Azure Application Insights vs Skylight

Azure Application Insights is an Azure Monitor service for collecting and analyzing application telemetry. It combines alerts, metrics, logs, workbooks, Grafana dashboards, and investigation tools such as application maps, live metrics, transaction search, availability monitoring, failure analysis, and performance views. Usage analytics cover users, sessions, events, funnels, flows, and cohorts. For.NET applications, diagnostics include profiling and a snapshot debugger for exceptions. Microsoft recommends the Azure Monitor OpenTelemetry Distro for most code-based server-side scenarios; browser telemetry uses the Application Insights JavaScript SDK. Setup paths cover web apps, virtual machines, JavaScript apps, Azure Functions, Kubernetes, and AI agents. Telemetry is stored in a Log Analytics workspace, and the service can work with applications hosted outside Azure. A daily ingestion cap can stop excess collection until the next UTC day, while sampling can reduce volume. The pricing page lists 90 days of no-charge retention, with longer retention charged by retained data volume. Ingestion is usage-based, with the first 5 GB per month per billing account free.

Skylight is a cloud profiler for Ruby and Rails applications, available through API, Linux, macOS, and web platforms. It ranks endpoints by “agony,” combining popularity with response time, and plots deployments against performance so teams can relate code changes to results. Supported Ruby frameworks include Rails, Sinatra, and Grape. Skylight analyzes Sidekiq, DelayedJob, and ActiveJob background queues, and can flag allocation-heavy code and repeated queries. Endpoint timelines present aggregated, sanitized SQL queries. GraphQL queries are grouped by name in the dashboard and endpoint event sequences. A weekly report identifies improved endpoints, slowdown warnings, and endpoints that declined over six weeks. Each account includes 100,000 free traces per month. Paid tiers start at $20 a month and adjust to monthly trace volume across apps. A 30-day trial is available without a credit card. Open-source apps may apply for free public reporting. Communications are encrypted, and access to customer information is limited to selected personnel and contractors.