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Cosmos DB Explorer

UI for Azure Cosmos DB. Powers the Azure Portal,, and the Cosmos DB Emulator

Getting Started

  • npm install
  • npm run build


Watch mode

Run npm start to start the development server and automatically rebuild on changes

Hosted Development (

  • Visit: https://localhost:1234/hostedExplorer.html
  • The default webpack dev server configuration will proxy requests to the production portal backend: This will allow you to use production connection strings on your local machine.

Emulator Development

Setting up a Remote Emulator

The Cosmos emulator currently only runs in Windows environments. You can still develop on a non-Windows machine by setting up an emulator on a windows box and exposing its ports publicly:

  1. Expose these ports publicly: 8081, 8900, 8979, 10250, 10251, 10252, 10253, 10254, 10255, 10256

  2. Download and install the emulator:

  3. Start the emulator from PowerShell:

> cd C:/

> .\CosmosDB.Emulator.exe -AllowNetworkAccess -Key="<EMULATOR MASTER KEY>"

Portal Development


Unit Tests

Unit tests are located adjacent to the code under test and run with Jest:

npm run test

End to End CI Tests

Jest and Puppeteer are used for end to end browser based tests and are contained in test/. To run these tests locally:

  1. Copy .env.example to .env
  2. Update the values in .env including your local data explorer endpoint (ask a teammate/codeowner for help with .env values)
  3. Make sure all packages are installed npm install
  4. Run the server npm run start and wait for it to start
  5. Run npm run test:e2e


We generally adhere to the release strategy documented by the Azure SDK Guidelines. Most releases should happen from the master branch. If master contains commits that cannot be released, you may create a release from a release/ or hotfix/ branch. See linked documentation for more details.



Please read the contribution guidelines.