Approach Comparison#

The journey#

Every approach we evaluated was an attempt to solve the same core problem: generate unique IDs across multiple servers without coordination. Each one fixed a previous problem but introduced a new one — until Snowflake solved them all.

Single server counter
  → works, but SPOF

Multiple servers with independent counters
  → SPOF fixed, but collisions

UUID
  → no coordination, no collisions, but not sortable + double storage + page splits

Ticket Server (Redis shared counter)
  → unique across servers, but Redis is a new SPOF + network hop per ID

Pre-Generated Key Pool (KGS)
  → no request-time coordination, crash-safe, but no embedded timestamp

Snowflake
  → unique, time-sortable, 64-bit, no coordination, no SPOF

Full comparison table#

Property	Single Counter	UUID v4	UUID v7	Ticket Server	Key Pool (KGS)	Snowflake
Globally unique	✅	✅ probabilistic	✅ probabilistic	✅	✅	✅ structural
Time-sortable	⚠️ order only	❌	✅	⚠️ order only	⚠️ order only	✅
Embedded timestamp	❌	❌	✅	❌	❌	✅
Storage	✅ 8 bytes	❌ 16 bytes	❌ 16 bytes	✅ 8 bytes	✅ 8 bytes	✅ 8 bytes
B+ tree performance	✅ sequential	❌ page splits	✅ sequential	✅ sequential	✅ sequential	✅ sequential
No SPOF	❌	✅	✅	❌ Redis	✅	✅
No coordination at request time	✅	✅	✅	❌ Redis call	✅ in-memory	✅
Crash-safe	❌ counter lost	✅	✅	✅	⚠️ gaps on crash	✅

When to use what#

UUID v4 — when you need zero infrastructure, zero coordination, and don't care about sortability or storage. Quick prototypes, non-critical systems, systems where IDs are never used for ordering.

UUID v7 — when you need zero coordination but also want time-sortability. Modern systems that can afford 16-byte IDs. A strong choice when you want simplicity without the page split problem.

Ticket Server — when simplicity matters more than availability. Small-scale internal systems where Redis downtime is acceptable or Redis is already highly available in your infrastructure.

Pre-Generated Key Pool — when you want coordination-free request serving and can tolerate gaps on crash. Works well for systems that pre-warm their key cache on startup.

Snowflake — when you need everything: uniqueness, time-sortability, 64-bit, no SPOF, no coordination at request time, and an embedded timestamp. The right choice for any large-scale system. Used by Twitter, Discord, Instagram, and most major platforms.

Interview framing

In an interview, walk through the evolution — don't jump straight to Snowflake. Show that you understand why each simpler approach fails, and that Snowflake is the answer because it systematically eliminates every failure mode. That reasoning is what separates a strong answer from a name-drop.