> I'd want to be able to define a model like "I think the fair value of a company is its net current assets plus its last 5 years of earnings", and have the tool email me whenever I can buy shares in any company substantially below that price, or sell them substantially above.

Be careful with investing using a model like this: you're basing the value of the company entirely on its historical performance and not at all looking at what its future may look like. It's a great way to end up in value traps.

Exaggerated example, you see Intel's stock price has taken a huge dive that puts it under your limit so you buy a bunch of the stock. But it turns out the reason Intel is now cheap is because ARM, AMD and NVidia have eaten its lunch, and its future looks incredibly shaky.

Likewise, selling stocks that are substantially above some past valuation is also a good way to exit from positions that are likely to continue to outperform. Stocks get "re-rated" by the market when their future prospects have improved. That's not a great time to exit the stock - if anything it's a time to buy more.

YMMV, value investing is still successful of course, but you do need to look forwards not backwards.

Hi the data is from https://site.financialmodelingprep.com/developer/docs

> Attribution is required for all users. It is as simple as putting “Data provided by Financial Modeling Prep” somewhere on your site or app and linking that text to https://financialmodelingprep.com/developer/docs/.

I don't see attribution on useequityval.com?

How much do you have to pay for data?

Thanks

You should checkout fintool.com, you can ask in natural language for this kind of data and soon set up alerts on it

Thanks for pointing that out - fintool seems really impressive as well

Getting the data is always the hard part for stock apps. My experience has been that it’s very difficult to get up to date data for free. You’ll probably have to pay for an API. You’ll probably want to anyway so that you aren’t juggling several free APIs to get the same data, or so you’re working with a mature, easy to use, RESTful API. I’ve worked with stock market APIs that are miserable to use.

This is exactly the kind of tool I would want as well. I was surprised nothing like this exists already.

Sounds like maybe i should build a notification system so if a stock drops a certain percentage below your models estimated value you get alerted?

Yes, at least that would be a great start for me.

I don't know if this is the reason but it is somewhat trivial to roll your own. This is actually close to the story of how I became a programmer in the first place. 17 years ago or so, I made something like this in Excel and figured out how to populate the data from the Yahoo! Finance API, then learned about FRED, BLS, other sources of possibly relevant economic data, but still doing everything in Excel, eventually deciding to learn C++ since I'd heard it was the industry standard for finance. I caught the bug, ended up being more into software than finance specifically, and the rest is history. My motivation at the time was this was the middle of the big global financial crisis, everything had tanked, and it seemed like a great time to get in low. Buying my first house in 2009 was probably the most advantageous thing I did, though I was at least able to do that by tax-free early liquidation of an IRA that was full of self-picked stocks.