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FAT Client · /// Workload-based

Test the desktop apps the rest of the business actually depends on.

LoadGen runs thick-client and FAT-client desktop apps via the generic wizard with LocalClient technology — workload-based .lgs scripts, Full agents (port 4840), and continuous UX validation. No brittle UI macros.

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The Local Client technology runs a local desktop application on the LoadGen agent machine, without a remote protocol. Use this for workloads that don't require remoting.

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The Problem

Desktop apps drive the business. Nobody tests them under load.

Web has Playwright. APIs have OpenAPI. Desktop apps have brittle UI macros and prayer. The business pays the cost.

Desktop apps that nobody load-tests, and everyone depends on.

The legacy line-of-business app that runs payroll. The thick client behind the trading desk. They drive the business and they’re tested by exactly nobody under load.

Scripts that rot the moment a UI label changes.

AutoIt, AHK, hand-written wrappers — every UI tweak breaks the test. Maintenance overhead exceeds the value before the second release.

No way to compare a desktop app against itself across versions.

When the Citrix-published version outperforms the local install, you have a hand-wave hypothesis instead of a measurement.

How LoadGen handles FAT clients

Author · Deploy · Execute · Monitor.

Four motions, every one workload-based — not UI-macro-based. Same engine handles load, functional, and continuous monitoring.

Author

Generic wizard with LocalClient technology — workload-based scripts, not brittle UI macros. Captured once, replayed across versions.

Deploy

Full agents (port 4840) install, manage, and run thick-client sessions on real Windows hosts. Install, Uninstall, Reboot as batch operations.

Execute

Versioned .lgs workloads (Minor / Major / Patch) drive every test — desktop session lifecycle handled per-host, not per-script.

Monitor

Continuous E2E UX validation re-runs the same scenario between releases. Drift surfaces before users notice.

Live · Generic Wizard · Local Client

Workload-based, version-controlled, UI-tweak-resistant.

The wizard captures the workload — not the cursor coordinates. UI label changes don’t break the test, and version-controlled .lgs files mean every release is a comparable measurement.

.lgs workloads
Minor / Major / Patch version control built in — each version is its own comparison anchor in the audit trail.
Full-agent batch ops
Install, Uninstall, Reboot, Reset, Lock, Unlock, Logon, Logoff, Kill — every desktop op handled per-host.
Slot management
Per-host slot counts measured against actual desktop apps — no overshoot, no undershoot.
One engine
Same wizard authors load tests, functional tests, and continuous monitoring — no separate toolchain per use case.

Outcomes · before / after

Test the desktop apps the rest of the business is afraid to ship.

Drawn from teams that adopted workload-based desktop testing for one release cycle.

Time to first FAT-client test

Before

8 days

After

4 hrs

−98 %
Hours per script update

Before

6 h

After

20 min

−94 %
Apps under measured load

Before

2

After

14

+600 %
Regression escape rate

Before

24 %

After

2 %

−92 %

Move desktop apps from "afraid to ship" to "measured to ship."

Author the first .lgs workload this afternoon. Run it on Full agents this week. Compare versions on the next release without rewriting a single macro.

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