Support

Need a hand? Start here.

Getting started

• SimLoad opens with the URL shortener scenario and its goal. Press Run to send traffic through the design and watch queues, latency, errors and cost change live.
• Pick another of the nine scenarios from Scenario, or start from scratch with File → New blank design and add components from the palette.
• Turn up Peak load to stress the design. The Insights panel explains what's breaking and how to fix it. The Capacity planner can size the design for you.
• Press ? in the top bar to bring back the welcome card at any time.

Common questions

Where are my designs saved?

On your device. SimLoad autosaves the current design in the browser (or in the app) and restores it next time. To keep a copy elsewhere or move it to another device, use File → Export design and later File → Import…, or send yourself a share link.

How do I share a design?

Choose File → Copy share link. The link holds the whole design, so whoever opens it sees exactly what you built. In the apps, the link points at simload.webappslab.com so it works for anyone.

Exporting or the PDF report does nothing

On the website, check that your browser allows downloads and pop-ups for this site. The printable report opens a new window. In the apps, exports open your phone's share sheet and the report opens the print dialog, where you can choose "Save as PDF".

Does it work offline?

Yes. The apps include the whole simulator and never need the internet. The website saves itself on your device after your first visit and then works without a connection.

How accurate are the numbers?

SimLoad uses queueing models and sampled requests. It's good for comparing designs and finding bottlenecks, but the figures are estimates. To match a real system more closely, use Validate mode to calibrate components from measured latency or load-test results (k6, Gatling, JMeter or CSV). Cloud prices are list prices and change over time. See the Terms of Use.

It's hard to use on a small screen

On phones, SimLoad stacks the panels and you scroll the page. Turning the phone sideways, or using a tablet or computer, gives the canvas more room.

How do I start over?

File → New blank design clears the canvas. To remove everything SimLoad has saved, clear this site's data in your browser, or the app's storage in your phone's settings. See the Privacy Policy for what is stored.

Requirements

• Website: a recent version of Chrome, Edge, Safari or Firefox. A computer or tablet is best for building designs.
• Android app: Android 7.0 or newer, with an up-to-date Android System WebView
• iPhone and iPad app: iOS 15 or newer

Report a problem or suggest an idea

Email pavan@webappslab.com. It helps to attach the design (File → Export design) and describe what you expected to happen.