I am working on Google API like chat, contacts and so on...
I am stuck on developer_key
as mentioned in gdata doc.
You can get this at https://code.goog
Go to https://code.google.com/p/google-api-php-client/wiki/OAuth2
Scroll down to where it says 'Visit the Google API Console to generate your developer key, OAuth2 client id, OAuth2 client secret, and register your OAuth2 redirect uri. Copy their values since your will need to input them in your application.'
Click on the 'Google API Console' link.
When it pops up and says 'Welcome to the new Google Developers Console! Prefer the old console? Go back | Dismiss' Click on 'GO BACK'
Recent Update July 2017:
You can get a Developer_Key from here Get your Google Developer Key
Check this tutorial
{select as answered, if it answered.}
if you check this code reference, it states
Set DEVELOPER_KEY to the "API key" value from the "Access" tab of the Google APIs Console http://code.google.com/apis/console#access`
Wiki on step by step to get API Key & secret
http://code.garyjones.co.uk/google-developer-api-key
OR
If say, for instance, you have a web app which would require a API key then check this:
The Service application that you have created can be used by your Web apps such as PHP, Python, ..., etc.
I explored the google docs and found that developer key and api is same thing.
API Key is your developer key. Hit https://www.googleapis.com/webfonts/v1/webfonts?key= in your browser by enabling web fonts api and you will see result.
Refer this blog http://code.garyjones.co.uk/google-developer-api-key/ for more information
First activate Google+ API, then you will get "Simple API access" box, from there you can get developer key as API key https://code.google.com/apis/console/?api=plus or read this: http://code.google.com/p/google-api-php-client/wiki/OAuth2