whichdb

Riak KV

active

by OpenRiak (Erlang Ecosystem Foundation) · since 2009 · also known as Riak, OpenRiak

Erlang-based, Dynamo-style key-value store built to stay up through ugly failures.

key-valuedatabase engineopen source (permissive)legacy
Website Docs Source★ 56 Compare Find similar

Overview

Riak KV is a masterless, Dynamo-inspired key-value database written in Erlang: consistent hashing spreads data over a ring, sloppy quorums and hinted handoff keep writes flowing through node failures, and active anti-entropy repairs divergence in the background. Basho, its creator, collapsed in 2017; bet365 bought the IP and open-sourced the enterprise replication features, and development now continues as OpenRiak in conjunction with the Erlang Ecosystem Foundation, with 3.4.x releases in 2026. It is still a solid choice for high-availability blob and record storage where you can live with eventual consistency, but its ecosystem is small compared to Cassandra or DynamoDB.

Transactional apps (OLTP)Session storeMetadata & configContent & catalogs

Strengths & trade-offs

Strengths

  • +Masterless ring keeps accepting writes during node and network failures
  • +Active anti-entropy and read repair heal replicas automatically
  • +Built-in CRDT data types (counters, sets, maps) for conflict-free merges
  • +Open-source multi-datacenter replication
  • +Erlang/OTP gives predictable behaviour under overload

Trade-offs

  • −Eventual consistency forces applications to handle siblings or use CRDTs
  • −Small community and few client libraries are actively maintained
  • −No rich query language; secondary indexes are basic
  • −Basho-era documentation and tooling are dated

Great for

  • +Highly available session and profile storage
  • +Healthcare or betting systems needing extreme uptime
  • +Object and blob metadata stores
  • +Shopping carts with CRDT merges

Think twice for

  • −Strongly consistent transactional workloads
  • −Ad-hoc querying and analytics
  • −Teams without Erlang operational experience

Capabilities

Native or official first-party support · 4 of 25 tracked

✓Secondary indexes
✓TTL / expiry
✓Durable persistence
✓Compression
–Transactions
–Joins
–Full-text search
–Vector search
–Geospatial
–JSON
–Change data capture
–Triggers
–Stored procedures
–Materialized views
–Pub/Sub
–Columnar storage
–In-memory
–Encryption at rest
–Role-based access
–Time travel
–Branching
–Online schema changes
–Streaming ingest
–Offline sync
–Runs in WebAssembly

Scale & consistency

Comfortable data size
Large · ≤ 1 PB
Horizontal scaling
Native
Multi-region
Active active
Transactions
None
Consistency
Eventual, Causal
Schema
Schemaless
Architecture
Distributed, Multi primary, Client server
Query languages
Riak HTTP API, Protocol Buffers API

Ring-based partitioning; multi-datacenter replication (formerly enterprise-only) is open source since 2.2.5/3.0.

Deployment

Self-hosted Vendor-managed cloud Serverless Embedded Edge Kubernetes operator

Ecosystem

apis & protocolsHTTP/REST, Protocol Buffers
client languagesErlang, Java, Python, Go, C#, Ruby, JavaScript
used bybet365, NHS England

Alternatives to Riak KV

Compare all→
Apache CassandraWide-Column55.9

Masterless wide-column database built for always-on writes across data centers.

riak-kv vs apache-cassandra →
ScyllaDBWide-Column45.9

C++ rewrite of Cassandra with shard-per-core design; also speaks the DynamoDB API.

riak-kv vs scylladb →
Amazon DynamoDBKey-Value63.3

AWS's serverless key-value and document store with single-digit-millisecond reads at any scale.

riak-kv vs amazon-dynamodb →
FoundationDBKey-Value36.8

Apple's ordered, strictly serializable distributed key-value store, built to have layers on top.

riak-kv vs foundationdb →
AerospikeKey-Value40.4

Flash-optimized distributed key-value and document database for predictable sub-millisecond latency at scale.

riak-kv vs aerospike →
TiKVKey-Value20.8

CNCF-graduated, Raft-replicated transactional key-value store in Rust; the storage layer of TiDB.

riak-kv vs tikv →

Riak KV FAQ

What is Riak KV?

Riak KV is a key-value database by OpenRiak (Erlang Ecosystem Foundation), first released in 2009. Riak KV is a masterless, Dynamo-inspired key-value database written in Erlang: consistent hashing spreads data over a ring, sloppy quorums and hinted handoff keep writes flowing through node failures, and active anti-entropy repairs divergence in the background. Basho, its creator, collapsed in 2017; bet365 bought the IP and open-sourced the enterprise replication features, and development now continues as OpenRiak in conjunction with the Erlang Ecosystem Foundation, with 3.4.x releases in 2026. It is still a solid choice for high-availability blob and record storage where you can live with eventual consistency, but its ecosystem is small compared to Cassandra or DynamoDB.

Is Riak KV open source?

Yes. Riak KV is open source. License: Apache License 2.0.

Does Riak KV support ACID transactions?

No. Riak KV does not provide ACID transactions; its consistency model is eventual, causal.

Does Riak KV scale horizontally?

Riak KV scales horizontally out of the box, with built-in sharding or partitioning. It is comfortable at large scale (≤ 1 PB). It supports active-active multi-region writes.

How can I run Riak KV?

You can self-host it.

What is Riak KV best for?

Riak KV is a strong fit for highly available session and profile storage; healthcare or betting systems needing extreme uptime; and object and blob metadata stores. Think twice for strongly consistent transactional workloads.

What are the best alternatives to Riak KV?

Common alternatives to Riak KV include Apache Cassandra, ScyllaDB, Amazon DynamoDB, FoundationDB and Aerospike. The right choice depends on your workload, scale and hosting; WhichDB's smart match ranks them against your requirements.

How popular is Riak KV?

Riak KV ranks #184 of 844 databases on the WhichDB Score (18.1/100), and #25 among key-value databases. The score combines public adoption signals such as package downloads, GitHub activity, job posts and developer discussion.