In web development, a mashup is a web page or application that uses and combines data, presentation or functionality from two or more sources to create new services.

There are many sources for getting data (raw information). Governments are good examples.
However many of those cost and have complicated licensing. For instance SMHI in Sweden sells temperature data meanwhile our neighbor country Norway gives it away for free.

One would say what kind of application are you building and what data do you need? I would say give me some interesting data and I will do a good mashup of it. I could just plot it on Google maps for instance.

So the question is: Where can I get free data?

Note: I'm not interested in data mining using a webcrawler!

Please share your sources with me.

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  • What kind of data are you looking for? Just any data you can get for free? – Jetti Nov 16 '10 at 18:50
  • Anything data that could have a meaning to a large amount of people. – Amir Rezaei Nov 16 '10 at 19:03
  • 1
    How about odata.stackexchange.com? – ChrisF Nov 16 '10 at 19:07
  • @ChrisF: "This page contains the following errors: error on line 2 at column 29: Char 0x0 out of allowed range Below is a rendering of the page up to the first error." When clicking on the odata link. – Chris Nov 16 '10 at 19:38
  • @Chris - It works OK for me, but if you've got a repeatable case report the problem to the team on MSO. I'm just a moderator ;) – ChrisF Nov 16 '10 at 19:43

12 Answers 12


For general information, a good place to start might be Wikipedia's Open Data page - specifically the bottom parts of the page (Organisations promoting open data, See also, and External Links)

I was going to turn the rest of this post into a list of data sources for country and regional based data ... but the Guardian UK Newspaper has already gone and compiled a World Government Data Store so no point duplicating the effort, instead I'll just point to...


...for a catalog of a lot of different country and city level Open Data Initiatives.
(It's not UK based, though it does seem to focus on English-speaking countries.)

At time of edit, it contains data for UK, US, Australia, Canada, New Zealand, and Basque Spain.

One thing not listed on there but worth mentioning is the Ordnance Survey UK mapping data.

  • The Guardian are also in the nice habit of providing the data which is referenced in their stories much of the time. – Jon Hopkins Nov 17 '10 at 14:56

There is data all over the place of every type. Best approach is to figure out what type of data you need, find a website that has it, and see if the site offers an API. However, here are some general sources:


The Open Data Protocol site lists a number of live oData services on its Producers page.

edit> StackExchange has an oData service listed there.



New York Times API


For a comprehensive catalog of US government data and supported formats, look here: http://www.data.gov/


New York City has a number of free MTA transit data feeds.

There's also a lot of other interesting public data sets in NYC such as restaurant health inspection data.


Somebody asked pretty much the same question on Reddit Compsci a while back... here's what I had to say then. I think it all still stands.

Poke around some of these sites, I'm reasonably sure there's something there to catch your interest.

Depending on what you're trying to do, there are tons and tons of datasets out there. One that's fun to play with, but might or might not be relevant to you, is the Enron Email Dataset. It's the result of a LOT of internal Enron corporate email being subpoenaed and released to the public back during the big Enron scandal.

And if you can't find exactly the data you want, don't underestimate the possibility of writing your own crawler/scraper. Depending on what data you want, it may be fairly straightforward to just crawl the web for your own dataset. There are all sorts of tools - from wget to apache droids - for helping you programmatically retrieve information.


Calgary Public Data Catalogue has some stuff from the city of Calgary, Alberta, Canada that is freely available.

Open Data and Internet Democracy Tools workshop was an event held in Calgary last Saturday about using this data, just as something to disclose.


Water Data

You can use NOAA to retrieve massive amounts of data to play with. I've used it several times and the API isn't half bad. If you don't care about what and simply how much that's where I would go.


Windows Azure Marketplace - although as of now, most data sources say 'coming soon'


For those who do AWS, Amazon Public Datasets might be of interest.


France recently opened an open data website

Edit: Paris did too

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