Ground fresh.
Think deep.
Writing on distributed systems, engineering culture, and the craft of building software — served through the lens of South Indian filter coffee.
Filter coffee is not instant. It is slow, deliberate, and demanding — ground fresh each morning, dripped through a steel percolator, served only when it is ready. That is the philosophy here. Every post starts from first principles. Every system design walks the trade-offs, not just the answers. Every idea is brewed until it is worth serving.
SMS privacy policy
What the messaging program collects, and the commitment that mobile numbers are never shared with third parties for marketing or promotional purposes.
SMS terms & conditions
Program description, message frequency, cost, and how to get help or stop. A single-recipient program: I am the only person it ever messages.
I Am the Filter Coffee Way
Seven principles. One ritual. One way of thinking. Grind fresh. Drip slow. Find the ratio. A philosophy for the craft of software, written in the language of Madras mornings.
URL Shortener, Brewed Slow
The full system design narrated — base62, Cassandra, layered cache. The reasoning behind every call.
Show Up Every Morning
On consistency as craft — why raising the floor matters more than chasing the ceiling.
CAP Theorem, Explained
Consistency, availability, partition tolerance — what you actually give up in practice, and when it matters.
B-tree vs LSM-tree
Two storage engine strategies, two different bets on the workload. What Postgres and Cassandra chose — and why.
The Junior Engineer's Blueprint
What to optimize for in years one through three. Hint: it is not the tech stack.
URL Shortener
TinyURL, bit.ly — the canonical read-heavy redirect. Single-counter ID generation, base62 encoding, layered caching, and a Cassandra-vs-Postgres call that depends entirely on traffic shape.
Paste Bin
Like URL shortener, but with content. Two-tier storage, inline vs. S3 split, expiry pipeline, and the moment object storage becomes the right answer.
Photo feed, fan-out on read vs write, and why your celebrity users break everything.
Twitter Timeline
Hybrid fan-out, timeline cache, the eventual consistency you live with so the home feed loads in time.
YouTube
Video chunks, ABR ladders, CDN economics, and where transcoding actually happens.
Persistent connections, presence, end-to-end encryption, and what "delivered" actually guarantees.
Uber
Geohashing, driver matching, and the cell-grid that makes "nearby" tractable.
Rate Limiter
Token bucket, sliding window, and where the limiter itself becomes the bottleneck.
Message Queue
Kafka-style logs, partitions, consumer groups, and the exactly-once myth.
Payments
Idempotency keys, two-phase commits, and the ledger that has to balance no matter what.
Caching strategies
Cache-aside, write-through, stampede protection, and the CDN edge. Where the cache lives changes everything downstream.
Token & ID generation
Base62, Snowflake, UUIDs, Zookeeper-coordinated ranges. Pick by collision tolerance, ordering, and coordination cost.
Database selection
Postgres vs Cassandra vs Redis — a decision framework that starts with access patterns, not popularity.
Latency
Throughput & sizes
The full system design roadmap
Every topic on the docket — what's published, what's drafting, and what's still just an interesting question. Updated as the notebook grows.