What Solana is

Solana is a public blockchain: a shared ledger that anyone can read, write to and build on, run by roughly a thousand independent computers called validators around the world. Nobody owns it, nobody can freeze it for you, and it never closes.

What makes Solana different is speed and cost. A new block lands every 200 milliseconds, and a typical transaction costs around $0.00025. That changes what's practical. You can swap, lend, trade or pay onchain without fees eating your balance, which is why so much of crypto's trading and DeFi activity happens here.

How it works, in one minute

Time on Solana is split into short windows called slots. For each slot, one validator is scheduled to be the leader: it collects transactions, orders them and produces the block. Leaders rotate every few slots on a schedule everyone knows in advance, so transactions can be forwarded straight to the next leader instead of waiting in a global queue.

The other validators check each block and vote on it. Once enough stake has voted, the block is final. From October 21, 2026, a new consensus protocol called Alpenglow takes over and cuts the time to finality from about 12.8 seconds to roughly 150 milliseconds. There's a full lesson on it in the advanced track.

What SOL is for

SOL is Solana's native token. It does three jobs:

• Pays fees. The base fee is 5,000 lamports per signature (0.000005 SOL). Busy moments can add an optional priority fee so your transaction lands faster.
• Secures the network. Validators stake SOL as a guarantee of good behavior. You can delegate yours to a validator and earn a share of the rewards, around 5% a year right now.
• Keeps accounts alive. Every account holds a tiny refundable deposit called rent. You get it back when the account closes.

Why DeFi lives here

DeFi (decentralized finance) means financial apps that run as programs onchain: exchanges, lending markets, staking, derivatives. On a slow, expensive chain, a $50 swap can cost $5 in fees and wait minutes. On Solana it costs less than a cent and settles almost instantly, so small users can do what only whales could afford elsewhere.

Some numbers to anchor that, from DefiLlama: Solana DeFi holds about $5.9 billion in deposits, trades over $1 billion a day on DEXs, and carries more than $15 billion in stablecoins.

What it isn't

Fast doesn't mean safe by default. Solana apps can have bugs, tokens can be scams and there's no customer support to reverse a mistake. The rest of this academy is about using it well: setting up a wallet properly, understanding what you're signing and knowing the risks of each kind of app.