Consul KV
activeby HashiCorp (IBM) · since 2014 · also known as HashiCorp Consul, Consul
The key-value store built into HashiCorp Consul for service config, locks and discovery.
Overview
Consul KV is the hierarchical key-value store that ships inside every Consul server cluster, replicated with Raft and exposed over HTTP and DNS alongside Consul's service discovery and service mesh. It is commonly used for dynamic application configuration, feature flags, sessions-based locks and leader election, often with consul-template or Vault on top. HashiCorp moved Consul to the Business Source License in 2023 and is now owned by IBM (acquisition completed February 2025). Use it when you already run Consul; on its own it is a convenience store, not a database.
Strengths & trade-offs
Strengths
- +Ships with Consul: no extra system if you already use it for discovery or mesh
- +Blocking queries and watches for change notification
- +Sessions provide locks and leader election
- +ACLs and integration with Vault and consul-template
Trade-offs
- −512 KB value limit and small total dataset by design
- −BSL license restricts competing commercial use
- −No cross-datacenter KV replication out of the box
- −Coupled to Consul's release cadence and operational model
Great for
- +Dynamic configuration for services in a Consul mesh
- +Feature flags rendered via consul-template
- +Distributed locks and leader election
Think twice for
- −Application data storage
- −Large values or datasets
- −Organisations that require an OSI open-source license
Capabilities
Native or official first-party support · 4 of 25 tracked
Scale & consistency
- Comfortable data size
- Small · ≤ 100 GB
- Horizontal scaling
- None
- Multi-region
- No
- Transactions
- Limited ACID
- Consistency
- Strong, Eventual
- Schema
- Schemaless
- Architecture
- Distributed, Client server
- Query languages
- Consul HTTP API
KV data is per datacenter and fully replicated across 3-5 servers; cross-datacenter KV needs external replication tooling.
Deployment
Ecosystem
Alternatives to Consul KV
Raft-based, strongly consistent key-value store that holds Kubernetes' cluster state.
hashicorp-consul-kv vs etcd →The original coordination service: hierarchical znodes, watches and ephemeral nodes for clusters.
hashicorp-consul-kv vs apache-zookeeper →Vercel's globally replicated read-optimized config store (renamed Global Config in 2026).
hashicorp-consul-kv vs vercel-edge-config →Globally cached, eventually consistent key-value store for read-heavy data at Cloudflare's edge.
hashicorp-consul-kv vs cloudflare-workers-kv →etcd's maintained fork of BoltDB: a simple, pure-Go B+tree store in a single file.
hashicorp-consul-kv vs bbolt →D. J. Bernstein's constant database: immutable on-disk hash tables with two-read lookups and atomic swaps.
hashicorp-consul-kv vs cdb →Consul KV FAQ
What is Consul KV?
Consul KV is a key-value database by HashiCorp (IBM), first released in 2014. Consul KV is the hierarchical key-value store that ships inside every Consul server cluster, replicated with Raft and exposed over HTTP and DNS alongside Consul's service discovery and service mesh. It is commonly used for dynamic application configuration, feature flags, sessions-based locks and leader election, often with consul-template or Vault on top. HashiCorp moved Consul to the Business Source License in 2023 and is now owned by IBM (acquisition completed February 2025). Use it when you already run Consul; on its own it is a convenience store, not a database.
Is Consul KV open source?
Not in the OSI sense. Consul KV is source-available: you can read the code, but the license restricts some uses, typically offering it as a competing managed service. License: Business Source License 1.1.
Does Consul KV support ACID transactions?
Partly. Consul KV offers limited ACID guarantees (for example, single-record or single-partition transactions), with strong, eventual consistency.
Does Consul KV scale horizontally?
Consul KV does not scale horizontally; it runs on a single node, so you scale it up rather than out. It is comfortable at small scale (≤ 100 GB).
How can I run Consul KV?
You can self-host it.
What is Consul KV best for?
Consul KV is a strong fit for dynamic configuration for services in a Consul mesh; feature flags rendered via consul-template; and distributed locks and leader election. Think twice for application data storage.
What are the best alternatives to Consul KV?
Common alternatives to Consul KV include etcd, Apache ZooKeeper, Vercel Edge Config, Cloudflare Workers KV and bbolt. The right choice depends on your workload, scale and hosting; WhichDB's smart match ranks them against your requirements.
How popular is Consul KV?
Consul KV ranks #49 of 844 databases on the WhichDB Score (39.0/100), and #8 among key-value databases. The score combines public adoption signals such as package downloads, GitHub activity, job posts and developer discussion.