ngrok gives you a public URL to your laptop. FlurryPORT gives you one that keeps what arrives. If you are tunnelling mainly so a provider can reach your dev machine, the thing you actually want is the request, kept, and sendable again.
Settle this before you switch. ngrok is a general-purpose tunnel. If you need a public address for an arbitrary local service, if you are demoing a web app to someone three timezones away, if you want inbound access to a port that is not a webhook receiver, ngrok does that and FlurryPORT does not. FlurryPORT does one job: webhook traffic you want to keep and send again. Outside that job, keep the tunnel.
Close the laptop and the tunnel is gone, and so is everything that came through it. A capture is still there tomorrow.
Every developer gets isolated capture endpoints with scoped replay targets, so two people testing the same provider stop overwriting each other.
Replay sends the original bytes, so HMAC verification passes locally instead of failing the way a re-signed or pretty-printed payload would.
Replay the same event as many times as the bug hunt needs, without asking the provider to fire again.
Create an endpoint; copy its capture URL.
Point the provider at that URL instead of your tunnel.
Run flurryport listen and register a target on your machine.
Stop the tunnel. Everything from here is kept.
The details live in the CLI reference and on capture and replay.