Most apps designed to bring people together are also designed, more quietly, to keep you on the app. There’s a reason — engagement is how social products are valued, and the way to keep people engaged is to keep them inside the loop. Notifications get sharper. Feeds get longer. Saying yes gets easier than saying no.
This is fine for some kinds of products. It’s a problem for the simple thing of asking your friends if they want to come do something with you.
Inviting is asymmetric work. The friend who plans things — and most groups have one — is the one who notices that nobody’s seen each other in a while, picks the place, sends the text, fields the half-replies. They do this not because they’re owed something for it, but because they want to see their friends. They also know, with each new ask, that they’re trading on the goodwill of people who may not feel they have the same standing to refuse.
The standard fixes — the group chat, the events platform, the calendar invite — replace one kind of friction with another. Group chats reward the loud. Event platforms turn casual hangs into productions. Calendar invites are for meetings.
Perihelion makes one structural choice and lets it ripple. The choice: subscribers opt in once, on their own terms, and decide for themselves how loudly they want to hear from a given organizer. Every invitation after that is something they already agreed to receive. Three commitment tiers — “just an idea,” “I’ll go if you will,” “I’m going — join me” — let a casual ask travel as casually as the asker meant it.
What this redistributes is agency. The organizer is freed from feeling like a burden, because the invitee always has the structural option of saying nothing. The invitee gains the standing to decline without it being a weight on the relationship. Both sides get breathing room they didn’t have before.
This is also a product designed to be put down. There’s no feed to scroll, no streak to maintain, no metrics to chase. Notifications come exactly the way each subscriber asked — text, email, or a single daily digest. When the plan you wanted to make has been made, the right thing to do is close the tab.
It works for the friend group you’ve had since college. It also works for the people you’ve met recently and want to know better — the new neighbor, the colleague you started running into at the same coffee shop, the friend-of-a-friend you got along with at a dinner party. The architecture treats those baby friendships with the same care as your decade-long ones, because the same structural awkwardness keeps them small. Inviting somebody you barely know to do something casual is one of the highest-friction asks in adult life. Reducing that friction is a good in itself.
Perihelion will not become an attention business. It will not run ads. It will not sell user data. It will not train AI models on what people do here. It will not grow a marketing team or a content calendar or an engagement loop. The whole point is to be a small useful thing that mostly stays out of the way, and to be the kind of thing you’d be glad a friend told you about. If at some point this stops being true, the thing has failed in the only way it can fail.
Built by Sarah Lewis. Open source. Non-commercial. If it’s useful to you, that’s enough.