Performance testing environment showing load metrics and system diagnostics
Performance Testing & Optimization

Your system tells you
what it can handle.
Do you know
the answer?

Most systems fail under pressure that was entirely predictable. Coredev Nexus exists to find those limits before your users do.

We run structured load, stress, and endurance tests against real-world traffic models — then work through the findings with your team to make the changes that actually stick.

A different approach

Not a report dump.
A working diagnosis.

Most testing engagements end with a PDF. You get a list of findings, a severity table, and a follow-up call that trails off into silence. The bottlenecks stay in the system.

Coredev Nexus structures every engagement around two things most vendors skip: root cause clarity and a practical remediation path your developers can actually follow.

Root cause, not symptom lists

We trace slowdowns to their origin — whether that's a misconfigured connection pool, an unindexed query firing at scale, or a thread contention issue that only appears under concurrent load.

Fixes your team can ship

Every finding comes with a specific remediation recommendation — not a generic "optimize your database" note, but a concrete change tied to the exact component, query, or configuration that caused it.

A concrete case

An e-commerce platform, peak season, and a queue that wouldn't drain

System load testing dashboard showing request queue and throughput metrics

What the test found — and what the fix looked like

A retail platform was handling checkout traffic fine in staging, but degrading badly above 800 concurrent sessions in production. The assumption was database capacity. The actual problem was a synchronous inventory lock on every cart update — a design decision from three years earlier that nobody had revisited.

We ran a staged load sequence from 200 to 1,400 simulated users, isolated the lock contention using thread-level profiling, and flagged the specific service boundary where the bottleneck lived.

1,400
concurrent users tested
6
days to full diagnosis
1
root cause identified
The core problem

Systems that look fine
until they suddenly don't

The specific problem performance testing solves is not "slowness." It is the gap between how a system behaves at normal load and how it behaves when that load doubles, spikes, or sustains for six hours straight.

That gap is where incidents happen. Outages during product launches, degraded checkout flows on sale days, API timeouts that only occur when three services hit their limit at once.

Load spikes with no warning

Traffic events rarely announce themselves. A campaign, a press mention, or a partner integration can push you past your untested ceiling in minutes.

Staging environments that lie

Staging rarely mirrors production data volume, connection counts, or third-party latency. Tests that pass there frequently fail in the real environment.

Degradation that builds slowly

Memory leaks and connection pool exhaustion do not fail immediately. They degrade response times over hours — a pattern that only endurance testing reliably catches.

Professional standing

Signals that indicate
serious practice

Choosing a performance testing partner is partly about methodology and partly about whether they operate at the level your system requires. A few markers worth checking.

Coredev Nexus works with organizations that have real uptime requirements — where a degraded checkout or a slow API response has a measurable cost. Our practice reflects that context.

Oleksiy Varchenko, Lead Performance Engineer at Coredev Nexus
Oleksiy Varchenko
Lead Performance Engineer
Tool-agnostic testing

We work with k6, Gatling, JMeter, and Locust — selecting based on your stack and traffic profile, not on what we happen to know best.

Observability-first diagnosis

Every test runs alongside APM tooling — Datadog, Grafana, or your existing stack — so findings are grounded in real telemetry, not inference.

Cross-team coordination

We structure findings for both engineering and product audiences — technical detail for developers, risk framing for the people making release decisions.

Practical outcomes

After an engagement,
your team knows exactly where it stands

The goal is not a passing grade on a benchmark. It is a clear picture of what your system can handle, where it starts to degrade, and what the highest-priority fixes are.

That picture takes different forms depending on where you are in the product cycle — pre-launch validation looks different from post-incident review, which looks different from ongoing capacity planning.

Engineering team reviewing performance test results and optimization recommendations
Defined capacity ceiling

You know the specific user count and request rate at which your system starts to degrade — not an estimate, a measured threshold.

Prioritized fix list

Findings are ranked by impact and implementation effort — so your team can address the most consequential issues first without getting lost in a long backlog.

Repeatable test baseline

The test scripts, traffic models, and configurations we build stay with your team — so future regression testing does not start from scratch.

Before you engage

What makes an engagement
actually productive

Performance testing produces better results when certain conditions are already in place. This is not a barrier — it is an honest description of what we need to do useful work together.

If some of these are not yet in place, that is worth knowing before we start. We can discuss what a realistic scope looks like given your current setup.

A test environment that reflects production data volumes — not a minimal seed dataset
Access to application-level metrics — response times, error rates, and at least basic infrastructure telemetry
A developer or architect available for a technical briefing before testing begins
Clarity on the traffic scenarios that matter — peak load estimates, critical user paths, or known failure points
Realistic expectations — meaningful optimization takes iteration, not a single test run
Already have some findings?

If you have run tests before and have existing reports, bring them. We can often build on prior work rather than starting from scratch — which shortens the engagement and focuses effort on what is actually unresolved.

Not sure where to start?

A short scoping conversation is enough to figure out whether your system and situation are a good fit for what we do. No commitment required — just a clear picture of what you are dealing with.

Start a conversation