Language
TypeScriptlinear.app
The single language across the stack, from database models to GraphQL resolvers and UI components.
UI library
Reactlinear.app
Builds the web and desktop interface.
Hosting
Google Cloudlinear.app
Main cloud provider, starting in us-east1.
Kuberneteslinear.app
Orchestrates the services running on Google Cloud.
Terraformlinear.app
Describes the infrastructure as code, with the region passed in as a variable.
Why: Moving to infrastructure as code made spinning up a second region a lot easier.
Cloudflare Workerslinear.app
Proxy that authenticates each request and routes it to the user's region.
Why: Linear already used Cloudflare Workers extensively, so it was an easy decision.
Database
PostgreSQLlinear.app
Main database, kept as a single instance per region.
Styling and UI kit
styled-componentslinear.app
Styles the React components.
Data fetching
MobXlinear.app
Manages reactive state on the front end on top of the synced data.
Linear sync engine (WebSockets)linear.app
In-house sync framework over WebSockets that keeps data on the client and syncs changes in real time.
Why: Built for speed and offline support, which Linear treats as core product values.
GraphQLlinear.app
Powers the public API and SDK, and also the internal API between services.
Why: For service-to-service calls they picked it because the codebase already had strong GraphQL tooling.
Redislinear.app
Cache in the back end, including the cursors of the sync engine.
Google Cloud Pub/Sublinear.app
Fans background tasks out to every region.
Why: It kept the authentication service simple, answering only HTTP requests.
Backend framework
Node.jslinear.app
Runs the back-end services.
Temporallinear.app
Runs durable workflows, including the agentic workload system at production scale.
From day one, Linear set speed as a core product value: data stored locally, no page reloads, and the app working offline, plus real-time sync and teammate presence for multiplayer.
To get there, the team built a proprietary sync framework over WebSockets designed for speed and offline support. CTO Tuomas Artman has given talks on how the engine works and how it had to change as Linear grew.
Sources:linear.app linear.app linear.app
Linear's engineers work in TypeScript everywhere, from database models to GraphQL resolvers and UI components. The front end is React with MobX and styled-components; the back end is Node with Postgres, Redis and Temporal.
The same GraphQL layer powers the public API and SDK, so customers integrate with the API the team uses itself.
Sources:linear.app
In 2024 Linear added a European region. Its infrastructure had been managed by hand in Google Cloud's us-east1, so the first step was moving it to Terraform, which made spinning up a second region much easier.
Instead of sharding Postgres, they replicated the entire deployment per region, so developers still write code against a single database instance. A small authentication service, a Cloudflare Worker that routes each request to the right region, and Google Cloud Pub/Sub for background tasks across regions tie it together.
Sources:linear.app
In January 2024 a database migration deleted data and Linear restored the database from a backup taken hours earlier. The post-mortem describes a database cache in front of Postgres and sync cursors cached in Redis, both of which made recovery harder.
The team responded with CI warnings for dangerous migrations, tighter access to production databases and dry runs in staging.
Sources:linear.app
Found on the homepage with the open Wappalyzer rules (HTML, scripts and headers). It shows what runs in the browser, not the whole backend.
Checked on 2026-10-29. Every tool links to the public source that shows it.
