How to Check Balances for Multiple Bitcoin Addresses

I've seen a lot of people asking how to check balances for tons of bitcoin addresses. Like, if you've got a list of thousands, what's the trick?

Most likely, they wanna check a bunch of empty addresses. If you have a list in a.csv file, filtering through 10,000 addresses isn’t too bad. But imagine millions. Your computer might choke on that.

Businesses flip this around. They watch their mempool for new transactions and check against a small list of outputs they care about. They don't get swamped, so it's way easier for them.

But what if their system goes down? And what about those edge cases? The script OP is sharing could actually help businesses confirm their coin holdings too, you know.

Why not just wait and grab the whole file from Blockchair? No need to spam servers with requests. Seems like a better approach.

Didn’t know that file had a download limit. Thanks for the heads up!

I think that’s what OP was getting at. If you're checking millions of addresses, public explorers will slap you with rate limits.

True, but there’s still the ethical side of using someone else's explorer without permission. It’s a sketchy area.

Last comment from me on that, before it goes off the rails.

Why not just get an API key from blockchain.com? I got one, and it gives balances with transaction counts.

If anyone wants a copy without limits, I've linked the latest version here.

Can someone tweak the code to get public addresses too?

I meant public keys, can you modify your code?

I've tried a super quick method before: get funded addresses, make a list of the ones you want, merge, sort, and check for duplicates. Easy on Linux with just a few commands!

Yeah, that’s cool if you’re just after current balances. I’m more interested in history like, has this address even showed up before?

I ran a test on my old laptop: checking 300k addresses against 30 million took just 6 seconds. Blockchair's slow though, and Bitcoin Core could be a better bet.

Yup, syncing Bitcoin Core and parsing blocks is a mission. Not easy at all. Which parser are you using now? I updated my address list a while back, but it was a slog.

I started with a different approach, but splitting tasks helps manage CPU load. I can set up a mirror for those files with better speeds if anyone wants.

I’d like to know your method too, but the SHODAN part sounds tricky.

First step is finding exposed Insight servers online. Search Shodan for "port:3001 insight bitcoin". I registered but can’t seem to figure out the right command.