Ramping VUs
Ramp virtual users over time to simulate traffic spikes in BrowserStack Load Testing.
Depending on your preferred method, select any one of the following to set ramping virtual users:
Configure Ramping VUs
Select Ramping VUs from the dropdown menu, and configure Ramp-up, Hold, and/or Ramp-down stages.

Each stage will have 4 parameters which will determine the shape of the load curve:
- Type: Select Ramp-up, Hold, or Ramp-down
- Duration: Specify the duration of the stage
- Start VUs: Specify the number of VUs at the start of the stage
-
Target VUs: Specify the number of VUs at the end of the stage
You can add additional stages as per your test requirement.
Configure Ramping VUs
If you want to gradually increase or decrease VUs over time, use the loadProfile config instead of duration. This approach lets you model realistic traffic patterns such as ramp-ups, peak holds, and ramp-downs.
- Under the
loadProfileblock, settypetorampingto enable staged traffic changes. - Under
stages, add one or more steps:-
type: rampincreases or decreases VUs fromfromtotooverduration. Result: VUs change linearly until they reach the target. -
type: holdkeeps VUs constant forduration. Result: VUs stay at the specified level without change.
-
- Keep stage durations realistic. Very short ramps can cause bursty load that is hard to analyze.
- Ensure your total
vusis high enough to cover the largest stagetovalue. If not, the test cannot reach the target VUs.
Validation rules:
- Each stage must include
type,from,to, andduration. - Use valid time units (
Xs,Xm,Xh). Example:45s,10m,1h5m. -
fromandtomust be non-negative integers and must not exceed the globalvuslimit. - Avoid overlapping or contradictory stages (for example, alternating rapid up/down ramps) unless you are testing resilience to bursty traffic.
loadProfile:
type: ramping
stages:
# Stage 1: Ramp-up from 0 to 20 VUs
- type: ramp-up
from: 0
to: 20
duration: 2m
# Stage 2: Hold peak load
- type: hold
from: 20
to: 20
duration: 5m
# Stage 3: Ramp-down to 0 VUs
- type: ramp-down
from: 20
to: 0
duration: 1m
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