Advise needed on outsourcing the recording of unique views

Question

I have an online image sharing platform based on PHP5 + CodeIgniter. I would like the application to show to the user the number of unique views per image. Users can access image pages anonymous or signed in.

Although I know how to implement such a thing myself, I prefer to "outsource" the recording of unique pageviews, for reasons of performance and complexity (determining unique pageviews). My requirements for such a service:

• Must record unique page views
• Must have an API that allows me to get the #pageviews for one specific page programmatically. This goes beyond just displaying it, I may need to do calculations with this number
• Semi-realtime information is good enough. Reasonable delays are acceptable
• Low cost or free

My question is: Do you know of such a service and which one would you recommend or have experience with? In your answer, please assume an "outsourced" scenario, not DIY.

Answer 1

Piwik is a self-hosted, Open Source tool that sports an API. I have no experience with it yet, but looking at the API docs, it might be able to do what you need (no guarantees though).