{"head":{"title":"What Is APM (Application Performance Monitoring)? | OceanLab","description":"APM tools track how fast and reliably your app answers requests, down to the slow query or failing call. What APM covers, an example and common mistakes.","canonical":"https://oceanlab.in/glossary/apm"},"crumbs":[{"name":"Home","path":"/"},{"name":"Glossary","path":"/glossary"},{"name":"APM","path":"/glossary/apm"}],"slug":"apm","term":"APM (application performance monitoring)","aka":["application performance monitoring","application performance management"],"category":"Hosting and delivery","short":"Tools that measure how fast and how reliably an application handles requests, and show which part of the code or which call is slow.","body":[["An APM agent or SDK runs inside your app and records each request: how long it took, which database queries and external calls it made, and whether it failed. Dashboards then show response times, error rates and throughput, and let you open one slow request to see where the time went."],["APM is one part of ",{"href":"/glossary/observability","text":"observability"},", alongside logs and metrics. Modern APM is built on distributed tracing, which follows one request across several services."]],"why":["Users notice slow pages before teams do. APM shows which endpoint got slower after a release, which query needs an index and which third-party API is dragging the app down. It turns performance from guesswork into a ranked list of fixes."],"example":["After a release, an e-commerce checkout gets slower. The APM trace for a slow checkout shows the same product query running forty times in a loop. Batching it into one query brings the page back to normal."],"inBuild":["We add tracing from the first deploy, with a request ID that also appears in logs, and set alerts on response time and error rate for the few endpoints that matter most. Sampling keeps the cost of the APM tool in check as traffic grows."],"mistakes":[["Tracking averages only. The slowest one percent of requests is where users suffer."],["Sending every trace at full volume and getting a large monitoring bill."],["Alerting on everything, so real alerts get ignored."]],"related":[{"href":"/glossary/observability","label":"Observability","detail":"How well you can understand what a running system is doing, and why, from the data it gives off: logs, metrics and traces."},{"href":"/glossary/load-balancer","label":"Load balancer","detail":"A service that spreads incoming traffic across several servers, and stops sending traffic to any that fail their health checks."},{"href":"/glossary/cold-start","label":"Cold start","detail":"The extra delay when a serverless function or a new server instance has to start up before it can handle a request."},{"href":"/glossary/connection-pooling","label":"Connection pooling","detail":"Keeping a set of open database connections and sharing them across requests, instead of opening a new connection for each one."},{"href":"/glossary/autoscaling","label":"Autoscaling","detail":"Automatically adding or removing computing capacity, such as servers or containers, as the load on a system goes up or down."}],"tools":[],"links":[{"href":"/pricing/categories/observability","label":"Observability pricing","detail":"Monitoring and tracing prices, with sources."},{"href":"/pricing/categories/error-monitoring","label":"Error monitoring pricing","detail":"Error tracking prices, with sources."}],"sources":[],"legal":false,"updatedAt":"2026-10-25"}