Milestones
- Alpenglow whitepaper publishedMay 2025Complete.
- Validator vote (SIMD-0326) passesSep 2025Complete.
- Testnet deployment and client integrationTarget 2026Current milestone.
- Mainnet activationTarget Oct 2026Not yet reached.
Most important updates
- 15d ago
- 16d ago
- May 2026
- 2 Sep 2025
- 19 May 2025
Upcoming
- 2026Testnet deployment and client integration (next)
- Oct 2026Mainnet activation
Current obstacles
- Switching a live network's consensusEvery client must implement identical logic and cut over flawlessly, on a network holding billions.
- Lower fault toleranceIt tolerates 20% bad stake, below the usual one-third. A deliberate trade for speed that needs stake to stay spread out.
Physics limits
- Speed trades against fault toleranceClassic consensus survives up to one-third bad stake. Alpenglow's one-round fast path needs 80% of stake and tolerates 20% malicious plus 20% offline, a deliberate trade of safety margin for speed.
- Light across the planetSignals in fibre travel ~200,000 km/s, so crossing half the globe takes ~100 ms. With validators on every continent, 100–150 ms finality is already close to that physical floor.
- Leader upload bandwidthEach leader must upload its block, plus redundant coded pieces, within a ~400 ms slot. Its upload link caps how much data a block can carry, whatever the software does.
How it works
Votor
Two voting paths
Validators vote on each block. With 80% of stake in round one it's final. Otherwise a second round at 60% finalises it.
Rotor
One-hop data relay
The leader splits a block into slices sent to relays, which pass them to all validators in one hop. Less delay.
Certificates
Bundled vote certificates
Votes are bundled into certificates instead of being sent as transactions. Today votes make up most Solana transactions.
Spec sheet
| Spec | Alpenglow consensus | Tower BFT + Proof of History | Change |
|---|---|---|---|
| Target finality | ~150 msR (reported) | ~12.8 s | —no comparable change |
| Fast-path threshold | 80% stake, 1 roundR (reported) | — | —no comparable change |
| Slow-path threshold | 60% stake, 2 roundsR (reported) | — | —no comparable change |
| Fault tolerance | 20% byzantine + 20% offlineR (reported) | — | —no comparable change |
| Slot time | ~400 msR (reported) | — | —no comparable change |
R reported by the company
Papers & demos
- May 2025paperAlpenglow: A new consensus for Solana (opens anza.xyz)Specifies the new voting. Tolerates 20% bad plus 20% offline stake, with ~150 ms finality.
Update log
Fri 25 Sep
- Minor: PressTest
Thu 24 Sep
- Major: PressTest
May 2026
- Minor: PressTest
Tue 2 Sep 2025
- Major: PressSoftware
Mon 19 May 2025
- Major: BlogResearch
About Solana
Solana
Fast L1 blockchain, Firedancer, Alpenglow
Fast blockchain that runs many transactions in parallel on one shared ledger, with ~400 ms blocks. Maintained by Solana Labs, the Solana Foundation and client teams incl. Anza and Jump Crypto. A new voting system, Alpenglow, aims to cut finality from ~12.8 s to ~150 ms.
- Jump Crypto's Firedancer client went live in Dec 2025, so Solana no longer depends on one software client.
- Validators approved the Alpenglow rewrite in Sept 2025. It's expected to go live with client v4.3.
- Multi-hour outages in 2021-2022 and Feb 2024 drove investment in a second client and networking fixes.
- Founded
- 20188 yrs
- Headquarters
- United StatesSwitzerland
- Status
- Private
- Valuation
- private
- Works in
- CryptoBlockchains (L1s)
- Coverage
- 2 programs · 11 updateslatest 15d agochecked 25 Sep
- People
- Anatoly Yakovenko (opens en.wikipedia.org)Co-founder, Solana LabsRaj GokalCo-founder, Solana LabsLily LiuPresident, Solana Foundation