u/Massive_Rabbit2064

Hey everyone,

I'm building a proximity-based payments app where users can discover other users nearby in real time.

My current approach is pretty straightforward:

• Users periodically send their GPS coordinates over Socket.IO.
• The backend keeps track of online users.
• Whenever someone updates their location, I calculate the distance to every other online user and return only the nearby ones.

I was planning to use the Haversine formula, but I recently came across Vincenty's formula and started wondering if that's the right approach.

My main questions are:

• Is Haversine sufficient for a 50–100m radius?
• At what scale does comparing every user become a bottleneck?
• Do production apps use geohashes/spatial indexing first and then calculate distances?

I'm trying to keep the MVP simple while avoiding a design that won't scale. I'd love to hear how you'd approach this or how similar systems are built in production.

Hey everyone,

I'm building a proximity-based payments app where users can discover other users nearby in real time.

My current approach is pretty straightforward:

• Users periodically send their GPS coordinates over Socket.IO.
• The backend keeps track of online users.
• Whenever someone updates their location, I calculate the distance to every other online user and return only the nearby ones.

I was planning to use the Haversine formula, but I recently came across Vincenty's formula and started wondering if that's the right approach.

My main questions are:

• Is Haversine sufficient for a 50–100m radius?
• At what scale does comparing every user become a bottleneck?
• Do production apps use geohashes/spatial indexing first and then calculate distances?

I'm trying to keep the MVP simple while avoiding a design that won't scale. I'd love to hear how you'd approach this or how similar systems are built in production.

Someone did a phenomenal job with the ₹370 biryani meme.
First, girls started paying on dates.
Now we need someone to do the same for "alimoney" and finally solve the other half of the internet's relationship debates.

One viral post. One economic reform at a time.

PS: ₹370 biryani waale bhai ne toh samaaj sudhaar diya. Ab Alimoney ke liye bhi koi mahaan aatma aage aaye. 😂

Someone did a phenomenal job with the ₹370 biryani meme.
First, girls started paying on dates.
Now we need someone to do the same for "alimoney" and finally solve the other half of the internet's relationship debates.

One viral post. One economic reform at a time.

PS: ₹370 biryani waale bhai ne toh samaaj sudhaar diya. Ab Alimoney ke liye bhi koi mahaan aatma aage aaye. 😂

Not promoting anything, just wanted landlord perspectives because I started thinking about this after helping a friend look for short-term housing recently.

A lot of units seem to sit vacant for anywhere from a few days to a few weeks between tenants while turnover, cleaning, repainting, repairs, showings, etc. are happening. At the same time, there are always people searching for cheap temporary stays for things like work relocation, hospital visits, internships, exams, or being stuck between leases.

It made me wonder whether there’s any realistic scenario where landlords/property managers would ever allow very short temporary occupancy during vacancy periods instead of letting units sit completely empty.

I’m not talking about Airbnb-style party rentals or luxury vacation stays. More like basic short-term occupancy with verified guests and minimal expectations.

The more I think about it though, the more it sounds like an operational/legal nightmare:
insurance, liability, squatter concerns, local STR laws, damages, scheduling conflicts with incoming tenants, cleaning coordination, bad guests, neighbors complaining, etc.

So from a landlord perspective:
Would the risks completely outweigh any possible income?
Or is this something some owners already quietly do in certain situations?

I’ve been thinking about the period where units sit vacant between tenants. In a lot of cases it’s days or weeks of zero occupancy while owners are still covering utilities, maintenance, cleaning, turnover work, etc.

At the same time, there are people constantly searching for temporary stays — students, workers relocating, hospital visitors, exam travelers, people between leases, backpackers, and so on — but hotel and Airbnb pricing has become unrealistic for many of them.

So I started wondering whether there’s any realistic model where vacant units between leases could temporarily serve as very basic short-term housing instead of sitting completely unused.

Not luxury stays or party rentals. More like:
clean unit, verified guest, basic necessities, short duration, affordable pricing.

But the more I think about it, the more I realize the operational side is probably where this gets ugly:
verification, liability, damages, insurance, local regulations, neighbor complaints, cleaning coordination, bad guests, scheduling conflicts with incoming tenants, etc.

From an owner/property management perspective, would something like this ever be worth the trouble operationally, even if it generated partial income during vacancy periods?

Or do the risks and management overhead completely outweigh the upside?

Lately I’ve been thinking about how many apartments sit empty between tenants for days or even weeks while people searching for short stays still end up paying ridiculous hotel or Airbnb prices.

So I started wondering whether there’s an actual business opportunity in “vacancy-gap rentals” — basically temporary stays in already-vacant apartments between leases.

I’m not talking about luxury stays or premium travel experiences. More like clean, verified, affordable temporary housing for students, workers relocating, exam travelers, hospital visitors, backpackers, etc. People who care more about affordability and safety than luxury.

From the owner side too, even partial income during vacancy sounds better than leaving a property completely unused.

At first the idea sounded pretty straightforward in my head, but after reading discussions in other subreddits I realized the operational side could become brutal:
trust/verification, damages, cleaning turnover, regulations, liability, neighbors complaining, fake bookings, scaling city by city, and so on.

I’m also not really approaching this from a “maximize profit” angle. I’d honestly be happy if the model could sustain itself operationally while making temporary housing cheaper and more accessible for people who actually need it.

So I wanted to ask:
Does this sound like an actual underserved niche?
Or does this fail for reasons Airbnb and others already discovered years ago?

Would genuinely appreciate blunt feedback from people who’ve built businesses or dealt with housing operations before.Could vacancy-gap rentals work as ultra-budget housing?

I will not promote, just wanted opinions on something I’ve been thinking about lately.

I noticed a lot of apartments stay empty between tenants for days or even weeks sometimes, while people looking for temporary stays still end up paying crazy hotel or Airbnb prices.

So I was wondering if there’s any realistic way vacancy-gap rentals could work.

I’m not talking luxury stays or fancy setups. More like basic temporary housing for students, workers relocating, people visiting hospitals, exam travelers, backpackers etc. Just clean, safe and cheap.

From the owner side too, earning at least something during vacancy sounds better than the property sitting completely unused.

The more I think about it though, the more it sounds like an operational headache lol. Cleaning, damages, trust, fake bookings, neighbors complaining, legal stuff, liability and all that.

I’m also not thinking of this as some giant money-printing startup idea. If something like this ever existed, I’d honestly just want enough to keep the operations/infrastructure running while making short stays cheaper for people who actually need them.

Does this sound realistic at all or am I underestimating how painful this would be?

Been thinking about a possible rental model and wanted honest feedback from people who manage short-term rentals/properties.

A lot of apartments seem to sit vacant between long-term tenants, renovations, or seasonal demand dips. I was wondering whether there’s room for a managed medium-stay model (roughly 1–3 week stays) where verified occupants can temporarily use these properties instead of them sitting empty.

The idea would focus heavily on:

• identity verification
• managed check-in/check-out
• post-stay inspection/cleaning
• accountability for damages
• reducing downtime for owners

I’m mainly trying to understand:

• Is vacancy between tenants actually painful enough to solve?
• Would owners ever trust something like this?
• What operational/legal issue would kill this idea immediately?

Would appreciate honest feedback from hosts/property managers.

A lot of apartments and houses stay vacant between tenants for weeks or even months. At the same time, there are people who want medium-length stays (like 1–3 weeks) in a city/country but hotels and Airbnbs can get expensive fast.

What if there was a managed platform that:

• lets property owners earn during vacancy periods
• offers verified short/medium stays
• includes inspections/check-in verification between guests
• focuses more on remote workers/travelers rather than party-type stays

Originally I was even thinking about splitting occupancy/time slots to reduce costs further, but I’m not sure if people would actually be comfortable with that.

As a traveler or property owner:

• would you ever use something like this?
• what would immediately stop you from trusting it?
• what would make it feel safe/professional?

Would love brutally honest feedback.