HarperDB
Distributed edge database combining SQL and NoSQL in a single JSON-native system with built-in replication and custom functions.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
TLS must be configured separately — not enabled by default in self-hosted deployment.
⚡ Reliability
Best When
Best for edge deployments needing SQL + NoSQL flexibility with built-in replication and low-latency data access.
Avoid When
Avoid when standard PostgreSQL ecosystem compatibility is required or when managed cloud service is mandatory.
Use Cases
- • Deploy database logic at edge locations for low-latency agent data access globally
- • Run SQL queries over schema-less JSON documents without predefined schemas
- • Build real-time pub/sub event streams using HarperDB's native messaging layer
- • Execute custom application logic as serverless functions collocated with data
- • Implement multi-region data replication for globally distributed agent pipelines
Not For
- • Workloads requiring PostgreSQL/MySQL ecosystem compatibility and tooling
- • Large-scale OLAP analytics requiring columnar storage optimization
- • Teams needing a fully managed cloud service with enterprise SLA without self-hosting
Interface
Authentication
HTTP Basic auth or API tokens. Role-based access control with super_user, cluster_user, and custom roles.
Pricing
HarperDB Cloud (managed) has usage-based pricing. Self-hosted free for development.
Agent Metadata
Known Gotchas
- ⚠ All REST API operations use POST with operation field in JSON body — there are no distinct HTTP methods per operation type
- ⚠ hash_attribute (primary key) must be defined at table creation — records without hash_attribute get auto-generated UUIDs
- ⚠ SQL queries go through the same POST endpoint as NoSQL operations — use sql operation type, not a separate SQL endpoint
- ⚠ Custom Functions run in Node.js collocated with DB — function deployment restarts the custom functions server, causing brief downtime
- ⚠ Replication setup requires clustering license — single-node free tier cannot replicate to other HarperDB instances
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for HarperDB.
Scores are editorial opinions as of 2026-03-06.