Blog on ⎨ Saurabh Kumar ⎬

How I Optimized My Zsh Startup Time

Mon, 11 May 2026 00:00:00 +0000

My zsh prompt was taking close to a second on a fresh terminal. Not catastrophic, but you feel it every time tmux spawns a new pane, which for me is constantly. The config had been growing for years and nobody had been auditing it.

What follows is the audit, and the eight things I changed.

Measure first

# Cold-start benchmark (run a few times, watch the variance):
for i in {1..5}; do time zsh -i -c exit; done

# In-shell flamegraph:
# 1. Uncomment `zmodload zsh/zprof` at the top of .zshrc
# 2. Add `zprof` at the bottom
# 3. Open a new shell
zprof | head -40

zprof is the one that helped most. It prints which function calls and evals are burning time, sorted by self-time and call count.

The Great Fork: How Redis Lost Its Soul and Valkey Found It

Mon, 12 Jan 2026 00:00:00 +0000

The Moment Everything Changed

Picture this: It’s March 2024, and somewhere in a conference room, executives at Redis Inc. are making a decision. They’re looking at their balance sheets, watching cloud giants like AWS and Google profit from offering managed Redis services, and they’re thinking: This isn’t fair. We built this. Why are they making all the money?

So they pull the trigger. On March 20, 2024, after fifteen years of operating under the BSD 3-clause license—one of the most permissive licenses in open source—they announce a switch to dual source-available licensing: RSALv2 and SSPLv1. The new licensing takes effect with Redis 7.4. The message is simple: you can still see our code, but if you want to build a business with it, we need our cut.

Default Apps 2025

Wed, 05 Nov 2025 00:00:00 +0000

“Apps I’ve been using regularly this year.” Heavily inspired by Jeff Triplett. Catalogued by Robb Knight’s App Defaults

Mail Client: Edison Mail and gmail in browser
Notes: Obsidian, SimpleNotes
To-Do: Bullet Journel
Photo Shooting: iPhone, Canon 6D
Photo Editing: PhotoShop, Gimp
Calendar: Notion Calendar
Cloud File Storage: iCloud + Google Drive
RSS: NetNewsWire
Contacts: Apple Contacts & Google Contacts
Browser: Arc, Zen Browser and Safari
Chat: Apple Messages, Discord, Slack
Bookmarks: RainDrop.io
Read It Later: Safari Reading List
Word Processing: Apple Pages
Spreadsheets: Google Sheets
Presentations: Figma
Shopping Lists: Amazon
Budgeting and Personal Finance: paisa
News: Perplexity.ai, NetNewsWire
Music: Youtube Music
Password Management: 1Password and Apple Passwords
Code Editor: Zed & Cursor
VPN: AdGuard, Zscalar

Bonus Items

Important enough to include here, ordered roughly by how often I rely on each.

Notes on Understanding Hebbian Learning

Wed, 05 Nov 2025 00:00:00 +0000

Dive into Hebbian learning, the fundamental principle of how our brains learn and form memories. From Pavlov’s dogs to your morning coffee ritual, discover how neurons wire together through repetition.

Cut Django Database Latency by 50-70ms With Native Connection Pooling

Wed, 18 Jun 2025 00:00:00 +0000

Your Django app is hemorrhaging database resources. Each HTTP request creates and destroys expensive PostgreSQL connections, adding 50-70ms of latency your users feel directly. This connection overhead costs you real money in cloud environments where database CPU time translates to monthly bills.

Django 5.1 (released August 7, 2024) eliminated this waste with native connection pooling¹. Deploy the fix in under 10 minutes and watch your database connection overhead drop by 60-80% while your response times improve by 10-30%.

Thoughts on Astral's ty: The Lightning-Fast Python Type Checker & Language Server

Fri, 09 May 2025 00:00:00 +0000

Python developers have long suffered from painfully slow type checkers. Running mypy on a large codebase? Time to grab a coffee. Need real-time type checking in your editor? Prepare for frustrating lag and occasional crashes. But what if type checking could be nearly instantaneous?

Enter ty (gh:astral-sh/ty), the latest tool from Astral—the team behind the wildly successful Ruff linter and uv package manager. Still in pre-alpha, ty is already turning heads with performance that makes existing solutions look like they’re running in slow motion.

Handling Django Authentication Redirects in HTMX Applications

Fri, 02 May 2025 00:00:00 +0000

Ever been in the middle of building a slick Django app with HTMX when you hit that authentication headache? You know the one - a user’s session times out, they click something, and instead of getting a proper login page, they get a weird login form fragment jammed into whatever DOM element was being updated. Not exactly the seamless experience we’re going for!

I ran into this problem recently and thought, “There’s got to be a better way.” Spoiler alert: there is! Let me show you a simple middleware solution that makes this authentication dance much smoother.

Efficiently Managing Mass URL Redirects with Nginx

Mon, 25 Sep 2017 00:00:00 +0000

In this post, I’ll show you how to efficiently implement hundreds or even thousands of URL redirects on your server without sacrificing performance. We’ll use Nginx’s powerful map module which creates optimized hash tables for fast lookups.

Creating Your Redirect Configuration

First, create a file called redirects-map.conf where each line represents a single redirect rule in this format:

<old_location> <new_url>;

You can use two types of location specifications:

Simple path redirects: