1
Clone the cal.com repository
Please clone the cal.com repository. You can do it by following the instructions provided in Installation
2
Add license key in .env
Add a staging license key that goes in as value for 
CALCOM_LICENSE_KEY in your root .env file.You can use the following as staging license key3
Start development server and create API key
Start the cal.com server using 
yarn dev on localhost and create the test API keys by visiting /settings/developer/api-keys4
Copy .env.example file
Copy the 
.env.example file to .env file by running cp apps/api/v1/.env.example apps/api/v1/.envfrom root folder5
Start API server and test API
Start the API server by running 
yarn workspace @calcom/api dev and start testing your API locallyBy default, the app server runs on port 3000 and the API server runs on port 3003