Our experience is in both apps and services. Examples of projects previously undertaken are given below.
Confluence upgrade and "pluginisation"/modernisation of their customisations. Integration of Atlassian Confluence with IBM Connections (now HCL Connections).
Build out of Atlassian Jira/Confluence developer docs and code e.g. for soy templating.
Huge multi-version & multi-language documentation site based on Atlassian Confluence.
Build intranet site based on Atlassian Confluence with many custom features including partial page templates.
Migration/consolidation of Atlassian Jira and Confluence instances.
Partner collaboration portal based on Atlassian Confluence.
Atlassian Confluence upgrade & custom development.