Help Spread the Word 🚀

🐦 Twitter / X

Just discovered SchemaLens — a free browser-based SQL schema diff tool that generates migration scripts instantly.

No install. No signup. No data leaves your machine.

Perfect for reviewing migrations before deploying to prod.

→ https://schemalens.tech

#buildinpublic #postgresql #mysql #sql

💼 LinkedIn

If you work with databases, this free tool will save you hours.

SchemaLens compares two SQL schemas in your browser and generates the migration scripts to get from one to the other. No CLI setup, no cloud upload, no account required.

I just paste two CREATE TABLE dumps and get a visual diff + ready-to-run ALTER TABLE statements in seconds.

They just launched on Product Hunt with a lifetime deal ($39 once) and a founding member giveaway for the first 50 developers.

Worth bookmarking for your next migration review.

→ https://schemalens.tech

#database #postgresql #mysql #sql #devtools #producthunt

📧 Email to a teammate

Hey — found a tool you might like: SchemaLens (https://schemalens.tech)

It diffs two SQL schemas in the browser and generates ALTER TABLE migration scripts. I just used it to review a staging-to-prod schema drift and it caught a column type change I would have missed.

Free tier covers most use cases. They have a lifetime Pro deal for $39 if you need unlimited tables and exports.

Worth keeping in your toolkit.

🗣️ Reddit — r/PostgreSQL

I built a browser-based schema diff tool for PostgreSQL (and MySQL/SQLite). No signup, no upload, no backend.

I got tired of comparing schema dumps by hand when reviewing migration PRs. Text diffs of SQL dumps are noisy and miss semantic meaning—like whether a column was renamed vs dropped and re-added.

SchemaLens parses CREATE TABLE statements, shows you exactly what changed (tables, columns, types, defaults, constraints), and generates the correct ALTER TABLE script for your dialect.

Privacy-first: everything parses in your browser. Your schema never touches a server.

Live demo: https://schemalens.tech

Free for schemas up to 15 tables. Would love feedback from real PostgreSQL users—especially on edge cases like composite PKs, enums, arrays, or exotic types.

🗣️ Reddit — r/MySQL

Compare MySQL schemas in your browser and generate ALTER TABLE scripts instantly

I built a tool that compares two MySQL schemas and generates the correct migration SQL—no install, no signup, no data upload.

SchemaLens parses your CREATE TABLE dumps, detects added/removed/modified columns, type changes, nullability flips, and default value changes, then outputs MySQL-specific ALTER TABLE syntax (MODIFY COLUMN, ADD COLUMN, DROP COLUMN, etc.).

Key features for MySQL users:
- Handles AUTO_INCREMENT, backtick identifiers, and COLLATE
- Detects when a column change requires MODIFY COLUMN vs simpler ALTER
- Shows visual diff before you run anything
- 100% client-side — paste your schema, it never leaves your browser

Try it: https://schemalens.tech

Free for schemas up to 15 tables. If you hit edge cases with MySQL-specific syntax (generated columns, spatial types, etc.), I'd love to know.

🗣️ Reddit — r/webdev

Showoff Saturday: I built a zero-backend schema diff tool that runs entirely in the browser

For my side project this month I built SchemaLens—a SQL schema diff tool with zero backend. No server, no database, no API. Just vanilla JS parsing CREATE TABLE statements and generating migration scripts.

Tech stack:
- Vanilla HTML/CSS/JS (no frameworks)
- Custom SQL tokenizer + parser (~600 lines)
- Semantic diff engine
- Dialect-aware migration generator (PostgreSQL, MySQL, SQLite, SQL Server, Oracle)

What it does:
- Paste two schema dumps
- See tables added/removed/modified with color coding
- Get per-column change details (type, nullability, default, PK, unique)
- Download migration SQL or export as Markdown for PRs

Why no backend?
Your schema structure reveals a lot about your data model. I wanted a tool where privacy is the default, not a feature.

Live: https://schemalens.tech

Free tier covers 15 tables. Lifetime Pro is $39 one-time for unlimited access.

Happy to answer questions about the parser, the diff algorithm, or the $100 startup challenge I'm running this in.

🗣️ Reddit — r/SQL

SchemaLens (https://schemalens.tech) is a free browser-based schema diff tool I have been using. Paste two CREATE TABLE dumps, get a visual semantic diff + generated migration scripts.

Supports PostgreSQL, MySQL, SQLite, SQL Server, and Oracle. Runs entirely client-side so your schema never leaves the browser. Also has a CLI (`npx schemalens-cli`) if you prefer terminal workflows.

They just launched on Product Hunt with a $39 lifetime deal and a founding member giveaway.

💬 Hacker News — Follow-up Comment

Thanks for the interest! A few answers to common questions:

Why not use existing tools like migra/apgdiff/Liquibase?
They're great, but they require installation, a database connection, or Python. SchemaLens is for the "I need to check this right now" moment—paste, compare, done. If you need managed migration lifecycles, Liquibase is the better fit. SchemaLens complements it for quick ad-hoc diffs.

What about more complex objects?
We parse CREATE TABLE, CREATE INDEX, views, functions, and triggers. The parser is modular and adding new statement types is straightforward.

Privacy / self-hosting?
Everything runs client-side. Clone the repo, open app.html in a browser. The "backend" is air. Verify in DevTools → Network.

Pricing?
Free for up to 15 tables. Lifetime Pro is $39 once. No subscription, no recurring charges.

Live: https://schemalens.tech

🚀 IndieHackers

Launched SchemaLens — a privacy-first SQL schema diff tool. Built in public.

I just launched SchemaLens, a browser-based SQL schema diff tool for PostgreSQL, MySQL, and SQLite.

The problem: Reviewing database migrations by comparing two SQL dumps is tedious and error-prone. Text diffs miss semantic meaning. CLI tools require installation and database connections.

The solution: Paste two CREATE TABLE dumps into SchemaLens. Get an instant visual diff and a dialect-correct migration script. No install, no signup, no backend.

Why privacy-first matters: Your schema structure reveals a lot about your business logic. SchemaLens parses everything in the browser. Your data never touches a server.

Stack: Vanilla HTML/CSS/JS. Custom SQL parser. Vercel hosting. $0 infrastructure cost.

Monetization: Free for 15 tables. Lifetime Pro at $39 one-time for unlimited access.

Live: https://schemalens.tech

I'm building this as part of a 12-week $100 startup race (documenting everything publicly). 147 days, 50+ micro-tools, 51+ SEO pages. Would love feedback from developers and indie hackers alike.

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