Maple field manual
Operate from evidence.
Plain-English foundations and hands-on investigations for engineers running production software. Start with APM, then go deeper into observability, OpenTelemetry, and the signals behind a useful answer.
02 · Foundations
Build the mental model
Read in any order. Each guide answers one durable question without assuming a vendor or stack.
What is observability?
Understand traces, logs, and metrics, and why correlation matters more than collecting each signal in isolation.
What is OpenTelemetry?
Learn how vendor-neutral instrumentation keeps telemetry portable across languages, collectors, and backends.
Best open-source observability tools
Compare the leading open-source options by architecture, signals, license, operating cost, and best fit.
What is Apdex?
Read the score that turns response times into one satisfaction number, choose the target T behind it, and know when it beats a p95 alert.