Where to Find Logs

1. Appian Cloud: Navigate to Appian Designer > Navigation Menu > System Logs. You can also access them directly via the /suite/logs URL.
2. Self-Managed: Typically located in the <APPIAN_HOME>/logs/ directory on the application server.

Typically Logs

Design & Expression Errors

When a user encounters a "blue screen" or an expression fails, these are the logs to check:

1. Design Error Log (design_errors.csv): The most critical log for developers. it captures every expression error that directly impacts a user, such as interface crashes or rule failures.
2. Tomcat Standard Out (tomcat-stdout.log): The "Holy Book" for general platform debugging. It contains most technical errors generated by the application server.

Query Performance : To find out why a page is slow or a query is failing:

1. Data Store Performance Log (perflogs/perf_monitor_db_*.csv): Breaks down queries into three phases: Prepare (Appian generating SQL), Execute (Time spent in the DB), and Transform (Converting results back to Appian objects).

Advanced Monitoring (Appian 2026 Standards)

1. Appian Health Check: Always mention this first in an interview. It automatically analyzes all the logs above to identify high-risk findings and performance bottlenecks.

For details visit official Appian Docs