No hay problema.
When to use
Use this when someone apologizes for a small mistake or expresses concern about a minor issue. It conveys that the situation is easily handled.
How it works
This phrase uses the impersonal form of 'haber' ('hay' - there is/are) negated by 'no'. 'Problema' is a masculine noun meaning 'problem'.
Register
This expression is common in everyday, informal conversations. While widely understood, it carries a friendly and relaxed tone.
Notes
Friendly response to a minor problem. Neutral everyday wording.