Ttext2mermaid

AI ERD generator from description

Describe entities and relationships. Get a Mermaid ERD with keys and cardinality.

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Try one of these — click to open in the generator

Blog schema: users, posts, comments
Blog database schema: users (id, email, name, created_at), posts (id, user_id FK, title, body, published_at), comments (id, post_id FK, user_id FK, body, created_at). A user can write many posts. A post has many comments. A user can leave many comments.
SaaS multi-tenant schema
Multi-tenant SaaS: organizations (id, name, plan), users (id, org_id FK, email, role), workspaces (id, org_id FK, name), documents (id, workspace_id FK, author_id FK, title, content). Each organization has many users and workspaces. Each workspace has many documents. Users author many documents.
E-commerce: products, orders, line items
E-commerce schema: customers (id, email), products (id, sku, name, price), orders (id, customer_id FK, total, status, placed_at), order_items (id, order_id FK, product_id FK, quantity, unit_price). Customer places many orders. Each order has many line items. Each item references one product.
Analytics event schema
Product analytics schema: users (id, anonymous_id, identified_at), events (id, user_id FK, name, timestamp, properties json), sessions (id, user_id FK, started_at, ended_at, device), page_views (id, session_id FK, url, referrer, duration_ms).

When to use this

Entity relationship diagrams (ERDs) are how you communicate a database schema without dumping raw DDL on the reader. They show entities as tables, their columns with types, primary and foreign keys, and — critically — the cardinality of relationships (one-to-one, one-to-many, many-to-many). Reach for an ERD when you're designing a new schema before writing migrations, when you're onboarding an engineer to an existing codebase, or when you're writing an architecture doc that needs to justify why the data model looks the way it does. They're also invaluable when planning a migration or refactor — you can annotate which tables are being consolidated or split. Mermaid's erDiagram syntax uses crow's foot notation and supports column types, PK/FK markers, and relationship labels, which makes it detailed enough for real design docs. Where it falls short: it doesn't show indexes, constraints beyond keys, or physical storage details. For those, a full modeling tool like dbdiagram.io or an ORM's schema visualization tool goes deeper — but for the 90% of "let's talk about the shape of this data" conversations, an ERD in plain text you can commit alongside your migration files is exactly right.

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