alt Hacker NewsI did some debugging on this today. The results are... sobering.
Memory comparison of AI coding CLIs (single session, idle):
| Tool | Footprint | Peak | Language |
|-------------|-----------|--------|---------------|
| Codex | 15 MB | 15 MB | Rust |
| OpenCode | 130 MB | 130 MB | Go |
| Claude Code | 360 MB | 746 MB | Node.js/React |
vmmap shows Claude Code reserves 32.8 GB virtual memory just for the V8 heap, has 45% malloc fragmentation, and a peak footprint of 746 MB that never gets released, classic leak pattern.
On my 16 GB Mac, a "normal" workload (2 Claude sessions + browser + terminal) pushes me into 9.5 GB swap within hours. My laptop genuinely runs slower with Claude Code than when I'm running local LLMs.
I get that shipping fast matters, but building a CLI with React and a full Node.js runtime is an architectural choice with consequences. Codex proves this can be done in 15 MB. Every Claude Code session costs me 360+ MB, and with MCP servers spawning per session, it multiplies fast.
Replies
I believe they use https://bun.com/ Not Node.js
OpenCode is not written in Go. It's TS on Bun, with OpenTUI underneath which is written in Zig.
why do you care about uncommitted virtual memory? that's practically infinite
Jarred Sumner (bun creator, bun was recently acquired by Anthropic) has been working exclusively on bringing down memory leaks and improving performance in CC the last couple weeks. He's been tweeting his progress.
This is just regular tech debt that happens from building something to $1bn in revenue as fast as you possibly can, optimize later.
They're optimizing now. I'm sure they'll have it under control in no time.
CC is an incredible product (so is codex but I use CC more). Yes, lately it's gotten bloated, but the value it provides makes it bearable until they fix it in short time.