What is an API


Posted By: Thomas Shaw, 10:34pm Monday 23 March 2009

You may have heard the acronym "API" before, so what is it, and how it is used in recruitment. An application programming interface (API) is a set of programming instructions and standards for accessing a Web-based software application or tools. Software providers can release their own API to developers/clients/users, so they can develop and design products powered by the remote service.

An API is a software-to-software interface - NOT a user interface. With APIs, applications talk to each other without any user knowledge or intervention. Job boards, recruitment databases, payment providers & social networking sites all use some sort of API to communicate with each other. 

With APIs, the calls back and forth between applications are managed through a web service. Web services are a collection of technological standards and protocols, including XML (Extensible Markup Language), the programming language by which applications communicate over the Internet.

For example, if you post a job through JobAdder; the job advert is processed and posted to the job board via an API. During this process the API will check credentials, verify data and respond with information whether the job has been successfully posted or not.

The same process can be applied when you buy movie tickets online. When you enter your credit card details, the movie ticket Web site uses an API to send your credit card details to a remote application (bank) that verifies whether your information is correct. Once payment is confirmed, the remote application sends a response back to the movie ticket Web site saying it's OK to issue the tickets.

APIs and Web services are completely invisible to web site surfers and software users. Their job is to run silently in the background, providing a way for applications to work with each other in order to get the user the information or provide the functionality needed.

Software providers who release their API often do so as part of a larger software development kit (SDK) that includes the API, programming tools and other instructional documents to make the integration easier.

The image on the right shows the process of posting a job through the JobPortals network

Job boards and software providers have started integrating Twitter via the API to post jobs. In my previous blog post I wrote about how job seekers can use HashJobs and TwitterJobSearch to search for jobs. Both these sites use the API to search Twitters database.

Of course I could go into further technical detail, but recruiters should leave the integration of APIs to the experts who specialize in these areas.