Choose a Backend

stet supports four storage backends. The backend is selected automatically from the file extension you pass to store=.

CSV (`.csv`)

The default. Human-readable, easy to inspect in a spreadsheet.

@stet.once(store='_stet_store.csv')
def run(alpha, beta): ...

Use when: You want to inspect or edit records manually, or share the store with non-Python tools.

Pure Python, no extra dependencies beyond filelock.

@stet.once(store='_stet_store.json')
def run(alpha, beta): ...

Use when: You want a dependency-free, human-readable format.

Robust, concurrent-friendly, query-able with standard SQL tools.

@stet.once(store='_stet_store.sqlite')
def run(alpha, beta): ...

Use when: You have many thousands of records, need fast lookups, or want to query the store with SQL.

Requires stet[parquet]. Compact binary format, fast for large datasets.

$ uv add stet[parquet]

or

$ python -m pip install stet[parquet]

@stet.once(store='_stet_store.parquet')
def run(alpha, beta): ...

Use when: You have very large stores and want the smallest file size with fast reads.

Format	Inspect with	Extra install	Fast for large stores
CSV	Any text editor	-	No
JSON	Any text editor	-	No
SQLite	DB browser / sqlite3 CLI	-	Yes
Parquet	pandas / DuckDB	`stet[parquet]`	Yes