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Rubin Bhandari.
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The Iteration Log.

Practical guides on engineering, design, and the craft of building on the web for curious developers.

The JavaScript event loop, explained with a coffee shop
Featuredjavascript

The JavaScript event loop, explained with a coffee shop

One barista, two queues, and a rule about regulars. A mental model for how JavaScript handles one thing at a time without feeling slow.

Aug 11, 20262 min read
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The JavaScript event loop, explained with a coffee shopjavascript
Aug 11, 20262 min read

The JavaScript event loop, explained with a coffee shop

One barista, two queues, and a rule about regulars. A mental model for how JavaScript handles one thing at a time without feeling slow.

javascriptasync
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Idempotency keys: making API retries safearchitecture
Aug 8, 20263 min read

Idempotency keys: making API retries safe

The network will drop your request, the client will retry, and POST /payments will run twice. Idempotency keys are how you make 'try again' harmless.

apiarchitecture
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Graceful shutdowns: why your deploys drop requestsdevops
Aug 5, 20263 min read

Graceful shutdowns: why your deploys drop requests

SIGTERM arrives, the process dies mid-request, and users see 502s during every deploy. Graceful shutdown is the fix — here's how to do it right.

devopsdeployment
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JWT vs sessions: choosing the right auth for your APIauth
Aug 2, 20263 min read

JWT vs sessions: choosing the right auth for your API

Stateless tokens or server-side sessions? The answer depends on who's using your API — here's how to pick without cargo-culting either side.

authsecurity
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TypeScript's satisfies operator: type-safe without the ceremonytypescript
Aug 1, 20262 min read

TypeScript's satisfies operator: type-safe without the ceremony

You know that awkward dance between 'as' assertions and letting TypeScript infer everything? satisfies is the middle ground you've been missing.

typescripttypes
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Database connection pooling: why your DB is slow and your pool is emptydatabase
Jul 29, 20263 min read

Database connection pooling: why your DB is slow and your pool is empty

Opening a database connection is expensive. Connection pooling reuses them — and getting it wrong is how you end up with 'timeout waiting for connection' at 3pm.

databasenodejs
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