What database does Discord use for trillions of chat messages?

Started with Cassandra, switched to ScyllaDB for speed at extreme scale.

ScyllaDB vs Cassandra: key differences?

ScyllaDB rewrites Cassandra in C++. Lower latency, higher throughput, same API. Drop-in often.

ScyllaDB or Cassandra for messages; Postgres for metadata. Hybrid rules.

☁️ Cloud & Databases

Billions of chat messages incoming. Postgres? It buckles. ScyllaDB laughs it off with a clever ring.

theAIcatchup Apr 08, 2026 3 min read

RDBMS like Postgres hit write bottlenecks at chat scale — sharding's a pain. 𝕏
ScyllaDB's ring topology and partition keys turn message floods into sequential reads. 𝕏
Hybrid setup: Postgres for relational data, Scylla for the message firehose. 𝕏

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#Cassandra #PostgreSQL #PostgreSQL sharding #ScyllaDB #chat app database #database scaling

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Originally reported by Dev.to