• No clear error when the spec is invalid
• Preview silently fails after extension updates

At that point, debugging the API becomes harder than it needs to be.

When an Online Swagger Viewer Is the Better Option

There are many cases where opening VS Code isn’t even necessary.

• You received a Swagger file from another team
• You’re reviewing a pull request
• You want to quickly inspect an API response
• You’re working on a locked-down machine

In those situations, using a browser-based tool is faster and more reliable.

An online Swagger Viewer lets you paste or upload a Swagger file and view the documentation instantly, without installing extensions or changing your editor setup.

Quick Validation Example

Here’s a common mistake that’s easier to catch in an online viewer:

{
  "info": {
    "title": "Missing Version API"
  }
}

Without the required OpenAPI version, most viewers will flag this immediately, saving you time.

VS Code Extension vs Online Swagger Viewer

• Actively editing APIs: VS Code extensions
• Reviewing or debugging specs: Online viewer
• Large or shared files: Online viewer
• Quick inspection: Online viewer

Final Thoughts

Swagger Viewer extensions in VS Code are useful tools, especially during development. But they’re not always the most reliable choice for viewing or validating API specs.

For quick checks, reviews, or large Swagger files, using a dedicated online viewer is often the simpler option.

If you want to view Swagger or OpenAPI files without setup or extensions, you can use Swagger Viewer here:

Swagger Viewer Online