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Resolving co-ownership and dev costs for custom equipment rental software

ŞŞerife D***Member
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Customer Relations Manager
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Law
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boutique agency
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Oct 2024
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380
#1

My partner and I run a business in Manchester renting out camera lighting, and audio gear to film and event productions. For two years, we've been running an off-the-shelf open-source rental platform on our own local server. The initial setup and core configuration were handled by an external developer for 4,500 pounds which we split equally from the business account.

Over the past year however, another 12,000 pounds was spent developing custom booking logic, security deposit tracking and barcode inventory modules—all driven and managed purely by my own efforts. My partner's take is: "This software is open source anyway, no one owns the code, we'll write off the costs as operating expenses, and if we split, we can both just take a copy and use it." I argue that these custom builds and the database schema carry distinct IP value within the company.

How should development costs be divided for custom software built on top of an open-source core? In the event of a partnership split, who legally owns the customer database the custom modules, and the system license?

OOsman T***Member
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Technical service technician
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Furniture manufacturing
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a company within a holding
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3
Most Helpful#2

Short answer: Even if the open-source core license remains public, any custom business logic, integrations, and database schemas built on top belong either to the company or to the party that funded the work. You need a written partnership agreement that separates the core code from proprietary modules and clearly outlines the funding model.

Open-source licenses (like GPL or MIT variants) generally apply to the core itself and publicly distributed versions. Custom barcode, dynamic pricing, and deposit modules that you run internally on your own server without distributing to third parties can be treated as standalone IP. Your partner's claim that "it's open source, so nobody owns it" is both technically and legally incorrect.

The 12,000 pounds you paid out of pocket must be formally accounted for on the books immediately. It should either be recorded on the balance sheet as a director's loan to be repaid to you as a priority from cash flow, or treated as a capital contribution that increases your equity share accordingly. In either scenario, the IP rights to the code should belong directly to the corporate entity, not to individuals.

In a breakup, your most valuable asset isn't the raw code; it's the booking history, pricing strategy, and client database. Any agreement you sign must include a non-compete clause preventing a departing partner from taking the custom modules and the proprietary database to launch a direct competing business in the same market, even if they walk away with the open-source core.

SSultan G***MemberCommunity member
Joined
Jun 2024
Message
153
#3

Your partner is taking the easy way out. They're hiding behind the "open source" excuse to get a free ride on your 12k investment. If the company isn't officially covering the bill don't just hand over that custom code; keep the dev agreement under your own name and simply license it back to the business.

edit: typed from phone, sorry for typos.

OOkan U***ExpertCommunity member
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Apr 2023
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286
#4

Check the core software's license type. If it's AGPL and you run it over a network for users, you might have an obligation to open-source your modifications. But if it's MIT, BSD, or Apache, you can keep the add-on modules completely closed source and register them as proprietary assets owned by the company.

JJale Ç***MemberCommunity member
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Nov 2024
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199
#5

Talk to your accountant immediately and have that 12.000 sterlin recorded as a director's loan to the company. That way as the company turns a profit, you get paid back first. And sign a quick two-line agreement stating that you retain the IP rights to the modules until the debt is fully settled.

İİlker K***VeteranCommunity member
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Nov 2023
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343
#6

To avoid future disputes, settle these three points: 1) Keep custom-developed modules in a separate repository from the open-source core. 2) Record the 12.000 sterlin expense in the official books as a shareholder loan. 3) Put it in the contract that in the event of a split, the customer database stays exclusively with the active operating company.

İİlknur E***MemberCommunity member
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Sep 2024
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128
#7

We went through a similar ownership dispute in our car rental business. When things came to a split the company was completely paralyzed for three months fighting over "who owns the software." You can always rewrite the code somehow but if you lose customer records and booking history the business collapses. Get it sorted out now.

Edit: asked below, I wrote the answer in the second message.

SSelin T***Member
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Intern
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Logistics
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300-person organization
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Doki · Corporate website · 2023

#8

people think open source means nobody owns anything but the real value is in the modules that plug that code into your workflow. make sure you get an invoice for the out-of-pocket money and book it to the company or you won't have a leg to stand on if you ever split up.

KKaanMember
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Product Manager
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May 2024
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96
#9

Did you have your partner's written approval or an email confirmation when spending that 12.000 sterlin? If you did it entirely on your own initiative, your partner could refuse to acknowledge the debt, arguing, "I never approved this, it doesn't bind the business."

SSelim C***MemberCommunity member
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Nov 2025
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53
#10

The exact same thing happened to us running an event equipment rental business in London. My partner wrote the code and I brought in the clients. When we split we ended up in court over code ownership and paid a whopping 8.000 sterlin in legal fees. Looking back, I really wish we had just drawn up a two-page notarized agreement right at the start.

TTülay S***MemberCommunity member
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May 2024
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408
#11

We need to take it step by step. Start with a small trial; don't commit to everything at once.

If I were you, I'd go this route.

NNeslihan K***Expert
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IT Manager
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Catering
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chain store
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Jan 2023
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40
#12

This is exactly what we experienced. The real issue isn't the number, but what it's based on.

If you're offering equity instead of salary, also state what you're offering in return. Correct me if I'm wrong.

OOya K***MemberCommunity member
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Aug 2024
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337
#13

Thanks a lot I'll try it today. Partnership isn't a decision to make without working together first.

Of course, it varies if your situation is different.

AAhmet H***Member
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sole proprietorship
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May 2024
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#14

I'm a small business, let me explain from my side. If you don't write this down from the start, it leads to arguments later.

If you have questions, write them; I'll answer as best I can.

KKoray S***MemberCommunity member
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#15

Let me speak from the other side; I'm on the supplier side. I mean valuation methods for exits must be defined by formula; "market value" isn't enough.

Of course it varies if your situation is different.

RRamazan A***MemberCommunity member
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Feb 2023
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34
#16

Here's how it went for us. When making a decision, first look at what data you have on hand.

Everyone rushing into co-ownership of software gets stuck at the same point. If you have questions, write them; I'll answer as best I can.

TTaner Y***MemberCommunity member
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Dec 2023
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#17

I agree.

NNecati S***MemberCommunity member
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May 2023
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#18

to get into the details: Just because everyone does it doesn't mean it's right.

proveen by experience.

DDoruk Y***MemberCommunity member
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#19

Timely topic.

BBeyza V***Member
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#20

Thanks a lot, I'll try it today.

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