Caching

Turborepo uses caching to speed up builds, ensuring you never do the same work twice. When your task is cacheable, Turborepo will restore the results of your task from cache using a fingerprint from the first time the task was ran.

12 tasks are being ran in 3 packages, resulting in a ">>> FULL TURBO" cache hit. The total time it takes to restore these tasks from cache is 80 milliseconds.

Turborepo's caching results in significant time savings when working locally - and is even more powerful when Remote Caching is enabled, sharing a cache among your entire team and CI.

On this page, you'll learn:

Good to know:

Turborepo assumes that your tasks are deterministic. If a task is able to produce different outputs given the set of inputs that Turborepo is aware of, caching may not work as expected.

Hit your first Turborepo cache

You can try out Turborepo's caching behavior in three steps:

Create a new Turborepo project

Use npx create-turbo@latest and follow the prompts to create a new Turborepo.

Terminal
npx create-turbo@latest

Run a build for the first time

If you have turbo installed globally, run turbo build in your repository.

Alternatively, you can run the build script in package.json using your package manager.

Terminal
npm run build

This will result in a cache miss, since you've never ran turbo before with this set of inputs in this repository. The inputs are turned into a hash to check for in your local filesystem cache or in the Remote Cache.

Hit the cache

Run turbo build again. You will see a message like this:

A terminal window showing two tasks that have been ran through turbo. They successfully complete in 116 milliseconds.

Because the inputs' fingerprint is already in the cache, there's no reason to rebuild your applications from zero again. You can restore the results of the previous build from cache, saving resources and time.

Remote Caching

Turborepo stores the results of tasks in the .turbo/cache directory on your machine. However, you can make your entire organization even faster by sharing this cache with your teammates and CI.

To learn more about Remote Caching and its benefits, visit the Remote Caching page.

Enabling Remote Cache

First, authenticate with your Remote Cache provider:

Terminal
npx turbo login

Then, link the repository on your machine to Remote Cache:

Terminal
npx turbo link

Now, when you run a task, Turborepo will automatically send the outputs of the task to Remote Cache. If you run the same task on a different machine that is also authenticated to your Remote Cache, it will hit cache the first time it runs the task.

For information on how to connect your CI machines to Remote Cache, visit the Constructing CI guide.

By default, Turborepo uses Vercel Remote Cache with zero configuration. If you'd like to use a different Remote Cache, visit the Remote Caching API documentation

What gets cached?

Task outputs

Turborepo caches the file outputs of a task that are defined in the outputs key of turbo.json. When there's a cache hit, Turborepo will restore the files from the cache.

Providing file outputs

If you do not declare file outputs for a task, Turborepo will not cache them. This might be okay for some tasks (like linters) - but many tasks produce files that you will want to be cached.

If you're running into errors with files not being available when you hit cache, make sure that you have defined the outputs for your task.

Logs

Turborepo always captures the terminal outputs of your tasks, restoring those logs to your terminal from the first time that the task was ran.

You can configure the verbosity of the replayed logs using the --output-logs flag or outputLogs configuration option.

Task inputs

Inputs are hashed by Turborepo, creating a "fingerprint" for the task run. When "fingerprints" match, running the task will hit the cache.

Under the hood, Turborepo creates two hashes: a global hash and a task hash. If either of the hashes change, the task will miss cache.

Global hash inputs

InputExample
Resolved task definition from root turbo.json
and package turbo.json
Changing outputs in either root turbo.json or Package Configuration
Lockfile changes that affect the Workspace rootUpdating dependencies in root package.json will cause all tasks to miss cache
globalDependencies file contentsChanging ./.env when it is listed in globalDependencies will cause all tasks to miss cache
Values of variables listed in globalEnvChanging the value of GITHUB_TOKEN when it is listed in globalEnv
Flag values that affect task runtimeUsing behavior-changing flags like --cache-dir, --framework-inference, or --env-mode
Arbitrary passthrough argumentsturbo build -- --arg=value will miss cache compared to turbo build or turbo build -- --arg=diff

Package hash inputs

InputExample
Package Configuration changesChanging a package's turbo.json
Lockfile changes that affect the packageUpdating dependencies in a package's package.json
Package's package.json changesUpdating the name field in a package's package.json
File changes in source controlWriting new code in src/index.ts

Troubleshooting

Using dry runs

Turborepo has a --dry flag that can be used to see what would happen if you ran a task without actually running it. This can be useful for debugging caching issues when you're not sure which tasks you're running.

For more details, visit the --dry API reference.

Using Run Summaries

Turborepo has a --summarize flag that can be used to get an overview of all of a task's inputs, outputs, and more. Comparing two summaries will show why two task's hashes are different. This can be useful for:

  • Debugging inputs: There are many inputs to a task in Turborepo. If a task is missing cache when you expect it to hit, you can use a Run Summary to check which inputs are different that you weren't expecting.
  • Debugging outputs: If cache hits aren't restoring the files you're expecting, a Run Summary can help you understand what outputs are being restored from cache.

Turning off caching

Sometimes, you may not want to write the output of tasks to the cache. This can be set permanently for a task using "cache": false or for a whole run using the --no-cache flag.

Overwriting a cache

If you want to force turbo to re-execute a task that has been cached, use the --force flag. Note that this disables reading the cache, not writing.

Caching a task is slower than executing the task

It's possible to create scenarios where caching ends up being slower than not caching. These cases are rare, but a few examples include:

  • Tasks that execute extremely fast: If a task executes faster than a network round-trip to the Remote Cache, you should consider not caching the task.
  • Tasks whose output assets are enormous: It's possible to create an artifact that is so big that the time to upload or download it exceeds the time to regenerate it, like a complete Docker Container. In these cases, you should consider not caching the task.
  • Scripts that have their own caching: Some tasks have their own internal caching behavior. In these cases, configuration can quickly become complicated to make Turborepo's cache and the application cache work together.

While these situations are rare, be sure to test the behavior of your projects to determine if disabling caching in specific places provides a performance benefit.

Next steps

Now that you've seen how Turborepo's caching makes your repository faster, let's take a look at how to develop applications and libraries in your Turborepo.

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