Convex is a backend development platform for building web and mobile applications with a single structure for data storage, server functions, and client interaction. It removes the traditional separation between database code and server code by running both within one TypeScript-based system. Developers define data operations and backend behavior in one place. Instead of managing separate database queries, API endpoints, and synchronization layers, Convex provides one interface for storing and accessing data. This reduces repeated logic across different parts of an application.

The platform keeps application state consistent across devices without manual synchronization logic. When data changes on the server, updates are sent automatically to connected clients. This removes the need for polling systems or custom WebSocket setups. Convex also supports query definitions that run directly on stored data. These queries execute on the backend and return results in a controlled format, which reduces the need to build separate API endpoints for each data request.

Data Storage with Reactive Query Execution

Convex includes a built-in database that uses document-style storage with indexed access. Data is stored in collections such as users, messages, orders, or events. Queries in Convex are reactive, so when data changes, all dependent queries run again automatically. Clients subscribed to those queries receive updated results without extra request logic. This removes the need for manual cache updates or synchronization between client and server data.

The system keeps stored data and application views aligned by recalculating query results whenever changes occur. The database also supports validation rules for stored records. Developers can define expected data shapes, which reduces inconsistencies in stored information. Indexing helps speed up data retrieval for frequently used fields, which supports applications that need fast access to records, such as messaging tools or live dashboards.

Server-Side Functions Written in TypeScript

Convex uses TypeScript to define server functions that handle application logic. These functions run on the backend and interact directly with stored data. Each function can read and write data while following consistent execution rules. This removes the need for separate API routing. Developers define functions for actions such as creating records, updating data, or fetching filtered results. Type safety is built into this layer, so function inputs and outputs use TypeScript types, which helps catch data mismatches early in development.

Server functions run in a managed environment, so there is no need to set up or maintain servers manually. This reduces deployment work and speeds up iteration. Convex also supports scheduled functions that run at set intervals for tasks such as cleanup jobs, reporting, or background processing without external cron tools. All functions interact with the same data layer, which keeps logic and data handling consistent across the system.

Application Patterns Across Interactive Products

Convex is used for applications that require frequent updates and shared data views, including collaborative tools, messaging systems, dashboards, and content platforms. In collaboration tools, multiple users can edit the same data and see changes in real time, with updates from one user appearing immediately for others without a page refresh. Messaging systems benefit from reactive queries, where new messages appear instantly for all users in a conversation. Message history is stored and retrieved in a structured format.

Dashboards use Convex to display live data from backend sources, with metrics and logs updating automatically without repeated requests. Convex also supports authentication built into application logic. User identity can be passed into server functions to control access to data based on defined rules. For web and mobile applications, Convex reduces the need for multiple backend services, since data storage, server execution, and live updates run in one system. This simplifies early development work because database setup, API design, and synchronization logic are handled together. Developers can focus on application behavior instead of infrastructure setup. Convex also supports scaling as usage grows, with the system managing data and function execution without requiring major changes to backend architecture. The same rules apply across small and large applications, which keeps development patterns consistent across different project sizes. Across these use cases, Convex provides a single system for data handling and server logic within one execution layer.

Jamie Turner, Co-Founder & CEO, Convex