prmt: instant-feeling shell prompts (sub-millisecond, even over SSH)

Ivan Zakharchanka — Wed, 29 Oct 2025 22:06:45 +0000

TL;DR: Rust-powered shell prompt with sub-millisecond rendering that stays fast over SSH.

3axap4eHko / prmt

Ultra-fast, customizable shell prompt generator

prmt 🚀

Ultra-fast, customizable shell prompt that won't slow you down

Rendered with "{path:#89dceb}{rust:#f38ba8:f: 🦀}{git:#f9e2af:f: }\n{ok:#a6e3a1}{fail:#f38ba8} "

Features

⚡ Blazing Fast: Sub-millisecond rendering for typical prompts (~2ms end-to-end)
🎨 Highly Customizable: Full control over colors, formats, and what information to show
🚀 Context Aware: Automatically detects git repos, project files, shows only what's relevant
📦 Zero Dependencies: Single binary, no runtime dependencies required
🦀 Memory Efficient: Zero-copy parsing with SIMD optimizations
✨ Smart Rendering: Only shows information when relevant to your current directory

Why prmt?

Faster than alternatives – Typical prompts render in ~2ms. Starship averages 10-50ms, oh-my-posh 20-100ms.

Zero configuration needed – Works out of the box with sensible defaults. Customize only what you want.

Predictable performance – No async operations, no network calls, no surprises. Your prompt is always instant.

Single binary – Just install and go. No configuration files required unless…

View on GitHub

The problem

Starship: Beautiful but slow (~10-50ms renders). Async I/O adds unpredictable latency over SSH.

oh-my-posh: Feature-rich but heavy. 20MB binary, 20-100ms renders.

Pure Bash/Zsh: Fast but unmaintainable config spaghetti.

Why prmt?

Sub-millisecond renders — ~10-50 µs for path + git
Predictable — no async I/O, no surprises over SSH
Zero config — works out of the box
Drop-in replacement — migrate from Starship in 5 minutes

Setup

cargo install prmt

Bash / Zsh

# Bash: ~/.bashrc
PS1='$(prmt --code $? "{path:cyan:s} {git:purple:s:on :} {ok:green}{fail:red} ")'

# Zsh: ~/.zshrc (add this line first)
setopt PROMPT_SUBST
PROMPT='$(prmt --code $? "{path:cyan:s} {git:purple:s:on :} {ok:green}{fail:red} ")'

Fish

# ~/.config/fish/config.fish
function fish_prompt
  prmt --code $status '{path:cyan:s} {git:purple:s:on :} {ok:green}{fail:red} '
end

PowerShell is also supported — see the README.

Performance breakdown

Prompt	Modules	Time	What's slow?
Minimal	`{path}`	~10 µs	Nothing
Typical	`{path} {git} {ok}{fail}`	~1-2 ms	Git status check
Full	`{path} {git} {rust} {node}`	~25-30 ms	Running `rustc --version` etc
Fast mode	`--no-version`	< 5 ms	Skips all version calls

Key insight: The renderer is microseconds. Version detection (running rustc --version, node --version) dominates total time. Use --no-version if you don't need versions.

Reproduce locally

# Internal benchmark
prmt --bench '{path} {git} {ok}{fail}'

# End-to-end with hyperfine
hyperfine --warmup 5 'prmt --no-version "{path} {git} {ok}{fail}"'

Migrating from Starship

Starship	prmt
`directory`	`{path:r}` (relative) or `{path:s}` (short)
`git_branch`	`{git:s}` (branch only)
`git_status`	`{git}` (branch + status)
`character`	`{ok}{fail}` with `--code $?`
`nodejs`	`{node:s}` (short version)
`rust`	`{rust:s}` (short version)

Plain prompt (path + git + indicator):

prmt --code $? "{path:cyan:s} {git:purple:s:on :} {ok:green}{fail:red} "

With versions (add Node/Rust):

prmt --code $? "{path:cyan:s} {node:green:s: ⬢}{rust:red:s: 🦀}{git:purple} {ok}{fail} "

Output: projects ⬢20.5 🦀1.90 main ❯

Why it's fast

Zero-copy parsing — minimal allocations
Cached module detection — only checks relevant directories
No async runtime — no Tokio overhead, predictable latency

See the README for benchmarks and implementation details.

Format cheatsheet

Syntax: {module:style:type:prefix:postfix}

Modules: path, git, rust, node, python, go, time, ok, fail

Styles: red, cyan, #89dceb (hex), bold, dim, italic

Path types: r (relative), a (absolute), s (short — last dir only)

Git types: f (branch+status), s (branch only)

Version types: m (major), s (short), f (full)

Examples:

{path:cyan:s}              # Short path in cyan
{git:purple::on :}         # "on main" in purple
{rust:red:s: 🦀}           # "🦀1.90" in red
{ok:green:✓}{fail:red:✗}  # Custom success/fail symbols

Full reference in the README.

Try it

cargo install prmt

Like it? ⭐ the repo and share your config!

Ivan Zakharchanka · GitHub @3axap4eHko

DEV Community: Ivan Zakharchanka

prmt: instant-feeling shell prompts (sub-millisecond, even over SSH)

3axap4eHko / prmt

Ultra-fast, customizable shell prompt generator

prmt 🚀

Features

Why prmt?

The problem

Why prmt?

Setup

Bash / Zsh

Fish

Performance breakdown

Reproduce locally

Migrating from Starship

Why it's fast

Format cheatsheet

Try it