Do you need an SDK for your API? »

In our last couple API strategy workshops, we've had good discussions on a common question for API providers - do you need to offer an SDK (software dev kit) for your API?

In this context we defined an SDK as going beyond offering an API to include platform-specific code that developers use in their apps to invoke API operations, also including the source code, and documentation that developers might need. Here's what we came up with:

Reasons to consider an SDK:

Speed adoption on a specific platform - for example Objective C SDK for iPhone.  Lots of experienced developers are just starting off with objective C+ so an SDK might be helpful.

Simplify integration effort required to work with your API - If key use cases are complex or need to be complemented by standard on-client processing. 

An SDK can help reduce bad or inefficent code that might slow down service for everyone.

As a developer resource - Good SDKs are a forcing function to create good source code examples and documentation.  (See some good examples here and here. )

To market your API to a specific community - you upload the SDK to a samples or plug-in page on the platform's exisitng developer community.

Reasons you might not need an SDK:

If your API is designed for adoption -  standards-based, well documented, etc.. developers may be able to get rolling without a client SDK.

Resources - it's tough to do a SDK for each platform you target, you'll have to pick carefully. Also, it can be time consuming and expensive to create SDKs (tip: maybe packaging up internal samples or test cycles can kickstart things)

Maintenance and versioning - convincing clients to upgrade to the newest version can be rough. Also, capturing the "local flavor" of each language you support can be a challenge.

Complexity -On each platform there might be use cases you don't expect, like keeping application-level secrets off clients, debugging, etc.

More is not necessarily better - fewer, more well-documented, code-level samples can often be the best resource. Facebook provides Android, C#, iPhone, JavaScript, PHP, and Python libraries (all documented differently), but Twitter supplies none. Facebook has more resources but still struggles a bit at times.

Our view: whenever possible, forget the SDK, and spend the time making your API better and more useable, and give good API resources such as example code.  

Agree or disagree?