# Ossification on ETHBEAT (formerly L2BEAT)

> How long the critical contracts of each tracked project have gone unchanged, and how much value they secured meanwhile, with the exit window where the project has one.

Ossification measures how battle-tested the code securing a project is: the share of recorded code-bug exploits ([published, onchain-verified dataset](https://github.com/l2beat/ossification-dataset)) whose exploited code was younger than the project's critical contracts are today. The clock starts at the ossification genesis, and every critical change resets it. Battle-tested exposure is the value they secured over the unchanged period, in USD-years.

Ossification is not calculated while any critical contract lacks verified source code. Critical changes per year count the trailing 36 months, or the time since the ossification genesis if shorter. The exit window is how long users have to leave before a permitted critical change takes effect; it does not affect ossification.

## Layer 2s (/layer2s/projects/{slug})

- [Celo](https://ethbeat.org/layer2s/projects/celo): ossification 73%, clock since 26 May 2026, battle-tested exposure $113.96 M·years of TVS, 8.1 critical changes / year across 24 contracts, exit window: None
- [Arbitrum One](https://ethbeat.org/layer2s/projects/arbitrum): ossification 59%, clock since 31 Aug 2026, battle-tested exposure $1.90 B·years of TVS, 5.3 critical changes / year across 52 contracts, exit window: None
- [Mantle](https://ethbeat.org/layer2s/projects/mantle): ossification 54%, clock since 17 Sep 2026, battle-tested exposure $183.62 M·years of TVS, 4.3 critical changes / year across 16 contracts, exit window: None
- [OP Mainnet](https://ethbeat.org/layer2s/projects/op-mainnet): ossification 52%, clock since 24 Sep 2026, battle-tested exposure $210.33 M·years of TVS, 7.0 critical changes / year across 23 contracts, exit window: None
- [Ink](https://ethbeat.org/layer2s/projects/ink): ossification 52%, clock since 24 Sep 2026, battle-tested exposure $43.74 M·years of TVS, 7.3 critical changes / year across 24 contracts, exit window: None
- [Morph](https://ethbeat.org/layer2s/projects/morph): ossification 52%, clock since 22 Sep 2026, battle-tested exposure $18.68 M·years of TVS, 12 critical changes / year across 18 contracts, exit window: None
- [Unichain](https://ethbeat.org/layer2s/projects/unichain): ossification 52%, clock since 24 Sep 2026, battle-tested exposure $9.95 M·years of TVS, 8.0 critical changes / year across 24 contracts, exit window: None
- [Scroll](https://ethbeat.org/layer2s/projects/scroll): ossification 52%, clock since 22 Sep 2026, battle-tested exposure $5.14 M·years of TVS, 9.0 critical changes / year across 56 contracts, exit window: None
- [Katana](https://ethbeat.org/layer2s/projects/katana): ossification 50%, clock since 30 Sep 2026, battle-tested exposure $5.01 M·years of TVS, 21 critical changes / year across 34 contracts, exit window: None
- [Base Chain](https://ethbeat.org/layer2s/projects/base): ossification 46%, clock since 7 Oct 2026, battle-tested exposure $1.15 B·years of TVS, 8.3 critical changes / year across 24 contracts, exit window: None
- [Linea](https://ethbeat.org/layer2s/projects/linea): ossification 46%, clock since 8 Oct 2026, battle-tested exposure $25.38 M·years of TVS, 9.3 critical changes / year across 18 contracts, exit window: None
- [Starknet](https://ethbeat.org/layer2s/projects/starknet): ossification 43%, clock since 14 Oct 2026, battle-tested exposure $25.24 M·years of TVS, 13 critical changes / year across 48 contracts, exit window: None
- [Aztec Network v6](https://ethbeat.org/layer2s/projects/aztecnetworkv6): ossification 33%, clock since 26 Oct 2026, battle-tested exposure $5.74·years of TVS, 0 critical changes / year across 13 contracts, exit window: ∞
- [Taiko Alethia](https://ethbeat.org/layer2s/projects/taiko): ossification 32%, clock since 27 Oct 2026, battle-tested exposure $233.96 K·years of TVS, 28 critical changes / year across 46 contracts, exit window: None
- [ZKsync Era](https://ethbeat.org/layer2s/projects/zksync-era): ossification 27%, clock since 30 Oct 2026, battle-tested exposure $3.13 M·years of TVS, 15 critical changes / year across 36 contracts, exit window: None
- [Lighter](https://ethbeat.org/layer2s/projects/lighter): ossification 22%, clock since 1 Nov 2026, battle-tested exposure $8.02 M·years of TVS, 34 critical changes / year across 5 contracts, exit window: None

## Privacy protocols (/privacy/projects/{slug})

- [Tornado Cash](https://ethbeat.org/privacy/projects/tornado-cash): ossification 98%, clock since 2 Apr 2021, battle-tested exposure $2.63 B·years of TVS, 0 critical changes / year across 21 contracts, exit window: Infinite
- [Privacy Pools v1](https://ethbeat.org/privacy/projects/privacy-pools): ossification 84%, clock since 22 May 2025, battle-tested exposure $6.35 M·years of TVS, 1.2 critical changes / year across 17 contracts, exit window: Infinite
- [Railgun](https://ethbeat.org/privacy/projects/railgun): ossification 61%, clock since 14 Aug 2026, battle-tested exposure $21.88 M·years of TVS, 0.7 critical changes / year across 8 contracts, exit window: 7d
- [zkAPI](https://ethbeat.org/privacy/projects/zkapi): ossification 50%, clock since 30 Sep 2026, battle-tested exposure $188.26·years of TVS, 0 critical changes / year across 3 contracts, exit window: None
- [zk.money](https://ethbeat.org/privacy/projects/zkmoneyv6): ossification 33%, clock since 26 Oct 2026, 0 critical changes / year across 16 contracts, exit window: Infinite

## DeFi protocols (/defi/projects/{slug})

- [Uniswap V2](https://ethbeat.org/defi/projects/uniswapv2): ossification 99%, clock since 4 May 2020, battle-tested exposure $13.23 B·years of TVL (source: DefiLlama), 0 critical changes / year across 3 contracts
- [Uniswap V3](https://ethbeat.org/defi/projects/uniswapv3): ossification 98%, clock since 4 May 2021, battle-tested exposure $12.27 B·years of TVL (source: DefiLlama), 0 critical changes / year across 4 contracts
- [Safe](https://ethbeat.org/defi/projects/safe): ossification 98%, clock since 25 May 2021, 0 critical changes / year across 12 contracts