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v0.2.0 — Open Source

Sluggish60fps$25/mo$03 secinstant

Mercury is a native API client written in Rust. No Electron bloat. No cloud accounts. No subscription fees. Just ⌘+Enter and your request is sent.

60fps
Native UI
<300ms
Startup
<16ms
Input Lag
$0
Forever
Mercury App - 3-column layout showing sidebar, request editor, and response panel
// The Philosophy

We said no to everything
that doesn't matter

While Postman adds AI assistants, team collaboration, and 47 features you'll never use, we built the opposite. Mercury does one thing: send HTTP requests. Fast.

Inspired by 37signals and the Unix philosophy. No accounts. No cloud. No tracking. No bloat. Your data stays on your machine, in plain text files you can grep.

Native Performance

GPU-accelerated 60fps rendering. <16ms input latency. Scrolling that feels like butter. This is what native means.

📁

Files, Not Databases

Live Two-Way Sync. Edit in VS Code, run in Mercury. Change a file, it updates instantly. No import/export.

🔒

Truly Local

We don't have servers. We can't see your API keys even if we wanted to. Your secrets stay yours.

⌨️

Keyboard First

⌘+Enter to send. ⌘+S to save. ⌘+K to search. Your hands stay on the keyboard where they belong.

The honest comparison

Numbers don't lie. Marketing does.

Postman
Insomnia
Mercury
Startup Time
3-5 seconds
2-4 seconds
<300ms
UI Frame Rate
Sluggish
Variable
60fps native
Input Latency
50-100ms
30-50ms
<16ms
App Size
~500MB
~400MB
6MB
Price (Pro)
$14-25/mo
$5-18/mo
Free forever
Account Required
Yes
Yes
No
Open Source
No
Partially
100%
Telemetry
Yes
Yes
None
Works Offline
Limited
Limited
Always

Your requests. Your files.

No proprietary databases. Just plain text you can version control.

# ~/api-tests/users/get-user.json

GET https://api.example.com/users/{{user_id}}
Authorization: Bearer {{token}}
Accept: application/json

# Variables loaded from .env files. Git-friendly. Greppable.

Get Mercury

One download. No signup. No credit card.

Quick Install (macOS / Linux):
curl --proto '=https' --tlsv1.2 -LsSf https://github.com/Harry-kp/mercury/releases/latest/download/mercury-installer.sh | sh

Windows (PowerShell):
irm https://github.com/Harry-kp/mercury/releases/latest/download/mercury-installer.ps1 | iex

Then run: mercuryWant it in your Applications folder?