Name: Schemity
Author: Son Tran

Schemity is a cross-platform ERD tool for designing relational database schemas visually and turning that design into real SQL migrations.

Database design usually splits into two disconnected halves. Diagrams live in a drawing tool and drift out of date the moment someone writes a migration, while the migrations that hold the real schema stay invisible and hard to reason about. Schemity keeps one diagram that is both the design and the source of the migration.

Key features:

- Draw the schema by drag an entity header onto another entity to create a foreign key, with 1:N, 1:1 and N:N via an auto-generated junction table. Unique constraints, check constraints and indexes are part of the picture, not afterthoughts buried in migration files.

- Reverse-engineer an existing database into a diagram, evolve it, then generate the exact SQL diff and apply it. PostgreSQL, MySQL, SQL Server and SQLite, over direct or SSH connections, or work in design-only mode with no database at all.

- Import from SQL and DBML. Export to SVG, PNG, DBML, Mermaid, and a data dictionary in HTML, Markdown or Excel.

- Local-first and git-native. Workspaces are folders in your home directory and diagrams are plain JSON, so you commit them next to the code they describe and review them in pull requests.

- Context maps for splitting a large schema into bounded contexts, plus entity templates, multiple tabs, vim-style keyboard navigation and unlimited undo/redo.

Who it is for: backend and full-stack developers, data engineers and architects who own a relational schema and the migrations that change it, particularly teams practicing domain-driven design.

Getting started: a native desktop app for macOS, Windows and Linux (.deb). It is very lightweight that built on Rust and the system WebView, with no Electron and no JVM, and it runs fully offline. Download it from schemity.com, install, then either start a diagram in design-only mode or add a connection to pull in an existing schema. Schemity Lite runs the design side in any modern browser at lite.schemity.com with nothing to install, and diagrams move between Lite and the desktop app as JSON. Free for education, free trial for commercial use.

What makes it different: most tools pick a side. Diagram editors draw pictures but never touch the database, and migration tools change the database but show you nothing. Schemity does both from a single artifact, offline and with no cloud account. It also treats relations and constraints as first-class objects rather than decoration: full routing control with custom waypoints, connection lines that inherit entity colors, and markers that keep multi-column unique constraints visible at a glance.

Latest updates

v2.9.5

Latestv2.9.5 - Aug 18, 20262 weeks ago

v2.9.5 - Aug 18, 2026

✨ Paste a connection string and the dialog fills itself in. PostgreSQL, MySQL and SQL Server URIs are understood, along with a jdbc: prefix and the ADO.NET form the Azure portal hands out. It fails closed rather than guessing: a malformed URL or a bad port is reported instead of being half-applied, and every parameter that was not used is listed rather than dropped in silence.
✨ TLS gains verify-ca and verify-full, so a connection can check the server's certificate against a chain instead of only encrypting the link. Custom root CA and client certificate files are passed through to the drivers, and the two new modes sit alongside the existing ones in the encryption picker. Existing workspace files load unchanged, and SQL Server connections saved as REQUIRE keep verifying rather than quietly dropping to unverified.
✨ Fields now carry an icon that says what they hold: T for text, a hash for whole numbers, digits around a point for fractional ones, a toggle for booleans, a calendar for dates and times, braces for JSON, and a dedicated glyph for UUID. Arrays draw their element's icon inside square brackets, so text[] no longer claims to be a string. Types are grouped by what the value is rather than what an engine calls it, so INT and BIGINT share a glyph, as do DATE and TIMESTAMPTZ. Keys are untouched, because what a field is for outranks what it holds, and anything without an obvious glyph keeps the generic icon rather than borrowing a misleading one.
✨ Documented fields are visible without opening them. A bar on the leading edge of the row marks any field carrying a description, the field-level answer to the corner triangle entities and legends already use. It is scannable down a column, and it is drawn in SVG exports too.
✨ Export a data dictionary in HTML, Markdown or Excel: entities, fields, constraints, relationships and notes, ready to print, share, or commit next to the code.
✨ The context map is a two-way door. An enter icon on the selected box opens that context view, each context view carries a floating "Context Map" button to get back, and the map's exit button lands on Main, which nothing else there could reach. Escape still closes the map in place and returns you to the view you were in, so peeking at the map costs nothing.
🔧 A quick diagram no longer has to answer questions about database transports. Connection setup hides behind a "Connect to a database" link, so the short path is name, database type, naming, save, with no connection vocabulary at all. The link is a single toggle that stays where you clicked it, and "Design only" gives it a visible undo that preserves anything already typed.
🔧 Documenting a column is no longer a schema change. Field descriptions live in the diagram and never reach the database, so a sentence of prose does not produce a migration to review and apply. On MySQL that migration was the worst shape in the system, restating the entire column definition from the diagram to attach a comment. It also fixes silent loss: descriptions used to be overwritten on every refresh, invisibly on PostgreSQL and MySQL and permanently on SQL Server and SQLite. Importing an already documented schema still arrives documented.
🔧 Opening a connection asks for the keychain once instead of more than ten times. Anyone who pressed "Allow" rather than "Always Allow" was prompted again for every command, including ones that went on to answer from cache without using the password.
🔧 The unique marker is legible in both themes and no longer reads as an error. One shared red could not work for a white field and a dark one at once, leaving the glyph meant to catch the eye as the faintest thing on the dark canvas. It is now violet, per theme, which also stops a correct design decision borrowing the vocabulary of a fault.

1 contributed

Duy trì bởiSSon Tran

Reviews & comments

✨ Paste a connection string and the dialog fills itself in. PostgreSQL, MySQL and SQL Server URIs are understood, along with a jdbc: prefix and the ADO.NET form the Azure portal hands out. It fails closed rather than guessing: a malformed URL or a bad port is reported instead of being half-applied, and every parameter that was not used is listed rather than dropped in silence.
✨ TLS gains verify-ca and verify-full, so a connection can check the server's certificate against a chain instead of only encrypting the link. Custom root CA and client certificate files are passed through to the drivers, and the two new modes sit alongside the existing ones in the encryption picker. Existing workspace files load unchanged, and SQL Server connections saved as REQUIRE keep verifying rather than quietly dropping to unverified.
✨ Fields now carry an icon that says what they hold: T for text, a hash for whole numbers, digits around a point for fractional ones, a toggle for booleans, a calendar for dates and times, braces for JSON, and a dedicated glyph for UUID. Arrays draw their element's icon inside square brackets, so text[] no longer claims to be a string. Types are grouped by what the value is rather than what an engine calls it, so INT and BIGINT share a glyph, as do DATE and TIMESTAMPTZ. Keys are untouched, because what a field is for outranks what it holds, and anything without an obvious glyph keeps the generic icon rather than borrowing a misleading one.
✨ Documented fields are visible without opening them. A bar on the leading edge of the row marks any field carrying a description, the field-level answer to the corner triangle entities and legends already use. It is scannable down a column, and it is drawn in SVG exports too.
✨ Export a data dictionary in HTML, Markdown or Excel: entities, fields, constraints, relationships and notes, ready to print, share, or commit next to the code.
✨ The context map is a two-way door. An enter icon on the selected box opens that context view, each context view carries a floating "Context Map" button to get back, and the map's exit button lands on Main, which nothing else there could reach. Escape still closes the map in place and returns you to the view you were in, so peeking at the map costs nothing.
🔧 A quick diagram no longer has to answer questions about database transports. Connection setup hides behind a "Connect to a database" link, so the short path is name, database type, naming, save, with no connection vocabulary at all. The link is a single toggle that stays where you clicked it, and "Design only" gives it a visible undo that preserves anything already typed.
🔧 Documenting a column is no longer a schema change. Field descriptions live in the diagram and never reach the database, so a sentence of prose does not produce a migration to review and apply. On MySQL that migration was the worst shape in the system, restating the entire column definition from the diagram to attach a comment. It also fixes silent loss: descriptions used to be overwritten on every refresh, invisibly on PostgreSQL and MySQL and permanently on SQL Server and SQLite. Importing an already documented schema still arrives documented.
🔧 Opening a connection asks for the keychain once instead of more than ten times. Anyone who pressed "Allow" rather than "Always Allow" was prompted again for every command, including ones that went on to answer from cache without using the password.
🔧 The unique marker is legible in both themes and no longer reads as an error. One shared red could not work for a white field and a dark one at once, leaving the glyph meant to catch the eye as the faintest thing on the dark canvas. It is now violet, per theme, which also stops a correct design decision borrowing the vocabulary of a fault.

No reviews yet

UniMaidUni assistant

14 ngày trước

Schemity giải quyết một bài toán khá quan trọng trong thiết kế cơ sở dữ liệu, đó là giữ cho sơ đồ ER và các migration SQL luôn đồng bộ. Cách tiếp cận kết hợp diagram editor với migration tool từ một artifact duy nhất là khá thông minh, cộng với tính năng reverse-engineer từ cơ sở dữ liệu hiện có. Mô tả sản phẩm rất đầy đủ về kỹ thuật, nhưng bạn có thể xem xét thêm một hoặc hai ví dụ cụ thể về tình huống sử dụng. Chẳng hạn khi refactor một schema lớn hoặc trong một team thực hành domain-driven design, Schemity mang lại lợi ích gì cụ thể. Điều này sẽ giúp các nhà phát triển khác dễ hình dung được khi nào họ cần sản phẩm này. Tiếp tục phát triển tính năng này. Community trên Discord và GitHub của bạn có vẻ khá sôi động, đó là điểm cộng lớn cho sự phát triển dài hạn của sản phẩm.