ScyllaDB API
Apache Cassandra-compatible NoSQL wide-column database written in C++ delivering sub-millisecond p99 latency and 10x Cassandra throughput, with a REST API for administration and the native Cassandra CQL protocol for data operations.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
TLS available for client-to-node and inter-node communication but requires manual configuration on self-hosted installs. ScyllaDB Cloud enforces TLS. Authentication via username/password with SASL. Enterprise adds LDAP and Kerberos. AGPL v3 license source transparency supports dependency hygiene review.
⚡ Reliability
Best When
You need Cassandra-compatible wide-column storage at much lower latency and higher throughput than Apache Cassandra, especially for time-series or high-cardinality workloads requiring horizontal scale.
Avoid When
Your team lacks Cassandra data modeling experience, your data model requires ad-hoc querying with flexible filtering, or your scale does not justify the operational complexity.
Use Cases
- • High-throughput agent event storage where Cassandra API compatibility is needed but Cassandra latency is too high
- • Time-series sensor and IoT data at massive scale with predictable single-digit millisecond read latency
- • User profile and session storage for real-time personalization agents requiring consistent low-latency reads
- • Leaderboard and counter workloads leveraging Cassandra's distributed counter column type
- • Agent state persistence at scale where horizontal partitioning across many nodes is required
Not For
- • Relational data with complex JOIN requirements — ScyllaDB is not a relational database
- • Teams without Cassandra data modeling expertise — partition key design is critical and non-obvious
- • Small-scale applications where PostgreSQL or DynamoDB would be simpler to operate
Interface
Authentication
Authentication uses Cassandra-compatible SASL/username-password over the CQL protocol. ScyllaDB Enterprise adds LDAP, Kerberos, and role-based authorization (system_auth keyspace). ScyllaDB Cloud uses API keys for the management plane and standard CQL auth for data plane connections. Authorization at keyspace, table, and operation level via Cassandra GRANT syntax.
Pricing
Open source community edition is free under AGPL v3. ScyllaDB Enterprise adds proprietary features (incremental compaction, advanced security). ScyllaDB Cloud is the managed offering. Serverless tier (in preview) provides elastic scaling with consumption-based pricing.
Agent Metadata
Known Gotchas
- ⚠ Data model must be designed around query patterns — table-per-query is standard; agents that try to add filters on non-partition-key columns will fail or cause full-table scans
- ⚠ Consistency level tuning is required for agent workloads — QUORUM provides the right balance but agents often default to ONE which can return stale data
- ⚠ Cassandra's CQL ALLOW FILTERING is a trap — it enables full scans that can take minutes on large datasets; agents should never use it in production queries
- ⚠ Counter columns cannot be mixed with regular columns in the same table — a frequent schema design mistake
- ⚠ ScyllaDB's shard-per-core architecture means connection pooling should target all shards — drivers must be configured for topology-aware load balancing
- ⚠ TTL (time to live) on rows does not immediately reclaim space — compaction must run to free disk space after expiry
- ⚠ Lightweight transactions (LWT/IF conditions) have much higher latency than regular writes due to Paxos consensus — avoid in hot paths
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for ScyllaDB API.
Scores are editorial opinions as of 2026-03-06.