An integration engineer is responsible for developing solutions that an organization needs. The solution itself can be very vague and will depend on a number of factors such as what the industry the organization is in. This can vary from creating custom software for a specific need to developing custom hardware and machinery.
An integration engineer often plans, designs and implements the integration process. This can also include creating documentation for the process so that future managers and engineers know how to solve potential issues.
The process often starts by communicating with the client to see what their needs are. This eventually leads to test plan specifications and working with clients through analysis and design of the solution that is to be integrated.