Show HN: I built an app store for open-source financial plans (on spreadsheets)

Hi HN, Mahmoud here. I'm usually here for Python/FOSS reasons (boltons, glom, CalVer, ZeroVer), and that's still the case, but this time with a twist.

While I was on parental leave from Stripe a couple years back, I started helping my parents figure out their retirement. They're academics coming from overseas, so let's just say I'm a big part of the plan. We found ourselves quibbling over Zoom screenshares, multi-tabbed Google Sheets, and countless links to articles and blog posts. When we looked for professional advice, we found conflicting guidance and misaligned incentives.

I looked at the tools my friends and I use for big decisions and saw a huge gap. This isn't budgeting, nor is this investing. This is actual finance. Money management and decision making. Your options are usually:

1. Read a bunch of Bogleheads, Investopedia, Wikipedia, and Reddit. Then cobble together spreadsheets that we can only hope someone wants to look at (including future you). 2. Hire an expert, which involves a lot of trust, time, and money. You can't shop around too much and you also can't turn back the clock if your advisor burns you. They'll do the spreadsheeting (hopefully correctly) and ignorance is bliss.

I wanted something different. I wanted consumer FP&A, if there were such a thing. A collaborative sandbox for sharing financial context, with a bit of math, plus discussion threads with a context-ful chatbot, and an "explorable explanation" that my parents could use to see how different choices applied directly to them. Google Sheets just wasn't it.

Most importantly it had to solve the trust issue. Most bespoke financial apps are black boxes. I wanted something transparent, verifiable, and forkable. Like open-source software. So, I built FinFam on top of the most broadly-understood low-code platform of all time: the spreadsheet.

FinFam (https://finfam.app) is a platform where you can build and share interactive financial models, powered by XLSX and Google Sheets.

A few examples of questions I've worked through with my early access users:

- https://finfam.app/mahmoud/views/child-cost - How much will it cost you to raise a child from 0 to preschool in the Bay Area?

- https://finfam.app/mahmoud/views/big-tech-vs-startup - Should you take a big tech job or join a startup?

- https://finfam.app/mahmoud/views/ccp-oas-age - When should you start taking your Canadian retirement benefits?

Building each of these models has been super rewarding. The child cost one in particular was a great way to capstone my daughter's 3rd birthday. Yes, I really do have a dataset of her first 2800 diaper changes: https://finfam.app/blog/2025-08-26-baby-cost-view-case-study

Not only has it been more fulfilling and maintainable for me, I'm hopeful that it can open up a new audience of "sheetcoders". There are tons of folks with domain knowledge and spreadsheet know-how, but would never learn (or even vibecode) js/html/react. This way they can build something interactive, without losing the narrative guidance of a good blog post. Get subscribers, find new clients, maybe even get some MRR.

We've been running private alpha all summer. It's still got rough edges, but our small community is getting too much value out of it not to share. Would love to hear what you think. Thanks!

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x1798DE a day ago | parent | next [-]

Wow this looks really well done, congratulations!

One question: I was exploring the public spaces and I'm wondering are these your real finances, or is this just a mocked-up example? https://finfam.app/mahmoud/space

And if they are your real finances, are you manually entering in things like your credit card balances, or do you have integrations that automatically track that? If there aren't integrations already, is that on the road map?

	▲	mhashemi a day ago \| parent [-]
		Haha, re: finances, everyone wants to know this! Give or take, yeah! I just felt obligated to go all in with the dogfooding. It's probably TMI for most folks, but other users don't have to do the same: https://finfam.app/faq#faq-data_visibility FinFam is private by default, but publishable by design. It's also totally valid to build/publish hypothetical/prototypical scenarios for the sake of demonstration. Re: manual entry, the income and expenses were, yeah. The balances from the accounts are all ingested via our "Magic Sync" which is really just parsing from screenshots. Works with Monarch Money, works with spreadsheets. And you don't have to deal with the nightmare of "open banking" (I helped build the first version of Stripe's Financial Connections product and I'd like to delay using it as long as possible...)

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ngtvspc a day ago | parent | prev | next [-]

Oddly my first impression was “wow this is sort of niche”, but then immediately realized how odd that sentiment is.

There are so many poor quality self help books out there on finance, that really amount to nothing more than a blog post. And whenever I’m trying to learn more or think about what options exist it feels like quite a slog. I’m definitely tired of pretty much all of the accessible financial advice amounting to using the standard 3 fund portfolio: https://www.bogleheads.org/wiki/Three-fund_portfolio

While it’s a fine starting point, it definitely bothered me how inaccessible financial advice is, even with an advisor it gets pretty hand wavey

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mhashemi a day ago | parent [-]

Haha, spent many hours on the Bogleheads wiki, and I do love it. But yeah, I'd love it even more if it had fields I could punch values into. If only there was some sort of site for that...

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ngtvspc a day ago | parent [-]

I wonder what that calculator would look like? Maybe something that lets you visualize trends of return for different fund blends?

That doesn’t seem particularly useful however, maybe something to help contrast the other common investment profiles? I just wouldn’t know which ones those are

	▲	mhashemi a day ago \| parent [-]
		I have a whole rant about this saved for a future blog post. The short version is that people need actionable belief. Charts are useful to demonstrate a concept, but at the end of the day, we want answers. I'm sure there's _someone_ you trust. Whether it's your dad or a friend or a podcast, I think the main gap is giving the user specific action. For example, https://finfam.app/heyfinfam/views/rent-vs-buy boils it down to Rent/Neutral/Buy. Most of the other featured views do the same, to eliminate the exact ambiguity you're describing.

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setheron a day ago | parent | prev | next [-]

I really like it; the community curations are neat. So many ideas to explore and I wonder if it can model pre-existing events like if I wanted to explore: Should I DCA ? (I can look historically)

	▲	mhashemi 21 hours ago \| parent [-]
		Hmm, DCA is one I think about a lot. Probably pretty easy to convert this research over: https://investor.vanguard.com/investor-resources-education/n... The result won't be super surprising, but it'll be more specific.

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arshanahmad a day ago | parent | prev | next [-]

Looks really cool. I’m going to try this. Are there plans for plaid integrations? Might want to partner up on something.

	▲	mhashemi a day ago \| parent [-]
		Thanks! Yeah, far-flung plans for integrations. Currently I'm getting way more mileage out of letting other products do the integrations for me. I.e., I use Monarch Money and just upload the screenshots to FinFam which parses out the balances. I helped build the first version of Stripe's Financial Connections product and while the alumni credit is tempting, I'd like to delay using it as long as possible... Too many error conditions and it's not like planning calls for that level of precision anyways.

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markrwilliams a day ago | parent | prev | next [-]

I'm an AI skeptic but the chatbot sounds interesting. What kind of context do you provide it?

	▲	mhashemi a day ago \| parent [-]
		Relatable. While I doubt I'd have been able to do all the frontend myself without an agent, it's still pretty early for LLMs + money. It depends on where you're starting a thread, but assuming you're starting the thread in a view, then we prime the chat with: - The user's configured financial literacy, education level, etc. - The reasoning and actual results of the calculator as you see them - Summary metrics from the space that the view is saved in The last point is pretty critical. The idea is that you build your own context from the bottom up, exposing as much or as little as you want for the scenario you want to explore. Add the relevant assets/liabilities/income/expenses, and we have a little cash-basis accounting simulator that projects all that into a "scope" usable by the Views, as well as the chatbot ("Finn" http://finfam.app/finn). Handing these metrics to the chat unlocks a lot of the magic of the chatbot as a "neutral explainer". Any creator can upload a spreadsheet, but as we've currently exposed it, Finn is meant to be moderate and just there to close any explanatory gaps that the creator may have left out, or not considered. If you're looking at a view about buying a second house, Finn's supposed to give you a gut check if you have particularly low cash reserves. A lot of a financial advisor's time and role is filling gaps in your financial literacy, and a 24/7 chatbot is honestly just better at explaining the difference between a credit and debit card.

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ltbarcly3 a day ago | parent | prev [-]

I've been waiting years for someone to make this. What are your plans to monetize?

	▲	mhashemi a day ago \| parent [-]
		Haha, glad you like it! So, originally this was a B2B concept for a friend who was starting an advisory. Original model was around referrals, and advisor client funnels. That might still have a place, but tbd. The B2C version you're looking at is an app store, so marketplace / app fee structure. Currently, when you save a View to your space, you're actually subscribing to updates. Instead of paying for a newsletter you have to read, digest, and model off, FinFam enables a paid subscription to a spreadsheet that gives you an answer. Skip the read, straight to the guidance. For most people facing decisions with significant financial components, they keep an eye on the situation for weeks if not months. If they're subscribed to an expert's View, they can pay per update or per time period, kind of like Patreon. I'm thinking we'll probably add some premium tier for certain SaaS features. E.g., similar to Figma, you can have X spaces, but if you want more, you need to pay more. Something tied to advanced use cases, # of chatbot convos, etc. For now it's all available for the low low cost of bug reports. the more detailed the better!