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Uppy development

Fork the repository into your own account first. See the GitHub Help article for instructions.

After you have successfully forked the repository, clone it locally.

git clone https://github.com/transloadit/uppy.git
cd uppy

We are using Corepack to manage version of Yarn. Corepack comes pre-installed with Node.js >=16.x, or can be installed through npm. You can run corepack enable to install a yarn executable in your $PATH, or prefix all yarn commands with corepack yarn.

corepack -v || npm i -g corepack
yarn -v || corepack enable
yarn install || corepack yarn install

Our website’s examples section is also our playground, please read the Local Previews section to get up and running.

Requiring files

  • If we are require()ing a file from the same subpackage, we can freely use relative imports as long as the required file is under the src directory (for example to import @uppy/dashboard/src/utils/hi.js from @uppy/dashboard/src/index.js, use require('./utils/hi.js')).
  • But if we want to require() some file from another subpackage - we should use global @uppy requires, and they should always be in the form of @uppy/:packageName/(lib instead of src)/(same path).js


Unit tests

Unit tests are using Jest and can be run with:

yarn run test:unit

End-to-End tests

We use Cypress for our e2e test suite. Be sure to checkout “Writing your first test” and the “Introduction to Cypress”. You should also be aware of the “Best Practices”.

To get started make sure you have your .env set up. Copy the contents of .env.example to a file named .env and add the values relevant for the test(s) you are trying to run.

To start the testing suite run:

yarn e2e

This will run Cypress in watch-mode, and it will pick up and rebuild any changes to JS files. If you need to change other files (like CSS for example), you need to run the respective yarn build:* scripts.

Alternatively the following command is the same as the above, except it doesn’t run build first:

yarn e2e:skip-build

To generate the boilerplate for a new test run:

yarn e2e:generate



To start the Companion server along with Uppy, run:

yarn run dev:with-companion

or if you only want to run Companion

yarn run start:companion

This would get the Companion instance running on http://localhost:3020. It uses nodemon so it will automatically restart when files are changed.

Live example

An example server is running at https://companion.uppy.io, which is deployed with Kubernetes

How the Authentication and Token mechanism works

This section describes how Authentication works between Companion and Providers. While this behaviour is the same for all Providers (Dropbox, Instagram, Google Drive, etc.), we are going to be referring to Dropbox in place of any Provider throughout this section.

The following steps describe the actions that take place when a user Authenticates and Uploads from Dropbox through Companion:

  • The visitor to a website with Uppy clicks Connect to Dropbox.
  • Uppy sends a request to Companion, which in turn sends an OAuth request to Dropbox (Requires that OAuth credentials from Dropbox have been added to Companion).
  • Dropbox asks the visitor to log in, and whether the Website should be allowed to access your files
  • If the visitor agrees, Companion will receive a token from Dropbox, with which we can temporarily download files.
  • Companion encrypts the token with a secret key and sends the encrypted token to Uppy (client)
  • Every time the visitor clicks on a folder in Uppy, it asks Companion for the new list of files, with this question, the token (still encrypted by Companion) is sent along.
  • Companion decrypts the token, requests the list of files from Dropbox and sends it to Uppy.
  • When a file is selected for upload, Companion receives the token again according to this procedure, decrypts it again, and thereby downloads the file from Dropbox.
  • As the bytes arrive, Companion uploads the bytes to the final destination (depending on the configuration: Apache, a Tus server, S3 bucket, etc).
  • Companion reports progress to Uppy, as if it were a local upload.
  • Completed!

Instagram integration

Even though facebook allows using http://localhost in dev mode, Instagram doesn’t seem to support that, and seems to need a publically available domain name with HTTPS. So we will tunnel requests to localhost using ngrok.

Make sure that you are using a development facebook app at https://developers.facebook.com/apps

Go to “Instagram Basic Display” and find Instagram App ID and Instagram App Secret. Put them in a file called .env in the repo root:


Note! ngrok seems to be blocked by Instagram now, so you may have to find an alternative.


ngrok http 3020

Note the ngrok https base URL, for example https://e0c7de09808d.ngrok.io and
append /instagram/redirect to it, such as:


Add this full ngrok URL to Valid OAuth Redirect URIs under Instagram Basic Display.

Edit .env and change to your ngrok URI:

VITE_COMPANION_URL = 'https://e0c7de09808d.ngrok.io'

Go to: Roles -> Roles -> Add Instagram testers -> Add your instagram account

Go to your instagram account at https://www.instagram.com/accounts/manage_access/

Tester invites -> Accept

Now you should be able to test the Instagram integration.


See above Instagram instructions for setting up a tunnel, but replace instagram with zoom in the URL. Note that you also have to add the OAuth redirect URL to OAuth allow list in the Zoom Oauth app settings or it will not work.

Add the following scopes: recording:read, user:read, user_info:read

To test recording a meeting, you need to sign up for a Zoom Pro trial (can be cancelled later), for example using their iOS app.


Before doing a release, check that the examples on the website work:

yarn start
open http://localhost:4000/examples/dashboard

Also check the other examples:

yarn workspace <example-name> start

Releases are managed by GitHub Actions, here’s an overview of the process to release a new Uppy version:

  • Run yarn release on your local machine.
  • Follow the instructions and select what packages to release. Warning: skipping packages results in those changes being “lost”, meaning they won’t be picked up in the changelog automatically next release. Always try to release all.
  • Before committing, check if the generated files look good.
  • When asked to edit the next CHANGELOG, only include changes related to the package(s) you selected for release.
  • Push to the Transloadit repository using the command given by the tool. Do not open a PR yourself, the GitHub Actions will create one and assign you to it.
  • Wait for all the GitHub Actions checks to pass. If one fails, try to figure out why. Do not go ahead without consulting the rest of the team.
  • Review the PR thoroughly, and if everything looks good to you, approve the PR. Do not merge it manually!
  • After the PR is automatically merged, the demos on transloadit.com should also be updated. Check that some things work locally:
    • the demos in the demo section work (try one that uses an import robot, and one that you need to upload to)
    • the demos on the homepage work and can import from Google Drive, Instagram, Dropbox, etc.

If you don’t have access to the transloadit.com source code ping @arturi or @goto-bus-stop and we’ll pick it up. :sparkles:

Website development

We keep the uppy.io website in ./website to keep docs and code in sync as we are still iterating at high velocity.

The site is built with Hexo, and Travis automatically deploys this onto GitHub Pages (it overwrites the gh-pages branch with Hexo’s build at every change to main). The content is written in Markdown and located in ./website/src. Feel free to fork & hack!

Even though bundled in this repo, the website is regarded as a separate project. As such, it has its own package.json and we aim to keep the surface where the two projects interface as small as possible. ./website/update.js is called during website builds to inject the Uppy knowledge into the site.

Local previews

  1. yarn install
  2. yarn start
  3. Go to http://localhost:4000. Your changes in /website and /packages/@uppy will be watched, your browser will refresh as files change.

Then, to work on, for instance, the XHRUpload example, you would edit the following files:

${EDITOR} packages/@uppy/core/src/index.js \
  packages/@uppy/core/src/Plugin.js \
  packages/@uppy/xhr-upload/src/index.js \

And open http://localhost:4000/examples/xhrupload/ in your web browser.

CSS guidelines

The CSS standards followed in this project closely resemble those from Medium’s CSS Guidelines. If something is not mentioned here, follow their guidelines.

Naming conventions

This project uses naming conventions adopted from the SUIT CSS framework.
Read about them here.

To quickly summarize:


Syntax: u-[sm-|md-|lg-]<utilityName>



Syntax: [<namespace>-]<ComponentName>[-descendentName][--modifierName]

.twt-Button /* Namespaced component */
.MyComponent /* Components pascal cased */
.Button--default /* Modified button style */

.Tweet-header /* Descendents */

.Accordion.is-collapsed /* State of component */


This project uses SASS, with some limitations on nesting. One-level-deep nesting is allowed, but nesting may not extend a selector by using the & operator. For example:

/* BAD */
.Button {
  &--disabled {

/* GOOD */
.Button {

.Button--disabled {

Mobile-first responsive approach

Style to the mobile breakpoint with your selectors, then use min-width media queries to add any styles to the tablet or desktop breakpoints.

Selector, rule ordering

  • All selectors are sorted alphabetically and by type.
  • HTML elements go above classes and IDs in a file.
  • Rules are sorted alphabetically.
/* BAD */
.wrapper {
  width: 940px;
  margin: auto;

h1 {
  color: red;

.article {
  width: 100%;
  padding: 32px;

/* GOOD */
h1 {
  color: red;

.article {
  padding: 32px;
  width: 100%;

.wrapper {
  margin: auto;
  width: 940px;

Adding a new integration

Before opening a pull request for the new integration, open an issue to discuss said integration with the Uppy team. After discussing the integration, you can get started on it. First off, you need to construct the basic components for your integration. The following components are the current standard:

  • Dashboard: Inline Dashboard (inline: true)
  • DashboardModal: Dashboard as a modal
  • DragDrop
  • ProgressBar
  • StatusBar

All these components should function as references to the normal component. Depending on how the framework you’re using handles references to the DOM, your approach to creating these may be different. For example, in React, you can assign a property of the component to the reference of a component (see here). This may differ in your framework, but from what we’ve found, the concepts are generally pretty similar.

If you’re familiar with React, Vue or soon Svelte, it might be useful to read through the code of those integrations, as they lay out a pretty good structure. After the basic components have been built, here are a few more important tasks to get done:

  • Add TypeScript support in some capacity (if possible)
  • Write documentation
  • Add an example
  • Configuring the build system

Common issues

Before going into these tasks, here are a few common gotchas that you should be aware of.


Your package.json should resemble something like this:

  "name": "@uppy/framework",
  "dependencies": {
    "@uppy/dashboard": "workspace:^",
    "@uppy/drag-drop": "workspace:^",
    "@uppy/progress-bar": "workspace:^",
    "@uppy/status-bar": "workspace:^",
    "@uppy/utils": "workspace:^",
    "prop-types": "^15.6.1"
  "peerDependencies": {
    "@uppy/core": "workspace:^"
  "publishConfig": {
    "access": "public"

The most important part about this is that @uppy/core is a peer dependency. If your framework complains about @uppy/core not being resolved, you can also add it as a dev dependency

Adding TypeScript Support

This section won’t be too in-depth, because TypeScript depends on your framework. As general advice, prefer using d.ts files and vanilla JavaScript over TypeScript files. This is circumstantial, but it makes handling the build system a lot easier when TypeScript doesn’t have to transpiled. The version of typescript in the monorepo is 4.1.

Writing docs

Generally, documentation for integrations can be broken down into a few pieces that apply to every component, and then documentation for each component. The structure should look something like this:

  • Installation
  • Initializing Uppy (may vary depending on how the framework handles reactivity)
  • Usage
  • For each component
    • Loading CSS
    • Props

It may be easier to copy the documentation of earlier integrations and change the parts that need to be changed rather than writing this from scratch. Preferably, keep the documentation to one page. For the front-matter, write something like:

title: Framework Name
type: docs
module: "@uppy/framework"
order: 0
category: "Other Integrations"

This data is used to generate Uppy’s website. Refer to the section about running the website locally if you’d like to see how the docs look on the website.

Any change of the documentation that involves a security best practice must substantiated with an external reference. See #3565.

Adding an example

You can likely use whatever code generation tool for your framework (ex. create-react-app) to create this example. Make sure you add the same version of @uppy/core to this as your peer dependency required, or you may run into strange issues. Try to include all the components are some of their functionality. The React example is a great… well example of how to do this well.

Integrating the build system

The biggest part of this is understanding Uppy’s build system. The high level description is that babel goes through almost all the packages and transpiles all the Javascript files in the src directory to more compatible JavaScript in the lib folder. If you’re using vanilla JavaScript for your integration (like React and Vue do), then you can use this build system and use the files generated as your entry points.

If you’re using some kind of more abstract file format (like Svelte), then you probably want do to a few things: add the directory name to this IGNORE regex; add all your build dependencies to the root package.json (try to keep this small); add a new build:framework script to the root package.json. This script usually looks something like this:

  "scripts": {
    "build:framework": "cd framework && yarn run build"

Then, add this script to the build:js script. Try running the build:js script and make sure it does not error. It may also be of use to make sure that global dependencies aren’t being used (ex. not having rollup locally and relying on a global install), as these dependencies won’t be present on the machine’s handling building.