Hacker News
Arc, flat files, and the legendary single box
Hacker News runs on Paul Graham’s Arc dialect with data in files and memory — not a fleet of managed services. For years the whole forum lived on one server (plus failover), and staff comments still treat that simplicity as a feature.
2007–2008
Arc as MVP, filesystem as database
Single server
Arc (Racket)
Flat files / s-expressions
In-memory tables
HN started as a proving ground for Arc — Graham’s Lisp dialect — with stories and comments stored as Arc tables persisted to files, not Postgres. Early source mirrors on GitHub show monotonic IDs and comment trees written straight to disk.
Ask-HN threads from veterans describe the whole app as one process on one core talking to the filesystem. Unorthodox, yes. Expensive? Not remotely.
Lesson
If your queries are mostly “fetch this thread,” the filesystem is a database that already won.
2008–2018
One box, millions of pageviews
Primary + standby server
Arc
File-backed tables
Minimal caching layer
For a decade HN’s scaling story was folklore: one server, restart to fix certain bugs, flat files on ZFS. A 2022 HN thread (“HN ran on a single box in 2018 — has anything changed?”) references moderator dang confirming the setup was largely unchanged — still Arc, still austere.
Commenters doing back-of-napkin math on ~6M requests/day noted that well-tuned static-ish content on one modern machine is nowhere near hyperscaler territory — the magic was restraint, not spend.
Lesson
Most teams buy reliability with complexity before they need it. HN bought it with a spare box and disciplined code paths.
2019–today
Still lean, still file-shaped
Arc / proprietary HN fork
File-backed persistence
Small static infra footprint
HN’s production codebase stays proprietary, but public Arc distributions and mirrored early sources still show the design philosophy: fewer moving parts, accept restarts, optimize for moderator sanity.
The lesson for indie builders is not “copy Arc” — it’s that a read-heavy forum with sane caching does not require your cloud vendor’s entire catalog.
Lesson
Before you shard, ask whether your product is actually write-heavy or just socially noisy.
Sources
- Hacker News — Ask HN: server architecture thread (2021)
- Hacker News — “HN ran on a single box in 2018” thread (2022)
- GitHub — Early Hacker News Arc source mirror
Facts drawn from public engineering posts and interviews. Numbers are approximate where sources disagree — we're stack advisors, not historians.
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