# How much does it cost to develop an integration?

We’re often asked how we go about estimating an integration project and how much an integration costs. In a previous article entitled "How much does an Integration Cost?” we look at the various cost elements to consider when calculating the TCP (Total Cost of Ownership) of an integration solution.

In this article, we offer some guidance on how integration experts and customer success teams typically estimate the development costs (including design, development and module testing). Note however, the estimates provided relate only to development costs. Additional line items such as subscription costs, cloud costs, implementation or operational costs must be estimated separately as highlighted in article previously mentioned, "How much does an Integration Cost?"

We find ‘T-shirt sizing’ a useful measure to describe the complexity of an integration. Years of experience enables us to predict how complex particular types of integration will be and therefore how much development effort will be needed. We can then group these under different ‘T-shirt sizes’.

Here are our "T-shirt size" definitions and their associated characteristics (defined around set of assumed complexities):

**S -**Low complexity:

Typically 1-3 integration steps, simple data mappings, often uni-directional message flows, quite often file based integration.**M -**Medium complexity:

Several integration steps, some protocol mediations, some data enrichments or cross-referencing needed**L -**Larger complexity:

Numerous integration steps with orchestration, a mix of different integration patterns, some state-handling, complex format/ data mappings, secure integrations with encryption**XL -**High complexity:

Quite a few / various integration steps with orchestration, different integration patterns and integration styles involved, complex format/ data mappings with "on-the-fly" calculations or aggregations, secure data exchange across network boundaries**XXL -**Extreme complexity:

Unknown complexity or high complexity with many unknowns, many integration steps, complex orchestration with several different routes / flows / paths, complex requirements regarding data security such as pseudonomizing data, integration with monolithic or highly customized enterprise applications (i.e. SAP, SAP IS-U)

For each of the categories, we analyzed the average development effort (design, development, module-testing) needed in person days (PD):

**S:**3 PD**M:**5 PD**L:**10 PD**XL**: 20 PD**XXL**: 50 PD

So, to quickly get to an estimate, we follow the following steps:

- Identify and list each of the integrations, data flows or message exchanges to be developed
- Categorize each of the identified integrations using the "T-shirt sizes". We recommend that XXL should always be used when SAP, SAP IS-U or similar systems are involved
- Summarize the effort in person days
- Add 40% to the estimate for analysis, design clarifications, API specification
- Sum up 3 and 4 and you have your estimated time for development

If you would like to see the Excel template we use for a more detailed estimate, please feel free to reach out to us.