As I said in an earlier post, the folks as Programmableweb.com announced the that the number of open APIs they track reached an unbelievable number—4000—in record time.
The published this graph showing the hockey stick growth rate:
Figure 1—Total Number of APIs
source: Programmableweb
So lets take quick look at the dynamics of this growth rate.
Phil Windley helped me out and here is what we came up with.
The data could be interpreted as a power law.
Phil used this: http://zunzun.com/Equation/2/Power/Power%20A%20Modified/
Here’s the data:
0, 0
8.5, 1000
10.5, 2000
11.25, 3000
11.75, 4000
Power law says: Y = aX^b
The fit says
a = 13.665
b = 1.618
So, by the year 2013, (X = 13), we’d expect: 7117.
2016 shows 30,000 APIs.
This is a nice steep curve.
Figure 2—Extrapolating the Numbers
source: Craig Burton and Phil Windley
But I am going to go out on a limb and predict that something even more dynamic is in play. If you look at Figure 3, you can see that somewhere between Oct. and Nov. 2010, the growth Netflix was enjoying took a serious turn for the better. Hits on the API went from 4 billion a month to 12 billion in 30 days.
Figure 3—Growth of Netflix API
source: Programmableweb
If I am right, I expect that we hit the 5000 API mark sometime in mid 2012. Then instead of just going on the power curve to 7117 APIs by 2013, the industry will experience an exponential skip—like the one in figure 3 for Netflix—the jump will go from 5,000 to over 10,000 almost over night. So that we will be way ahead of this ambitious curve shown in Figure 2.
I have no real data to support that. I just think the movement is about to jump the chasm from early adopters to early majority sometime in 2012.
Whatchout.

Thanks for the great analysis. If you're right, we have our work cut out for us!
Actually I'd say the number will be way more than 30k in 2016 (lots of work for you Adam!) – we're seeing more than 70% of the companies we talk to at 3scale have an API which is internal or partner private that are not yet listed in public directories (that's today), and almost without fail these have long term plans to open up more broadly. So you might need to reset the starting point number to (for exmple) 10,000 APIs today or more.
Great post – and it exactly mirrors our experience at salesforce.com – more than half of our traffic is now via the APIs rather than the browser, and the rate of uptake is only increasing as mobile apps take advantage of our REST APIs. We also see a large amount of outbound API traffic to Twitter, Facebook etc. In fact, I blogged just yesterday on integrating with Pusher for real-time updates – http://blogs.developerforce.com/developer-relatio…
Thanks Steven. I would love to talk to you about this. Give me a call at 801-369-5974 and lets discuss. I know these numbers are conservative. It's what I have in hand.
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