Sometimes PM groups have software that can help pull comparable sales information (CoStar & Yardi). 

My day job is as a software developer and I've been looking to get into real estate for a while and have finally decided to take the plunge.

Does anyone know if there's a website that you can put in an address and it'll calculate how much it will rent for, estimate cap exp, mortgage, taxes, vacancy, etc.Could save me quite a bit of time to have rough estim...

This is something a property manager will have access to along with accounting software for managing the tenants.

Many of the good PM's will run monthly cash flow reports or give you access to their Property Management software. 

I am curious for those of you who manage some or all of your own properties, what softwares do you like for allowing online payments and taking service orders?

Yes separate bank accounts for each, then some bookkeeping software that tracks it all separately for you.

I’m a software engineer trying to get my foot into real estate investing.

Now you need to start preparing for marketing, showing, screening software and processes, selecting a tenant, Fair Housing, emotional support animals, collecting a deposit, disparate impact, local and state housing laws, Section 8, your lease agreement, late rent, unpaid rent, partial rent, bounced checks, etc.No worries!

Look at getting Deal Analyzer software.