Compare database schemas before migration
Diff two database schema snapshots in your browser so you can spot table, column, type, and index changes before a migration review.
Open the tool, then paste the sample input below. Everything runs locally in your browser.
The problem
Schema changes often arrive as long DDL files or exported definitions. Before approving a migration, reviewers need to see which tables changed, whether columns were dropped, and which differences might require a manual migration step.
Sample input
Before:
CREATE TABLE users (id uuid PRIMARY KEY, email text NOT NULL);
After:
CREATE TABLE users (id uuid PRIMARY KEY, email text NOT NULL, last_login timestamptz);Expected output
Added column: users.last_login timestamptz
No removed tables
No removed columnsHow to do it
- Paste the current schema in the left input.
- Paste the proposed schema in the right input.
- Run the diff.
- Review added, removed, and changed objects.
- Copy the summary into your migration review.
Common mistakes
- Comparing generated SQL that includes environment-specific comments.
- Ignoring removed nullable columns because the migration still applies.
- Reviewing only table names and missing type changes.
- Not checking indexes and constraints after column changes.
Related tools
FAQ
Can I compare production and staging schemas?
Yes. Paste exported schema text from each environment. The comparison runs locally in your browser.
Does this run SQL against my database?
No. It compares pasted schema text and does not connect to any database.
What should I check before approving a migration?
Look for dropped columns, type changes, renamed objects, and missing indexes or constraints.
Is my data uploaded anywhere?
No. This workflow runs locally in your browser unless you explicitly copy or share the result yourself.
This guide uses browser-local tooling. Avoid pasting production secrets unless you understand what the tool displays and shares.
Continue with adjacent browser-based tools for the same workflow.