How to make a block explorer? I need to make a block explorer for some alternative cryptocurrencies. I'm using Litecoin for testing, but JSON-RPC requests through PHP are very slow. Maybe JSON-RPC isn't the right thing for such purposes? What other tools you can recommend?
Index the blockchain in a database and keep the database that has the blockchain updated as blocks come in, you would be essentially running a modified node that's really good at keeping data.