Hey stranger is almost always a soft re-open. It is someone testing the water after a gap: an ex, a match who went quiet, or a crush who wants attention without admitting it.
The right reply matches their playful energy without looking too eager. Acknowledge the gap with humour, then give them something to respond to.
They opened light, so keep it light. A dry or overly serious reply kills the vibe. Tease the stranger framing right back.
Resist where have you been. It puts them on the defensive. Assume positive intent and keep it fun.
End with something easy to answer so the conversation continues instead of dying after one exchange.
It is usually a low-risk way to restart contact after time apart. It signals interest while leaving room to retreat if you do not respond warmly.
Be warm but not overeager. Match their playful energy, show you are glad to hear from them, and avoid grilling them about the silence.
Often yes, especially from someone you have dated or flirted with. Treat it as a green light to be a little playful back.