Pick a depth. Each prompt opens in your AI pre-loaded with the lesson. Click a row to preview the prompt.
The architectural leap isn't cryptographic — it's that there is no api.ethereum.com. Every full node holds the entire ledger, re-executes every transaction, and enforces identical rules. You don't ask a server 'is this transaction valid' — you run the rules yourself, or trust one of thousands of peers who does.
At this moment there are roughly 8,000 Ethereum execution-layer full nodes and 1M+ validators running consensus clients, plus tens of thousands of Bitcoin nodes. None of them is authoritative. If you run geth/reth/erigon locally and sync, your laptop is as canonical as Vitalik's — same rules, same state root. Contrast this with api.stripe.com, where Stripe's DB is the only truth.
// main.go — query eth_blockNumber from two public RPCs and compare
// Run: go run main.go (stdlib only)
package main
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
"strconv"
)
func blockNumber(rpc string) (int64, error) {
body := []byte(`{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}`)
resp, err := http.Post(rpc, "application/json", bytes.NewReader(body))
if err != nil {
return 0, err
}
defer resp.Body.Close()
var out struct {
Result string `json:"result"`
}
if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
return 0, err
}
return strconv.ParseInt(out.Result[2:], 16, 64)
}
func main() {
for _, rpc := range []string{"https://cloudflare-eth.com", "https://eth.llamarpc.com"} {
n, err := blockNumber(rpc)
if err != nil {
fmt.Println(rpc, "-> error:", err)
continue
}
fmt.Println(rpc, "->", n)
}
}
go run main.go