Strands Storage Backends¶

Community implementations of Strands' unified strands.storage.Storage interface — durable bytes-under-keys that back session snapshots, context offloading, memory stores, and anything else in the SDK that needs key/value persistence. This is a different, lower layer than the session managers: Storage is write / read / delete / list, with no notion of sessions or messages.

Storage vs. session vs. memory

Session managers (strands-session-*) implement SessionRepository — sessions, agent state, messages.
Storage backends (this page) implement strands.storage.Storage — opaque bytes.
Memory store (strands-dynamodb-store) implements MemoryStore — semantic recall.

The interface¶

class Storage(Protocol):
    async def write(self, key: str, data: bytes) -> None
    async def read(self, key: str) -> bytes | None
    async def delete(self, key: str) -> None
    async def list(self, prefix: str) -> list[str]   # full keys, sorted

The backends¶

Package	Backend	Install
`strands-sql-storage`	any SQLAlchemy DB	`pip install strands-sql-storage`
`strands-postgres-storage` · `strands-storage-postgres`	PostgreSQL	`pip install strands-postgres-storage`
`strands-mongodb-storage` · `strands-storage-mongodb`	MongoDB	`pip install strands-mongodb-storage`
`strands-storage-dynamodb`	Amazon DynamoDB	`pip install strands-storage-dynamodb`

Each backend is a thin adapter (~60 lines) — key normalization, then the four ops mapped onto the datastore, with blocking calls run in a thread so the async interface never blocks the event loop.

Usage¶

from strands.storage import Storage
from strands_postgres_storage import PostgresStorage   # or SQLStorage / MongoDBStorage / DynamoDBStorage

storage: Storage = PostgresStorage("postgresql://user:pass@localhost:5432/db")

await storage.write("sessions/abc/state.json", b"...bytes...")
data = await storage.read("sessions/abc/state.json")   # -> bytes | None
keys = await storage.list("sessions/")                 # sorted, prefix-matched
await storage.delete("sessions/abc/state.json")        # no-op if absent

Constructor cheatsheet:

PostgreSQL / SQLMongoDBDynamoDB

from strands_postgres_storage import PostgresStorage
PostgresStorage("postgresql://user:pass@host:5432/db")      # or engine=<Engine>
# any SQLAlchemy DB:
from strands_sql_storage import SQLStorage
SQLStorage("sqlite:///state.db")

from strands_mongodb_storage import MongoDBStorage
MongoDBStorage("mongodb://localhost:27017")

from strands_dynamodb_storage import DynamoDBStorage
DynamoDBStorage("strands_storage")   # table auto-created (PAY_PER_REQUEST)

Data model¶

Each backend stores one record per key with a namespaced prefix; list(prefix) is a prefix scan returning full keys, sorted. An optional prefix= on the constructor namespaces all keys (multi-tenant). Tested against real PostgreSQL, MongoDB, and DynamoDB.

License¶

MIT · part of the strands-agents-session family.