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Speedscale on a VM/EC2


  1. Speedctl is installed
  2. Docker is installed

Setting up local capture

Run speedctl install, select the Traditional server / VM flow and subsequently the Capture traffic and forward to Speedscale Cloud option. This will output a manifest file and a command on how to run it with something similar to docker compose --file speedscale-docker-capture.yaml up -d .

Now you have to configure your application to use the socks proxy running on *:4140 on your server, and configure it to trust the local certificates.

To test out the capture mechanism, you can make requests as you normally would but using localhost:4143 instead of the port your app is serving on.

Setting up global capture

The steps above setup an inbound proxy on port 4143 that forwards requests to your app but so far we've only captured request explicitly going to that port. To capture all existing traffic going into your app, you'll need to edit your load balancer. For this guide, we'll use AWS's ALB but the same steps translate to other types of load balancers and cloud environments.

Create a new target group/backend

Target Groups

We have an existing target group going to our app which serves on port 8080. We're going to create a new one with identical settings, the only difference will be the port 4143.

Make sure to configure the health check correctly, it should be identical to the existing one.

Target Groups

Check the security groups

Make sure the security groups/firewall rules for the load balancer and the VM allow traffic to flow between them.

The inbound group for the EC2 should allow traffic on 4143

Security Group

The outbound group for the ALB should allow traffic out to 4143 as well

Security Group

Modify the listener


We have an existing listener where HTTP traffic is forwarded to our listener called user that hit our app directly. We're going to edit this so that the load balancer forwards traffic to our new target group.


That's it! Now all traffic will be forwarded to the Speedscale proxy and be available for analysis

Analyze Traffic


You should be able to see traffic in the Speedscale UI after a few minutes and now you can using this traffic to create a snapshot.

Replaying Traffic

Replaying traffic starts by creating manifests similar to the capture step above. Run speedctl install and choose the Traditional server/VM flow again that allows you to replay recorded traffic. When prompted, enter the ID of the snapshot you created.

This will generate a report which you can find on the reports page.


The speedctl install command is just a helper and environment variables like SNAPSHOT_ID and TEST_CONFIG_ID can be modified in the manifest file without regenerating it every time.