🚀 Sequelize Schema Diff

Compare Sequelize Schemas Without the CLI

Paste two Sequelize model definitions or generated SQL and get an instant visual diff. See models, attributes, associations, and indexes that changed — then generate the migration SQL. No npx sequelize-cli required.

Diff a Sequelize Schema → 📋 Migration Checklist

How it works

SchemaLens parses your Sequelize schema (model definitions or generated SQL), compares it against another version, and shows you exactly what changed — just like sequelize-cli migration:generate, but in your browser with a visual UI.

📋 Model Diff

See which models were added, removed, or renamed. Catch accidental model deletions before they drop tables.

🔤 Attribute Changes

Spot type changes, allowNull updates, default value changes, and validator modifications at a glance.

🔗 Association Detection

Visualize added or removed belongsTo, hasMany, and belongsToMany associations that affect your data integrity.

📊 Index & Unique

Compare indexes, unique, and composite index declarations. Missing indexes can kill query performance.

📝 Generate SQL

Export migration scripts in PostgreSQL, MySQL, SQLite, SQL Server, or Oracle dialects — ready to run with sequelize-cli db:migrate.

🔗 Shareable Links

Share a diff URL with your team or paste it in a PR review. No screenshots, no copy-paste needed.

SchemaLens vs Sequelize CLI

Both tools compare schemas. SchemaLens adds a visual layer and works without installing anything.

Feature	SchemaLens	sequelize-cli migration:generate	Sequelize UI
Browser-based (no install)	✅ Yes	❌ CLI only	❌ CLI + local DB
Visual diff UI	✅ Yes	❌ SQL files	❌ No diff
Compare two arbitrary schemas	✅ Paste any two	✅ Yes	❌ No
Multi-dialect SQL output	✅ 5 dialects	❌ Target only	❌ No
Shareable diff URLs	✅ Yes	❌ No	❌ No
Breaking change warnings	✅ Yes	❌ No	❌ No
Cross-dialect migrations	✅ Yes	❌ No	❌ No
View/edit live data	❌ No	❌ No	✅ Yes

When to use SchemaLens with Sequelize

SchemaLens complements your Sequelize workflow. Use it when you need speed, shareability, or a visual review layer.

🔍

Code Reviews

Paste the before/after schema into SchemaLens and drop the shareable link in your PR. Reviewers see exactly what changed without running sequelize-cli migration:generate locally.

🏭

Staging vs Production Checks

Export your staging and production schemas, paste them both, and verify the diff before promoting to prod. Catch drift that migrations didn't account for.

👥

Team Collaboration

Not everyone on your team has Sequelize CLI installed or knows migration commands. SchemaLens lets designers, PMs, and junior devs review schema changes in a familiar visual interface.

🔀

Cross-Dialect Migrations

Moving from PostgreSQL to MySQL? SchemaLens shows you the semantic differences and generates the target dialect's migration SQL — something Sequelize CLI can't do across databases.

Works with your Sequelize workflow

SchemaLens is not a replacement for Sequelize migrations. It's a visual companion for the moments when you need to see the diff, share it, or review it quickly.

1️⃣ Export your schema

Copy your model .js / .ts files or run sequelize-cli migration:generate and grab the generated SQL. Paste it into SchemaLens.

2️⃣ Paste the target schema

Paste the older (or newer) version you want to compare against. SchemaLens parses both automatically.

3️⃣ Review the diff

Visual highlights show added models, removed attributes, type changes, and index modifications. Breaking changes are flagged in red.

4️⃣ Generate & share

Export migration SQL in your target dialect, or copy a shareable link to paste in Slack, Jira, or your PR description.