det

det stands for Data Engineering Tool — a fast, local-first SQL ETL workspace and pipeline orchestration engine powered by Apache DataFusion.

det is a modern data engineering toolkit that combines declarative SQL pipelines and YAML catalogs with the performance of the embedded Apache DataFusion vectorized execution engine.

Designed as a lightweight, zero-cloud-lock-in alternative to dbt, Spark, and heavyweight cloud orchestrators, det lets you ingest, transform, validate, and document complex multi-stage data pipelines directly on your filesystem.

Core Directives

The architecture of det is anchored on three non-negotiable core directives:

• 🧩 Modularity: Every component is decoupled and interchangeable. Data catalogs (catalog/*.yaml), pipeline DAG steps (pipelines/*/*.yaml), storage connectors (BaseConnector), DataFusion query execution, documentation generators, and the Web IDE operate as independent, composable building blocks following clean Medallion design (Bronze → Silver → Gold).

• ⚡ Performance: Built from the ground up on Apache DataFusion (Rust vectorized query engine) and Apache Arrow columnar memory. Pipeline stages run in-memory with multi-threaded SIMD parallelism, sub-second step execution, and zero cloud serialization overhead or network egress latency.

• 🔌 Extensibility: A first-class plugin architecture enables anyone to bring custom storage systems, databases (PostgreSQL, ClickHouse, DuckDB), cloud object stores (S3, GCS, Azure Blob), or REST APIs by subclassing BaseConnector. Drive pipelines headlessly via CLI, programmatically via Python SDK, or visually via the built-in browser IDE.

Key Highlights

• ⚡ Blazing Vectorized Compute: Powered by Apache DataFusion and Apache Arrow. Executes multi-threaded, SIMD-accelerated SQL transformations in-memory with sub-second latency across CPU cores.
• 📁 Polyglot Format Unification: Query and join across heterogeneous formats—Parquet, Delta Lake (ACID), CSV, JSON, NDJSON, multi-sheet Excel (.xlsx), XML, and Apache Iceberg—in pure ANSI SQL.
• 🔒 Zero Cloud Lock-In & Zero Egress: Transform gigabytes of data locally without provisioning Snowflake, BigQuery, Postgres, or cloud database clusters.
• 🌿 Git-Versionable by Default: Workspace catalogs, data connections, and pipeline steps are defined in clean YAML and SQL files. Branch, commit, review, and merge your data stack like application code.
• 🖥️ Headless First & Dual Mode:
  • Headless: Drive pipelines headlessly via CLI (det run) or Python SDK (det.Workspace) in CI/CD environments.
  • Interactive Web IDE: Launch the built-in browser UI (det gui) for visual DAG inspection, SQL editing, live previews, and telemetry monitoring.
• 📊 Automated Documentation & Lineage: Export static, standalone HTML and Markdown documentation portals complete with visual Mermaid DAG topology maps and column schemas.
• 🏪 Bundled Sample Warehouse: Instantly unpack NovaMart Global—a production-grade omnichannel enterprise warehouse with 14 connections, 8 file formats, and 10 multi-stage SQL pipelines.

Feature Comparison

Quick Start

Installation

Install via PyPI:

pip install det-core

Or install in editable mode from source:

git clone https://github.com/det-labs/det.git
cd det
pip install -e .

30-Second Walkthrough

1. Initialize a Workspace

Create a standard workspace directory structure:

det init my_workspace
cd my_workspace

2. Load the NovaMart Sample Warehouse

Unpack realistic omnichannel datasets, catalog connections, and 10 production SQL pipelines:

det sample-data

3. Execute Pipelines Headlessly

Run staging models, dimensional facts, and business data marts:

# Clean staging models
det run stg_customers_cleaned
det run stg_orders_normalized

# Build customer dimensions and facts
det run dim_customers
det run fct_orders

# Compute business intelligence mart
det run mart_customer_rfm_loyalty

4. Launch the Interactive Web IDE

Serve the visual workspace interface locally:

det gui --port 8765

Open your browser to http://127.0.0.1:8765 to visually explore catalogs, run SQL pipelines, inspect DAG topologies, and monitor execution metrics.

Architecture Overview

det organizes data transformations into clean, reproducible layers following the industry-standard Medallion Architecture:

[ Raw Sources ]
CSV • XML • JSON • NDJSON • Excel • Parquet • Delta Lake
         │
         ▼  (Bronze: Staging Layer)
  stg_customers_cleaned  •  stg_stores_catalog  •  stg_orders_normalized
         │
         ▼  (Silver: Intermediate Layer)
  dim_customers  •  dim_stores  •  fct_orders
         │
         ▼  (Gold: Analytical Marts)
  mart_customer_rfm_loyalty  •  mart_store_performance_vs_targets
         │
         ▼  (Published Destinations)
  Parquet Lakehouse  •  Delta Lake ACID  •  CSV Reports

Example: Multi-Format Vectorized SQL Join

det lets you join completely different file formats in a single SQL query without intermediate conversion:

-- Joining Silver Parquet transactions against an Excel financial quota sheet
WITH store_actuals AS (
  SELECT
    store_id,
    SUM(quantity * unit_price * (1.0 - discount_pct)) AS realized_revenue,
    COUNT(DISTINCT order_id) AS total_orders
  FROM fct_orders
  GROUP BY store_id
)
SELECT
  s.store_id,
  s.store_name,
  s.city,
  a.realized_revenue,
  t.target_q1_revenue AS target_revenue,
  ROUND((a.realized_revenue / t.target_q1_revenue) * 100, 2) AS quota_attainment_pct
FROM dim_stores s
JOIN store_actuals a ON s.store_id = a.store_id
JOIN financial_ref_targets t ON s.store_id = t.store_id
ORDER BY quota_attainment_pct DESC;

Workspace Structure

An initialized det workspace has a predictable, Git-friendly folder hierarchy:

my_workspace/
├── catalog/
│   └── default.yaml          # Declarative data sources & destinations
├── pipelines/
│   └── my_pipeline/
│       └── pipeline.yaml     # Multi-step SQL DAG definition
├── documentation/            # Generated HTML/Markdown lineage docs
├── extensions/
│   ├── connectors/           # Custom Python connector plugins
│   └── ui/                   # Custom UI extensions
├── logs/
│   └── pipelines/            # Execution run logs and metrics
└── source_data/              # Local data storage (optional)

Command Line Interface (CLI)

Python SDK

Integrate det directly into your Python automation, test suites, or Jupyter notebooks:

import det
from pathlib import Path

# Initialize workspace
workspace = det.Workspace("./my_workspace")

# Install sample data
det.sample_data.install(workspace.root)

# Execute pipeline programmatically
result = workspace.run_pipeline("Sample_Warehouse_Pipelines/mart_customer_rfm_loyalty")

print(f"Status: {result['status']}")
print(f"Execution Time: {result['duration_ms']:.2f} ms")
print(f"Rows Processed: {result['rows_processed']}")

Extensibility & Custom Connectors

det includes a plugin architecture based on the BaseConnector specification. Build and register custom storage backends (e.g. SQLite, PostgreSQL, REST APIs) in just a few lines of Python:

from det.connectors import BaseConnector, ConnectorRegistry

class SQLiteConnector(BaseConnector):
    guid = "my-custom-sqlite-connector"
    name = "SQLite Database"
    is_readable = True
    is_writable = True

    def scan(self, options, context, workspace):
        import sqlite3, pyarrow as pa
        conn = sqlite3.connect(options["path"])
        # Ingest into Arrow RecordBatch and register view
        ...
        return dataframe

# Register connector
ConnectorRegistry.register(SQLiteConnector())

Community & Contributing

We welcome contributions of all kinds! Whether you want to add a new connector, improve the DataFusion engine, enhance documentation, or report issues:

• 📖 Contributor Guide: Check out CONTRIBUTING.md for local setup, development guidelines, and our custom connector authoring tutorial.
• 🔌 Community Connector Wishlist: We are actively looking for contributors to help build and test connectors for:
  • Databases: PostgreSQL, ClickHouse, MySQL, DuckDB, Snowflake, BigQuery
  • Cloud Storage: AWS S3, Google Cloud Storage (GCS), Azure Blob Storage
  • Streams & APIs: Kafka / Redpanda, REST / Webhooks
• 💬 Join the Discussion: Have questions or pipeline architecture ideas? Join our GitHub Discussions.
• 📜 Code of Conduct: Review our Code of Conduct.
• 🛡️ Security: For security vulnerability reporting, please see SECURITY.md.

Running Tests

Run the test suite:

python -m unittest discover -s tests

Authors & License

Maintained by Saurabh Rai (saurabhr2@gmail.com) and det-Labs.

This project is licensed under the MIT License. Anyone is free to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the software, subject to including the copyright notice and attribution to the authors in all copies or substantial portions of the Software.

Discovery & Search Tags

ETL • det • dbt alternative • SQL • data engineering • data pipeline • apache datafusion • apache arrow • parquet • delta lake • duckdb alternative • data orchestration • analytics engineering • medallion architecture • local-first • data warehouse