The use of GIS for planning, emergency management and modeling typically uses desktop GIS, which can be costly, complicated and with large overhead that makes its use daunting for the average user. ESRI's ArcEngine allows programmers to build custom ArcGIS applications for specific uses that can lessen the learning curve, target a specific market and deploy to many users either in the field or in the office for use in hazard mitigation and response at a lower cost than a full ArcGIS deployment. NOAA's Center for Tsunami Research and NOAA's Coastal Data Development Center have created an application to assess the impact of tsunami hazards in coastal communities for the United States and Pacific Territories using ArcEngine that allows the user to modify the inputs to determine the impact from different scenarios using a combination of Standing Inundation Model (SIM) results, census information, bathymetry/topography, community infrastructure with the option of adding more data as the user needs change. We will explore the relative merits of the ArcEngine application versus using a web-based ArcGIS Server solution for decision support.