WeCanTrack
Automatically place subids in affiliate links to attribute affiliate conversions to click data
Small application that measures your keyboard/mouse usage.
WhatPulse API is a free Tracking API that requires no API key, is served over HTTPS and has unconfirmed CORS support.
Welcome to the WhatPulse Developer Center! Here you will learn about the APIs we have available; the Web API and Client API. We'll explain the differences below.
Details from developer.whatpulse.org.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Automatically place subids in affiliate links to attribute affiliate conversions to click data
An API to query Brazilian ZIP codes and orders easily, quickly and free
The WhatPulse API is provided by WhatPulse Help Center (developer.whatpulse.org). Welcome to the WhatPulse Developer Center! Here you will learn about the APIs we have available; the Web API and Client API. We'll explain the differences below.
Yes. The WhatPulse API is listed in the Tracking category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The WhatPulse API requires no authentication, so you can start making requests without signing up.
CORS support for the WhatPulse API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The WhatPulse API is served over HTTPS, so it's safe to use in production.