See it in action
Paste two schemas. Click Compare. Get the diff and migration SQL in seconds.
SchemaLens is a privacy-first schema diff tool for PostgreSQL, MySQL, SQLite, SQL Server, and Oracle. Paste two CREATE TABLE dumps, get a visual semantic diff, and generate ready-to-run ALTER TABLE scripts.
100% client-side. Your schemas never leave your browser.
Paste two schemas. Click Compare. Get the diff and migration SQL in seconds.
100% client-side. Your schema never hits a server. Verify it yourself in DevTools → Network.
Open the URL and diff in 10 seconds. No install, no signup, no backend.
Understands tables, columns, types, defaults, constraints, indexes, triggers, views — not just text.
Risk score (0–100) flags dangerous migrations before they hit production.
Share diffs via base64-encoded URLs. Paste into Slack, email, or PR descriptions.
Run npx schemalens-cli locally or in GitHub Actions, GitLab CI, and Bitbucket Pipelines.
Real feedback from developers who discovered SchemaLens.
"I was manually diffing schema dumps with diff -u like a caveman. SchemaLens turned a 20-minute chore into a 10-second paste-and-click. The migration SQL alone saved me an hour last week."
"The breaking change detection caught a dropped column that would have broken our staging environment. I pasted two schemas, hit compare, and immediately saw the red warning. Game changer."
"Zero setup, zero backend, instant results. I used it in a PR review to verify a teammate's migration was safe. Exported the markdown diff straight into the PR description. Perfect."
147 days. 42 blog posts. 50+ micro-tools. One developer. One mission.
Thanks to everyone who upvoted, commented, and shared feedback. You made this possible.
Hey Product Hunt 👋
I built SchemaLens because I was tired of squinting at text diffs between schema dumps and manually writing ALTER TABLE statements. Every deploy felt like a gamble — did I miss a dropped column? Did a foreign key change break something?
SchemaLens is my answer: paste two CREATE TABLE dumps, get a semantic visual diff, and generate ready-to-run migration SQL. Zero backend. Zero signup. Your schemas never leave your browser.
The past 147 days have been a wild ride — 42 blog posts, 50+ micro-tools, 51+ SEO landing pages, a CLI, a VS Code extension, and a Chrome extension. All built in public. If you have feedback, a feature request, or just want to say hi, drop a comment below or email me directly.
Thank you for checking it out. — Jochen
No signup required. No data leaves your browser.
