Go Memory Layout Visualizer

See the padding Go inserts. Reorder in one click.
Inline annotations, byte map, pack score, cache lines, amd64 / arm64 / 386

VS Code extension that shows how a Go struct sits in memory: the byte offset of each field, the padding the compiler adds between them, and how much of the struct is wasted space. When a reorder would shrink it, one click rewrites the field order for you (comments and tags kept).

30 seconds to it

type Sparse struct {
    Active bool    // 1B + 7B padding
    ID     uint64
    Tag    uint8   // 1B + 7B padding
    Name   string
}
// 40B, pack 65%, 14B wasted

Open the file, annotations appear, click Optimize Layout:

Sparse  40B  pack 65%  pad 14B
0000  A.......BBBBBBBB
0010  C.......DDDDDDDD
0020  DDDDDDDD
legend: A=Active  B=ID  C=Tag  D=Name  .=padding

After reorder: 32B, pack 85%, saved 8 bytes. Same fields, less air.

Why people install it

• Spot padding without running unsafe.Sizeof or reading the Go ABI by hand
• Cut struct size on hot types (API responses, events, DB models)
• Paste the ASCII map into a PR so reviewers see the waste
• Learn how alignment actually works

Install

In VS Code, Ctrl+P then:

ext install RhinoSoftware.go-memory-visualizer

Or from the Marketplace or Open VSX.

From source:

git clone https://github.com/1rhino2/go-memory-visualizer.git
cd go-memory-visualizer
npm install
npm run compile
# open in VS Code, press F5 for the Extension Development Host

Commands

Command Palette (Ctrl+Shift+P):

Command	What it does
Go: Show Memory Layout	Memory breakdown for every struct in the file
Go: Show Visual Memory Map	Byte grid + ASCII map for the struct at the cursor
Go: Optimize Struct Memory Layout	Reorder fields to cut padding
Go: Toggle Architecture	Switch amd64 / arm64 / 386
Go: Export Memory Layout Report	Export to JSON, Markdown, or CSV
Go: Analyze Workspace Memory Layout	Scan the workspace for padding and cache-line issues
Go: Compare Struct Layout Across Architectures	Side-by-side amd64 / arm64 / 386

Optimize is also a Quick Fix (Ctrl+.) on any reorderable struct, and the status bar shows the bytes you could save in the current file.

Config

Settings live under goMemoryVisualizer.* (default architecture, padding warning threshold, cache-line warnings, confirm-before-optimize, and more). Open VS Code Settings and search "Go Memory" to see them all.

Requirements

• VS Code 1.85.0 or higher
• Node.js 20+ to build from source

Development

npm install
npm run compile
npm test

See DEVELOPMENT.md for the internals and CHANGELOG.md for version history.

License

MIT, see LICENSE.