StrataDB provides six data primitives — purpose-built data structures that cover the state management needs of AI agents. Each primitive has a specific shape and API, rather than forcing everything into a generic key-value model.
The Six Primitives
| Primitive | Shape | Best For |
|---|---|---|
| KV Store | Key → Value | Working memory, config, scratchpads |
| Event Log | Append-only sequence of typed events | Audit trails, tool call history, decision logs |
| State Cell | Named cell with CAS | Coordination, counters, locks, state machines |
| JSON Store | Key → JSON document with path access | Structured config, conversation history |
| Vector Store | Collection of keyed embeddings with pluggable indexing (brute-force or HNSW) | Similarity search, RAG context, agent memory |
| Branch | Named isolated namespace | Session isolation, experiments, multi-tenancy |
Choosing the Right Primitive
“I need to store a simple value by key” → KV Store
“I need an immutable log of events” → Event Log. Events are append-only. You cannot modify or delete individual events.
“I need a value that multiple writers coordinate on” → State Cell. The compare-and-swap (CAS) operation lets you update only if you have the latest version, preventing lost updates.
“I need a structured document I can update at specific paths” → JSON Store. You can read and write at JSON paths like $.config.temperature without replacing the whole document.
“I need to store and search embeddings” → Vector Store. Create collections with a fixed dimension and distance metric, then search by similarity. Supports brute-force (exact) and HNSW (approximate) indexing, batch upsert for bulk loading, and 8 metadata filter operators.
“I need to isolate data between sessions or experiments” → Branches. Every other primitive is scoped to a branch.
Comparison
| Feature | KV | Event | State | JSON | Vector |
|---|---|---|---|---|---|
| Read by key | Yes | By sequence | By cell name | By key + path | By collection + key |
| Write | Put (overwrite) | Append only | Set / CAS | Set at path | Upsert |
| Delete | Yes | No | No | Yes | Yes |
| List/scan | By prefix | By type | No | By prefix | By collection |
| Search | No | No | No | No | Similarity |
| Versioned | Yes | Yes (sequence) | Yes (counter) | Yes | Yes |
| Transactional | Yes | Yes | Yes | Yes | No* |
*Vector operations are not transactional — they bypass the session transaction system.
All Primitives Are Branch-Scoped
Every primitive is isolated by the current branch. Data written in one branch is invisible from another. See Branches for details.
Space Organization Within Branches
Within a branch, primitives are further organized by space. Each space has its own independent instance of every primitive. The default space is implicit — all operations target it unless you switch spaces.
$ strata --cache
strata:default/default> kv put key default-value
(version) 1
strata:default/default> use default experiments
strata:default/experiments> kv get key
(nil)Spaces are organizational, not isolation boundaries. Transactions can span multiple spaces within the same branch. See Spaces for the full guide.
All Primitives Use Value
The CLI auto-detects types from input format. Strings, integers, floats, and booleans are recognized automatically. JSON objects and arrays can be passed as JSON strings.
Next
- Value Types — the 8-variant type system
- Guides — per-primitive API walkthroughs