I am not a founder but worked at various places that did this and I don’t think there is a simple answer except be very resourceful!
High gross margins feed into costs going into future sales and future development. Zero profit because you are reinvesting. Very tax efficient too!
Also see if there are research tax breaks in your country.
It means being lean and scrappy the whole time (no fluff or big rewrite it in Rust type activity). OTOH the successful companies were not cheap with salaries but not extravagant either. But they aim to get the top 10% cream working for them.
Hate to say it but you need to be strategic and good. Maybe see if you can pay for advice too from someone who has done it in your space.
I haven’t given you an answer! But the main thing I see is a sales system that gets tuned. Sales is done like cattle not pets. And you arrange that or hire someone who can (and as always scrutinise them, learn their job so you can question them).
Good luck!
Without external funding you will need to find a customer that will back you. What I mean is, an account that is large enough to pay for the three of you to continue to build out the platform + will expand + is a known logo you can use and will work with you for marketing purposes (case study, referrals/references, webinars, conferences, etc.).
The tricky part is finding the right "design partners" that can back you financially and help with marketing, while not totally derailing your roadmap. You need to make sure you continue to build for your total addressable market, not just your top paying customers.
How would you scale it if you had a $10 million check from a VC in hand?
If there are only 3 of you, why do you want to scale to $100m AAR?
I think more details would help. Like if ATM you apply any effort to get customers, or do you have churn and burn money to get new customers. If there is a churn — fix it.
Why don't you grow by word of mouth? Is there a space to grow?
Is it possible to change/update model and allow end users to use it?
You need to watch your CAC Payback Period very very very closely. This is the thing that kills otherwise successful SaaS companies... they are profitable long-term but bankrupt short-term, and end up needing to scrape up funding with terrible terms to bridge that gap.
All customers will cost you something on the front end, even if it's just time. That time is money. How long does it take to earn enough profit to pay that back? Higher margin and lower operation cost --> faster payback period --> ability to onboard customers faster.
Stated differently: if 10M new customers walked through your door tomorrow, could you onboard and retain them immediately? Probably not. Determine your new customer flow rate and gear your sales + advertising activities to hit that rate. Then you can add more business capacity and continue to scale.
One more thought: as you scale, how can you lower your employee cost? People talk about remote hiring, and that's an option, but there's also another shortcut: mission. People will take less money for the same work if they're excited about the mission. Mission IS compensation. What makes a good mission? Maybe you're focused on minority-owned small businesses. Maybe you're offering a chance for developers from non-traditional backgrounds to grow. Maybe you employ ex-cons. Maybe you're trying to launch a rocket to Mars. Whatever it is, find the GENUINE thing that makes your story super unique and use that to attract good employees for less cash.