What is SLayer?

SLayer is an embeddable semantic layer designed for AI agents and humans to query data warehouses using governed, structured requests instead of raw SQL. It handles database connectivity, SQL translation, query-time aggregations and transforms (like time shifts, ratios, period changes), row-level security, and multi-stage queries. Agents and apps interact via MCP (stdio or SSE), REST API, Python SDK, CLI, Flight SQL, or a Postgres wire facade. Models can be defined as YAML code, auto-generated from database introspection, or imported from dbt/Cube/OSI, and can be edited at runtime without rebuilds. A memory store with semantic search captures business context. SLayer is MIT licensed and runs on Python 3.10+.

Should you self-host SLayer?

SLayer scores 50/100 on selfhost.directory (how scoring works) and ranks #50 of 125 in AI. It has 314 GitHub stars.

It shipped 10 stable releases in the past year. The latest, v1.4.1, came out on 22 October 2026. New versions land roughly every 4 days.

Setup is moderate: expect some configuration beyond a single command. It is MIT-licensed and written mostly in Python.

Its closest alternative on selfhost.directory is ComfyUI (93/100, 143 668 stars). It scores higher overall, so compare the two before you pick. See SLayer vs ComfyUI side by side.