SQL/KQL Linter tool

If you’ve ever pushed a query and then realized it was doing far more work than expected, this tool is for you.

We just launched a new SQL & KQL Linter designed to catch common mistakes early — before they become incidents, slow dashboards, or expensive scans. It supports T-SQL, Standard SQL, PL/SQL, MySQL, PostgreSQL, and KQL (Kusto), and everything runs entirely in your browser.

That last point matters: your query text never leaves your machine.

What it checks The linter currently includes 27 rules across SQL and KQL, including:

DELETE / UPDATE without WHERE SELECT * anti-patterns implicit joins and missing aliases non-SARGable predicates (functions wrapped around indexed columns) unused CTEs KQL-specific checks like missing time filters, late filtering, search overuse, and unused let variables Results are grouped by severity (Error, Warning, Info) so you can focus on the highest-risk items first.

Why we built it Most teams have formatting tools, but formatting alone doesn’t prevent dangerous logic. This linter adds a second layer: fast, actionable feedback about correctness, maintainability, and performance hygiene.

It’s not meant to replace query tuning or query plans — it’s meant to catch the obvious and the costly, quickly.

Try it Paste a query, choose your dialect, click Lint Query, and review the findings. Use it during development, PR review, or when triaging production queries you didn’t write.

Small guardrails, fewer surprises.