The first person to contact you from the company that acknowledges your application will generally remains your point of contact (POC) unless they explicitly tell you otherwise (“I’m going to hand you off to ____, they’ll take it from here.") Whether your initial POC is technical or not will depend on the type of business and the size of the company, which I’ll cover later.
Your POC is the person with whom you’ll discuss the interview process in detail: what’s the next step, who will you be meeting, what should you wear, and so on. You should feel free to ask them any sort of questions pertaining to the company culture and typical day at the company.
There have been lots of stories in our industry over recent years of applicants showing up for interviews in attire that some would deem inappropriate. While you certainly need to be comfortable while at an on-site interview, it’s also important that you fit in culturally with the company and also be yourself. Ask your POC what their typical dress code is like, and try to show up one step better. If you can’t determine what that is, “business casual” is usually a safe bet.
Try to find photos from the company or its employees on social media of pictures from around their office(s) to get a sense of day to day attire.
Typically, wearing “business casual” attire is very common, unless you know the business is more formal (usually banks, insurance companies, etc) at which point full “business professional” is expected.
Try to avoid accessories or other things that may distract interviewers from what you’re capable of doing. At the same time, you need to be your individual self. If in doubt, talk to your point of contact and ask their advice.
Ask your POC if you can bring your own laptop. More and more companies, especially startups and small companies, will usually allow you to bring your own laptop. While this question may start a discussion over what the on-site interview will entail and whether you will be writing code on a laptop, there are some important ideas about bringing your laptop with you.
Some companies will simply not allow foreign devices on their primary network, which is a legitimate concern for security. You can, however, offer to tether from your phone or ask if they have a guest wifi network.
I suggest bringing your laptop with you anyway, and to prepare ahead of time (and practice) a demonstration of several projects. To accomplish this in a very slick and practiced manner, have everything localized on your laptop (databases, js/img/css assets, etc). Try to have two or three projects ready to show, but have your framework of choice running in the background on different port numbers so you’re not fumbling around in a terminal starting and stopping different services. The goal here is to open your laptop and there’s your browser running project number one in its own tab, walk them through it, tell them how you built it and what was fun and challenging. Close that browser tab, and there’s project number two running in its own tab, ready to walk through and tell the same story. Close that tab and walk through project three. Close your laptop lid and you’re done. Powerful.
To pull this off, you have to have everything about your presentation practiced and perfected, but more importantly you need everything local on your laptop: localhost for database connections, localhost for asset loading and data bindings, and so on. Repeat after me: localhost all the things!
Your POC should give you very clear instructions on how to get to the company for your on-site interview. Double-check the instructions, how to get there, and take traffic and transit times into account to arrive early.
Be sure to ask about parking reimbursement if you need to pay for parking to get to their interview.