About Diagram2Code

🎯 Our Mission

Diagram2Code exists to make database schema design faster and less error-prone. Every developer who has hand-written SQL from an ER diagram knows the pain — typos in column names, mismatched foreign keys, forgotten constraints. We eliminate that friction.

We believe the diagram is the source of truth. Your schema, ORM models, and database migrations should all flow from the same visual representation, not drift apart over time. Diagram2Code keeps them in sync.

Our diagram to code approach means you design once in Mermaid or PlantUML and generate correct SQL or ORM code instantly — no hand-editing, no drift. Whether you call it diagram 2 code or diagram-to-code, the goal is the same: let the diagram drive the implementation.

🛠️ What We Built

Diagram2Code is a full-stack tool that accepts Mermaid ER and PlantUML entity-relationship diagrams and generates production-ready output. It ships as a web UI, and a REST API.

⚙️ Technology Stack

Diagram2Code is built with a lean, production-focused stack. The backend is written in Go for performance and low resource consumption; the frontend is built with Svelte for a reactive, component-based UI.

💡 Why We Built This

The idea for Diagram2Code came from a frustrating afternoon spent hand-writing SQL migrations. We had a perfectly good ER diagram in Mermaid, showing every table, column, and relationship — and yet we were still copying column names by hand, getting types wrong, and forgetting NOT NULL constraints. The diagram was the source of truth, but the code was not following it.

We searched for a tool that could close this gap. We found diagram editors, and we found schema editors, but nothing that treated the diagram as the canonical description of the database. So we built it ourselves.

The first version of Diagram2Code was a Go script that ran in a CI pipeline and generated a schema.sql from a Mermaid file. It saved hours every week. When we showed it to other developers, they wanted it too — so we turned it into a web tool and opened it up.

👥 Who Uses Diagram2Code

Diagram2Code is used by a wide range of developers and teams. Here are the most common use cases we hear about:

Backend developers use it to kick-start new projects. Instead of writing boilerplate SQL from scratch, they sketch the data model in Mermaid, generate a migration, and focus on the business logic that actually differentiates their product.

Database architects and data engineers use it to turn design artifacts into deployable schema code. The diagram stays in the repository as living documentation — not just a picture, but the source that generates the real schema.

Full-stack teams use the ORM generation features to keep their Go, Python, TypeScript, or Java model code in sync with the database schema. When the diagram changes, the models regenerate — no drift, no stale types.

Students and bootcamp graduates use it to learn SQL DDL syntax by reverse-engineering the output. Seeing how a diagram maps to concrete SQL statements with primary keys, foreign keys, and constraints makes the concepts tangible.

Technical writers and architects use the live Mermaid preview to produce clean, shareable database diagrams embedded directly in Markdown documentation and README files.

📐 Diagram-Driven Development

Diagram-Driven Development (DDD) is the practice of treating diagrams as executable specifications rather than passive documentation. Instead of maintaining diagrams and code separately — and watching them drift apart over time — you declare the diagram as the source of truth and generate all downstream artifacts from it automatically.

This is not a new idea. Database administrators have worked diagram-first for decades. What is new is the tooling that makes it practical for everyday developers working in modern stacks with Go, Python, TypeScript, or Java ORMs and cloud-hosted databases.

Diagram2Code is our contribution to this philosophy. When you commit a .mmd or .puml file to your repository and run the converter in CI, your SQL migrations and ORM model files are always derived from the same diagram. They cannot drift. They cannot disagree. And when you add a column or a table, you update one file — the diagram — and regenerate everything else.

We think this is the right way to manage database schemas, and we are building the tools to make it the default.

🗺️ Where We're Going

We're actively working on code generation from class diagrams — generate full project scaffolds (REST controllers, services, repositories) from a UML class diagram. We're also exploring bulk conversion, ZIP downloads, and deeper IDE integrations.

Want to follow along or contribute? Check out our documentation, star us on GitHub, or get in touch.