Create a platform for equity negotiation guidance

Hi all. I’d love some objective advice on what feels like a fair equity setup for a technical co-founder in a very early stage startup. It's an enterprise B2B startup in a very niche market outside of the Western Countries is all I can share. # # Background Right now it’s just the two of us. He started the company and is driving the overall vision, strategy, fundraising, partnerships, and customer relationships. He’s been in the market for almost 10 years and has the relationships that helped get things started, including bringing in the first potential customers. I joined about four months after he started working on it to build the product and handle the technical side. This is the first time we’ve worked together. Over the last three to four months we’ve been collaborating closely and are now trying to formalize a co-founder agreement. The company is still very early, but there are some early signs of traction with a few potential customers that came through investor referrals. Before I joined, he had already done a lot of the groundwork, including regulatory preparation and getting the initial relationships in place. # My Role My main responsibility so far has been building the product and platform. I’ve been taking the product ideas and turning them into a working system, figuring out the architecture and building the core pieces needed for an MVP. We collaborate on product decisions, but he generally sets direction based on what he’s hearing from customers and his understanding of the market. I focus on building the technology and giving feedback on what’s technically feasible. Most of the business side, including strategy, fundraising, regulatory work, and customer development, is handled by him. He’s also based in market where the business operates, while I’m based overseas. # Contributions So Far Over the last few months I’ve been working on the project unpaid while building the product. I’ve also contributed about $4k toward early operating needs and some lending capital, and I flew to the market at my own expense so we could spend some time working together in person. I don’t come from a traditional software engineering background. Over the past few years I’ve been experimenting a lot with chat gpt and have been using that to build and iterate on the platform. We’ve been able to get a rough MVP up and running. # Where Things Stand The company is still very early and the product is actively being developed. At this stage the business could technically run through manual processes with partners, although the platform would obviously be important for scaling. We’re now trying to figure out what a fair equity split should look like given the roles, timing of when I joined, and the stage of the company. # Question Curious how others would think about this situation. What kind of range would you consider reasonable for a technical co-founder here, and what factors would matter most in determining that?