Capacity Management as a Continuous Practice

A monthly retainer maintaining your load test suite, running capacity checks on architecture changes, forecasting your next scaling ceiling, and keeping CI/CD performance gates aligned with your evolving system.

Duration: Ongoing Team: 1 Senior Load Testing Engineer

You might be experiencing...

Load test scripts from last year are broken because the API changed and nobody updated them
You run a load test before big launches but have no visibility into capacity between them
Your traffic is growing 15% month-over-month but you don't know how close you are to your next ceiling
New services get deployed without load testing because there is no established process for it

A load testing retainer solves the fundamental problem with periodic load tests: your architecture changes continuously, but point-in-time testing only tells you about the architecture at the moment you tested. A load test suite that is not maintained becomes stale within weeks as API contracts change, new services are added, and infrastructure is modified. Monthly maintenance keeps the suite accurate and the results meaningful.

The highest-value deliverable of the retainer is the 6-month capacity forecast: by combining measured capacity ceilings with your current traffic growth rate, we produce a concrete projection of when each ceiling will be reached and what infrastructure action is required to address it. This transforms capacity planning from a reactive discipline (we hit the wall, now we fix it) into a proactive one (we will hit the wall in 3 months, here is the infrastructure investment required, here is the lead time).

CI/CD gate maintenance is operationally important and frequently neglected: performance thresholds that made sense at 1,000 req/s may need adjustment at 10,000 req/s, and new endpoints need gates added as they are deployed. The retainer includes ongoing gate maintenance, so the CI/CD performance signal stays accurate and actionable as the system evolves. A gate that always passes because its thresholds are out of date provides no protection — it only creates false confidence.

Engagement Phases

Week 1–2 each month

Monthly Suite Maintenance

We update load test scripts to reflect API changes from the previous month's deployments, add scenarios for new features, and retire outdated scenarios. We run the full suite and compare results against the previous month's baseline, flagging any performance trends.

As needed each month

Architecture Change Validation

For significant architecture changes (new services, database migrations, infrastructure scaling), we run targeted load tests to validate performance before and after. We maintain a change log of architecture decisions and their measured performance impact.

Week 4 each month

Capacity Forecast & Reporting

We deliver a monthly capacity report: current headroom at 1x, 2x, and 3x traffic, projected time to next ceiling based on growth rate, and recommended infrastructure actions for the coming quarter. We maintain a rolling 6-month capacity forecast.

Deliverables

Maintained load test suite (up-to-date with current API)
Monthly capacity headroom report
6-month capacity forecast with growth trajectory
CI/CD performance gates maintained and updated
Architecture change load test results

Before & After

MetricBeforeAfter
Capacity headroomUnknownMeasured monthly
Time to next ceilingUnknownForecast updated monthly
Load test coverage0%All critical paths covered

Tools We Use

k6 / Locust maintained suite Capacity forecasting models CI/CD integration

Frequently Asked Questions

How do you keep load test scripts in sync with API changes?

We subscribe to your API changelog (or review merged PRs monthly) and update affected test scripts within the same sprint cycle. For teams with OpenAPI specifications, we use contract-driven test generation to automate baseline scenario updates. Scripts that cover deprecated endpoints are flagged for review rather than silently broken.

What does the capacity forecast include?

The forecast combines your current measured capacity ceilings with your traffic growth rate (from your analytics) to project when each ceiling will be reached. It includes: current headroom at steady state, headroom at 2x and 3x traffic, projected date of next ceiling (with confidence interval), and recommended infrastructure action (add replicas, shard database, add caching layer) with lead time.

Is this different from having an SRE who does capacity planning?

Our retainer complements SRE capacity planning by providing the measured data that makes capacity planning accurate. Many SRE teams do capacity planning based on resource utilisation metrics and extrapolation — our load testing provides the ground truth about breaking points and bottlenecks that makes those extrapolations reliable. We often work alongside SRE teams, not as a replacement.

Know Your Scaling Ceiling

Book a free 30-minute capacity scope call with our load testing engineers. We review your architecture, traffic expectations, and upcoming scaling events — and scope the load test that will give you the data you need.

Talk to an Expert