The short answer
Federal court hears cases arising under federal law and disputes between citizens of different states with more than $75,000 at stake. A defendant sued in state court can sometimes move, or remove, the case to federal court.
Where it fits in your case
The court is chosen at filing. A notice of removal is generally due within 30 days after service.
What to expect
Complete diversity. No plaintiff may share citizenship with any defendant.
LLCs take the citizenship of every member, which often surprises clients.
Forum defendant rule. A diversity case generally cannot be removed if a properly served defendant is a citizen of the state where suit was filed.
Practical differences include pleading standards, scheduling, discovery rules, and jury pools.
What we need from you
Legal names, entity types, and state of incorporation or headquarters for every party, plus the full membership chain of any LLC.
Common misconceptions
“Federal court is always faster.” It depends on the court and the case.
“An LLC is a citizen where it was formed.” Not for diversity purposes.