“An LRU cache for your friend group. Twelve slots, kept warm. Adding a new friend evicts the least recently used one to cold storage (LinkedIn). Sorry, Greg — you haven’t been accessed since 2019.”
The Problem
Your address book has 1,847 contacts. Working set: nine. The rest are cold pages occupying RAM you do not have. Every Friday at 7pm, your brain thrashes — swapping in Brendan from grad school for a half-second so it can swap him right back out. Cache full, nothing being served, fan spinning audibly.
The Solution
Twelve warm slots. Strict LRU. A new friend evicts the bottom of the stack. Re-accessing a cold friend (one earnest text plus three hangouts in 60 days) promotes them back to warm — at the cost of evicting whoever is now at the bottom. Nature is brutal. Engineers, more so.
CACHE STATE · warm tier · 12 / 12 slots
tenant: you0x02
Ash
last: yesterday
hot
0x03
Priya
last: 3 days
warm
0x04
Tasha
last: 5 days
warm
0x05
Marcus
last: 8 days
warm
0x06
Jules
last: 12 days
cooling
0x07
Sam
last: 19 days
cooling
0x08
Robin
last: 26 days
cooling
0x09
Theo
last: 31 days
stale
0x0A
Bea
last: 44 days
stale
0x0B
Greg
last: 5y 2mo
LRU ← next out
hit rate (30d): 71%Greg expires on next insert
The Eviction Event
You meet someone at a wedding. Their name is Mateo. He is funny. The cache must make room.
incoming
Mateo
met at: cousin’s wedding
→
cache (warm)
12 / 12 full
policy: strict LRU
⤓
evicted
Greg
→ cold storage (LinkedIn)
evicted_at: 2026-06-24T22:47:03Z · reason: LRU · ttl_in_cold: ∞
Eviction Policy Comparison
LRULeast Recently UsedDefault. Greg goes first because Greg has not been Used.
LFULeast Frequently UsedEvicts the friend you only see once a year. Sorry, dad.
FIFOFirst In, First OutChildhood friends evicted first. Brutal but legible.
MRUMost Recently UsedEvicts whoever you just hung out with. For commitment-phobes.
ARCAdaptiveWatches you, learns. Evicts the friend you secretly resent.
ANXAnxiety-drivenEvicts the one you owe a text. Cache is now empty. You feel worse.
Hit Rate by Query
Real production data from beta tenants. The cache is well-tuned for brunch and emotionally illiterate for moving day.
“can you read this draft”
42%
“help me move Saturday”
3%
Pricing
$0
12 slots, strict LRU. Eviction notice delivered to the evicted party (“hey, no thoughts on you specifically”).
$11 / mo
48 slots, ARC. Cold-storage indexed for fast re-warm. One ghost-recovery per quarter (“sorry just seeing this”).
talk to sales
Tiered cache. Hot/warm/cold/archival. Dedicated cache admin (your assistant). Custom policy: ANX, MRU, or “whatever mom thinks.”
TAM
Friendships unnecessarily kept warm (global)
2.8B adults × 1,800 cold contacts × $11 ARPU
= a number we evicted
Greg, if you’re reading this on LinkedIn: hi.
The Ask
$4.5M seed. Builds: a Dunbar-aware eviction engine, a kind-letter generator for evicted parties (“you’re still important to me, just paged out”), and a re-warm API that lets you promote a cold friend at the cost of one warm one — with a diff so you can see, in writing, who you traded.
Series A pitch:“We’re Redis, but for people who keep saying ‘we should get coffee.’”