It is interesting to see how markets will welcome Windows Azure’s BizTalk Services (WABS) with it’s quite scalable pricing. In this post, I will do little comparison between WABS and on-premises installation prices. As there is a huge amount of variables that have an impact on pricing, comparison shall be only directional.
But first, lets introduce WABS: it comes in four editions:
You can also choose Pay-as-You-Go between 6-12 month plans. Pay-as-You-Go might be ideal for developer edition (about 432€ annually with pay-as-you-go model) and some special testing phases maybe. Otherwise is quite logical to use longer plans as integration platforms are not deleted and generated all the time. In my comparison, I’ll use 6-12 month plan price versus on-premises BizTalks with SQL Server standard, Software Assurance fees for BizTalk and SQL Server and monthly infrastructure cost estimation.
Before comparison let’s have look to Microsoft’s pricing instrument called BizTalk Unit.
“For BizTalk Service Standard and Premium, we provide scale out capabilities. One BizTalk Unit is the smallest deployment size, and you can scale out in terms of BizTalk Units. Each BizTalk Unit comes with certain compute capacity. For BizTalk Service Standard, you can scale out up to 4 BizTalk Units, and for BizTalk Service Premium, you can scale out up to 8 BizTalk Units.” 
Okay, seems bit like adding servers in virtual environment except Microsoft is taking care of the work. In addition, there are no headache of memory or CPU consumption as WABS scales with amount of EAI Bridges and amount of bridges using BizTalk Adapter Service.
Below is the feature list of each edition.
|High Availability*||Not available||Yes||Yes||Yes|
|Scale Out||no||no||Up to 4 units||Up to 8 units|
|EAI Bridges per unit||30||50||125||250|
|Number of connections using BizTalk Adapter Service||1||0||5||25|
|EDI Agreements per unit||10||0||0||1000|
* High Availability is a feature available by default in Basic, Standard and Premium editions. It implies having multiple VMs within a single BizTalk Unit for resiliency against hardware failures.
Following chart compares cumulative price estimations including before mentioned factors. What is not included is Azure bandwidth fees. Comparison is made between 2 x WABS versus 8 cores of on-site BizTalk with clustered SQL Server of 8 cores. This means that 2 units of WABS standard have total 250 Bridges with 10 connections using Adapter Services.