60+ free tools · 5 SQL dialects · Zero setup

Everything you need to diff schemas, generate migrations, and ship safely

SchemaLens is the complete toolkit for comparing SQL schemas, catching breaking changes, and generating ready-to-run migration scripts — right in your browser, CLI, or CI pipeline.

Try It Free → See Live Demo

No signup required. Free tier includes 15 tables.

See the diff in seconds

Paste two schema dumps. Get a visual diff, breaking-change warnings, and a migration script instantly.

users.sql — Added Table

Before

-- No users table yet

After

CREATE TABLE users ( id SERIAL PRIMARY KEY, email VARCHAR(255) NOT NULL UNIQUE, created_at TIMESTAMP DEFAULT now() );
Add Table users (3 columns)
📊 1 table added ⚡ 0 breaking changes 🟢 Low Risk
Run This Diff Yourself →

Built for real-world schema workflows

From side projects to enterprise teams, SchemaLens handles the edge cases so you don't have to.

🔍

Visual Schema Diff

Side-by-side comparison of tables, columns, indexes, constraints, views, triggers, and functions. See exactly what changed at a glance.

5 dialects
⚡

Migration Script Generation

Generate ready-to-run ALTER TABLE scripts for PostgreSQL, MySQL, SQLite, SQL Server, and Oracle. Copy and execute in seconds.

Pro feature
🛡️

Breaking Change Detection

Automatically flags dangerous changes — dropped columns, type narrowing, NOT NULL additions, dropped tables — before they hit production.

14 warning types
📊

Risk Scoring

Every diff gets a 0-100 risk score based on the number and severity of changes. Know at a glance if a migration needs extra review.

Real-time
↩️

Rollback Generation

Generate reverse migration scripts to undo any change. Safely experiment with schema changes knowing you can revert instantly.

Pro feature
📋

PR Summaries & Reports

Copy a markdown summary for PR descriptions, generate a branded PDF report for Jira/Linear, or send results to Slack in one click.

Pro feature

Works where you work

SchemaLens fits into every step of your development workflow — from local editing to production CI.

GitHub Action

Auto-diff schema files on every pull request with risk scores and breaking-change comments.

Setup Guide →

VS Code

Diff schemas without leaving your editor. Right-click any two SQL files and compare instantly.

Install →

Chrome Extension

Diff SQL you find on any webpage. One-click "Diff in SchemaLens" button on GitHub PRs.

Get Extension →

CLI

Run schema diffs from your terminal. Perfect for CI pipelines and automation scripts.

Docs →

REST API

Programmatic access to the diff engine. Free tier available for open-source projects.

API Docs →

Built for every role

Whether you're a solo developer or running platform engineering for a team, SchemaLens has you covered.

Ship schema changes with confidence

Stop eyeballing schema dumps. Paste your old and new schema, see the diff instantly, and get a migration script you can run immediately.

  • Free for schemas up to 15 tables
  • No account or signup required
  • Works in your browser — no install needed
  • Copy-ready migration scripts
  • Breaking change warnings before you deploy
Open Web App →
AddColumn users.avatar_url VARCHAR(512)
ModColumn posts.status VARCHAR(20) → VARCHAR(50)
DelColumn orders.legacy_id (breaking)
🟡 Medium Risk — 1 breaking change

Review schema changes as a team

Catch breaking changes during code review, not during deploy. Every PR gets an automatic schema diff with risk scoring and migration warnings.

  • Shareable diff links for Slack/Discord
  • GitHub Action for automatic PR comments
  • Team workspace with shared history
  • PDF reports for audit trails
  • Admin dashboard with usage analytics
Book a Team Demo →
🤖 SchemaLens Bot commented 2 minutes ago
Schema Diff Report · Risk Score: 42/100

⚠️ Breaking: users.phone dropped
✅ 2 tables added · 1 modified · 0 removed
ALTER TABLE users DROP COLUMN phone;

Automate schema validation in CI

Add the SchemaLens GitHub Action to your repo and catch schema drift before it reaches production. Works with any migration framework.

  • Zero-config GitHub Action setup
  • Fails builds on high-risk schema changes
  • Supports Prisma, Drizzle, TypeORM, Sequelize, raw SQL
  • Free diff API for open-source projects
  • Self-hosted CLI for private pipelines
View Action Setup →
# .github/workflows/schema.yml
- name: Schema Diff
  uses: aimadetools/race-kimi@v1
  with:
    schema-old: base.sql
    schema-new: head.sql
    dialect: postgres
    fail-on-breaking: true

SchemaLens vs. doing it manually

See how SchemaLens compares to the workflows developers use today.

Manual diff pg_dump / mysqldiff SchemaLens
Visual side-by-side diff ✗ ✗ ✓
Breaking change detection ✗ ✗ ✓ Auto-detect 14 types
Migration script generation ✗ ✗ ✓ All 5 dialects
Risk scoring ✗ ✗ ✓ 0-100 score
Rollback scripts ✗ ✗ ✓ One-click
PR comment generation ✗ ✗ ✓ Markdown copy
CI / GitHub Action ✗ ✗ ✓ Native
Browser-based (no install) ✗ ✗ ✓
Cost Hours of engineering time Free + maintenance $39 one-time
5
SQL Dialects
60+
Free Micro-Tools
200+
SEO Pages
$39
Lifetime Pro

Frequently asked questions

What is included in the free tier? ▼
The free tier includes visual schema diff, breaking change detection, and risk scoring for schemas up to 15 tables. No signup required. Pro unlocks unlimited tables, migration script generation, rollback scripts, PDF reports, PR summaries, and all CI integrations.
Which databases are supported? ▼
SchemaLens supports PostgreSQL (including Supabase, Neon, TimescaleDB), MySQL (including MariaDB, PlanetScale), SQLite, SQL Server (including Azure SQL), and Oracle.
Do I need to install anything? ▼
Nope. The web app works entirely in your browser — your schema data never leaves your machine. Optional integrations include the VS Code extension, Chrome extension, CLI, and GitHub Action.
Is my schema data private? ▼
Yes. The core diff engine runs entirely client-side in your browser. We never see your schema unless you explicitly choose to save it to your account (optional).
What does "Lifetime Pro" mean? ▼
One payment of $39 gets you unlimited access to all Pro features forever — no subscriptions, no renewal fees. Includes all future updates and new integrations.
Can I use SchemaLens in my CI/CD pipeline? ▼
Yes. The SchemaLens GitHub Action automatically diffs schema files on every pull request. We also offer a free REST API and a CLI for custom pipelines.

Stop diffing schemas by hand

Join thousands of developers who use SchemaLens to catch breaking changes, generate migrations, and ship schema updates with confidence.

Try It Free → View Pricing

Free for schemas up to 15 tables. Lifetime Pro $39 — one-time payment.