What is the workflow when multiple developer are working with SST. Do each developer need separate AWS account, or they can use same AWS account with different IAM user.

Both work. If you're going to use the same AWS account you can do something like this

sst start --stage $USER

So if both developer are running

sst start --stage $USER

at same time it won't conflict. I mean dev1's event doesn't trigger lambda in dev2's local!?

Correct, if they have different user names

@thdxr Yeah that’d be neat! We can also parse the username from the Arn:

$ aws sts get-caller-identity
{
    "UserId": "AIDAIHW56K6VNFT4XPI2W",
    "Account": "112245769880",
    "Arn": "arn:aws:iam::112245769880:user/frank"
}

cool I'll write an issue