言っとくけど

just so you know

→ 言う
phrase Uncommon #11,613
just so you know An informal contraction of 言っておくけど, used to introduce a warning, clarification, or important point. It often has a tone like “I’m telling you now, but…”
JA: 言っとくけど、明日は仕事だからね。
EN: Just so you know, I have work tomorrow.

念のため言っとくけど友達だけだよ

Just so we're clear, we're only friends.

言っとくけどあなたのために説明したのよ

Just so you know, I explained it for your sake.