Bertly
personal finance tool with client-side E2EE
In April I started building Bertly.
For years I had helped friends and family manage money with spreadsheets. I wanted something as powerful as Excel, but without the friction.
From day one I wanted three things:
End-to-end encryption, so privacy is real, not a marketing line
Open source eventually, so the product can be transparent and auditable
Flexible enough to grow with someone’s life stages
That last point forced a design choice: data needs clear ownership.
If you live alone, you work in your own space. If you join a couple, that personal space stays yours. Summaries can feed a shared view so you can answer bigger questions together: How are we doing? Are we saving enough? Is our net worth strong enough?
Once I had a prototype, I ran a private beta with people close to me (family, friends, coworkers). About 20 people said yes. After three months, one still uses it every day. The other 19 signed up and stopped.
That was hard, and useful.
I opened a public beta recently because the next level of the product needs people who actually want to use it. Asking friends to “join the movement” does not scale. I need visibility and organic adopters.
So I started posting on X and Bluesky. Two things became obvious fast:
With almost no followers, posts go nowhere
Personal finance apps are a crowded category, and people still do not adopt most of them
My conclusion: trust comes before growth.
I am going to build that trust with content (YouTube, maybe podcasts). Not the usual “spend less than you earn” advice. I want to connect science and money: how stress, emotions, and financial context can narrow attention and change the decisions people make.
If you have been through a similar phase (private beta → almost nobody sticks → public beta with zero distribution), what advice should I keep in mind?
Site: https://www.bertly.app
In April I started building Bertly.
For years I had helped friends and family manage money with spreadsheets. I wanted something as powerful as Excel, but without the friction.
From day one I wanted three things:
End-to-end encryption, so privacy is real, not a marketing line
Open source eventually, so the product can be transparent and auditable
Flexible enough to grow with someone’s life stages
That last point forced a design choice: data needs clear ownership.
If you live alone, you work in your own space. If you join a couple, that personal space stays yours. Summaries can feed a shared view so you can answer bigger questions together: How are we doing? Are we saving enough? Is our net worth strong enough?
Once I had a prototype, I ran a private beta with people close to me (family, friends, coworkers). About 20 people said yes. After three months, one still uses it every day. The other 19 signed up and stopped.
That was hard, and useful.
I opened a public beta recently because the next level of the product needs people who actually want to use it. Asking friends to “join the movement” does not scale. I need visibility and organic adopters.
So I started posting on X and Bluesky. Two things became obvious fast:
With almost no followers, posts go nowhere
Personal finance apps are a crowded category, and people still do not adopt most of them
My conclusion: trust comes before growth.
I am going to build that trust with content (YouTube, maybe podcasts). Not the usual “spend less than you earn” advice. I want to connect science and money: how stress, emotions, and financial context can narrow attention and change the decisions people make.
If you have been through a similar phase (private beta → almost nobody sticks → public beta with zero distribution), what advice should I keep in mind?
Site: https://www.bertly.app
Bertly is a personal finance tool with client-side E2EE (EU-hosted). You enter your own data, with no third-party connections.
It is not perfect. I am happy with how far it has come, and I know there is a lot to improve. This phase is about making the experience clearer for real users, not about selling a finished story.
If you try it, I would love to hear what is missing or what you would improve. It is currently available on the web, and you can install it as a PWA on your phone.
You con also follow along X or Bluesky .
-
1
Nice launch. Curious, what's in your roadmap? Do you have long-term vision for integrating agentic tech into Bertly?
-
1
Thanks.
My priority right now is making the product simpler and reducing friction. Medium term I’d like Bertly on Google Play and the App Store, but that isn’t the focus yet. The web app and PWA already work across platforms.
Given that Bertly is E2EE and user privacy is central, I don’t see connecting external agentic AI in the future. What I could imagine later is local, on-device AI next to the client , helping people make better decisions with their full financial context still on their side. That path interests me, but it’s still a long way off. First I need a clearer, more useful product for real users.
-
Bertly is still in private beta, but I wanted something useful without asking people to create an account first. So I put three free calculators on the site:
Mortgage prepayment — if you have spare cash, compare lowering the monthly payment vs shortening the term:
https://www.bertly.app/tools/mortgage-prepayment-calculatorDebt payoff —find a repayment plan that fits your actual cash flow:
https://www.bertly.app/tools/debt-payoff-calculatorFX / investment gain — estimate the result of a trade in your base currency, using ECB reference rates for the buy and sell dates:
https://www.bertly.app/tools/fx-investment-gain-calculator
All of them: https://www.bertly.app/tools
No account required, and we do not store your data.
Hi Indie Hackers,
I'm Gerard. I stopped waiting for the next job offer and started building Bertly full time (https://www.bertly.app). This is the honest version of how I got here.
I have always liked finance
Not in a Wall Street sense. In a "I find this interesting and most people around me don't talk about it" sense. Money is still a private topic in many European families, which means a lot of quiet confusion.
My family was no different. At some point I started helping them design Excel sheets to log income and expenses so they could see their full financial picture more clearly. That turned into conversations about mortgage prepayment, using tax benefits where they applied, and thinking through investment options that matched their situation. Nothing exotic. Just the kind of clarity most people don't get because nobody sat down with them.
I liked doing that. It felt useful.
The science path
I'm a scientist by vocation. After finishing my PhD I moved to Sweden for a postdoc at Karolinska Institutet. Two good years. Then I went to the University of Michigan for about a year to finish the project I was working on, while my partner stayed in Stockholm.
After Michigan: a void I haven't fully resolved.
Academia is strange. It's not just about proving you are good enough to keep doing research. There are bureaucratic barriers, national rules around hiring, and a practical wall where being around three years past your PhD makes you harder to slot into standard positions.
Industry felt like a different world. Without contacts, CVs often never get past HR. I sent a lot of applications. Most went nowhere.
During the PhD years my partner and I lived carefully. That probably sharpened my attention to where money actually goes.
What I built instead
At some point I stopped waiting for a door to open and started building something I had been thinking about for a while.
Most finance apps want bank login or account sync. That is convenient, until you think about what it means for your data. For many people that trade-off is fine. For me, and I think for a meaningful group of people who care about this, it isn't.
Bertly is an end-to-end encrypted space to monitor personal finances and net worth. You enter what matters. Sensitive amounts are encrypted on your device before they reach the server, so I cannot read your numbers as the administrator. No bank login. Data is hosted in the EU.
I also think manual entry has a power that full automation does not. When you type what you spent or earned, you notice it. With bank sync, the numbers appear, but it is easier to stop paying attention. A bit of friction can be useful, as long as the rest of the product stays light.
There is also a shared household view: you can follow joint finances together without handing over every personal transaction.
Right now Bertly is in a private beta. Soon I will open a public beta so anyone who wants to try it can. I am trying to keep friction as low as possible: privacy by design, without making the product feel heavy. If it goes well, I would like to monetise it afterwards.
Where I am now
Building full time, still figuring out what sustainable looks like. The science career door isn't fully closed in my mind, but I've stopped waiting for it.
I built Bertly because I find personal finance interesting and because privacy in this space matters to me more than convenience. Whether that is a big enough market, I don't know yet.
A question for the community
How many of you track your personal finances carefully? If you do, do you use a tool, a spreadsheet, or nothing structured at all? I'm trying to understand who finds this kind of setup worth the effort of entering data manually.
Happy to talk if anyone is building in fintech or has thoughts on privacy versus convenience.
-
2
The “manual by design” choice is interesting, especially the point about a little friction making you actually notice where the money goes. The shared household view without exposing every personal transaction is a nice detail too.
This feels like it could be getting a lot more organic traffic than it probably is right now, especially while you’re still validating whether privacy-first finance is a big enough market.
Have you noticed which part of that privacy angle gets people most curious?
-
1
Thanks. That is a useful question.
In Europe I do notice more baseline awareness around personal data. You can feel it in how many privacy-first alternatives to big tech have taken root here: Proton, Tuta, Plausible. The appetite is real.
But most people in my closer circle (family, friends, coworkers) are not technical. They do not ask for end-to-end encryption by name. What they do care about is something more practical: not sharing financial data with third parties, and a general unease around anything money-related going anywhere they do not control. There is real fear there.
When I first described Bertly, a common reaction was suspicion. They assumed it meant connecting directly to their bank. After I explained how it actually works, a few agreed to try it and give feedback. The interface improved from those early conversations, though commitment stayed low. For a while I was mostly fixing what I already knew needed fixing.
In the US, tools like Monarch and YNAB show that this category can work. In Europe I have not seen anything with a similar presence. I still do not know whether that is because nobody has positioned it well, or because the demand is simply smaller here.
There does seem to be a boom of similar apps from indie developers right now. Many of them are Android or iOS first, and they feel built for momentum. Their websites are often quite superficial: you do not really understand what they offer until you download the app. I am trying to do the opposite: make the product understandable on the web first, including free tools people can use without signing up.
More recently I have been trying to communicate the product more clearly through the website. Bertly runs on web and mobile as a PWA, and I want to expand to Google Play and the App Store soon.
The real constraint right now is traffic. Getting people to actually try it, and in the best case building a small community I can eventually live from: that is where the work is. The conviction and the skin in the game are there. Distribution is the hard part.
-
1
I think there are two things to solve first: getting the right users to discover and try Bertly, and then building enough trust for them to feel comfortable using it for their finances.
I have ideas around both sides and would be happy to share what I’m thinking. If you want to go into the details, feel free to email me at mumar@growwithmumar.online.
-
-
-
1
The privacy-first angle is clear, but the manual-entry tradeoff is the more interesting part. I’d be curious whether users actually find that friction useful enough to stick with it over time.
-
1
Thanks. That is the question I am trying to answer honestly.
I am trying to combine both sides. You still open the app and enter what you spent or earned, so you notice it. At the same time I want to remove busywork: for example, remembering which category and subcategory you usually use for a merchant and prefilling that.
In my closer circle, people liked the awareness idea, but commitment stayed low. So I do not assume the friction is automatically useful enough. Public beta should tell me more than private feedback from people who already know me.
-
1
That’s a useful signal already — especially the gap between liking the idea and actually sticking with it. I’d be interested in hearing what you learn from the public beta. If you’re open it, what’s the best email to reach you at?
-
1
There’s still a lot to improve and polish, but I’m proud of what’s built so far. If you’d rather try the private beta now, email (hello @ bertly . app) from the address you want on the account and I’ll send an invite.
If you’d rather wait for the public beta, I’ll post about it here on Indie Hackers too — or I can email you when it’s live if you prefer (same address is fine).
-
1
Thanks — I’ll reach out there. I’d definitely be interested to see how the public beta plays out.
-
-
-
-
Comment