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Low-code development

Sumatra's low-code language is Scowl, a proprietary domain-specific language (DSL) for realtime decisioning and AI/ML. It's as approachable as SQL, with the power of Python, and speed of Go. Unlike other languages that separate the analyst from the engineer, the same code is used for data exploration and production to streamline workflows and maintain online/offline consistency.

Why Scowl?

  • Approachable - Designed for anyone who wants to write code, not just specialized engineers
  • Explainable - Easy to interpret data and logic behind every decision
  • Safe & Agile - Validate logic on historical data then deploy straight to production
  • Fast - Built on Go to be blazingly fast


Scowl has a simple, declarative syntax and powerful, stateful features.

emails_per_ip := CountUnique(email by ip last 2 hours)
login_device := Latest<login>(device_hash by acct_id)


Scowl's design was highly influenced by SQRL, created by Josh Yudaken, Pete Hunt, Julian Tempelsman, Paul Mou, Yunjing Xu, and David Newman. We are grateful to TwitterOSS and the project creators for releasing it publicly.

Special thanks to Josh and Pete for making themselves available for conversation to improve this project.