> ## Documentation Index
> Fetch the complete documentation index at: https://docs.celo.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

Celo was launched in 2020 as a mobile-first Layer 1 blockchain designed to advance global financial inclusion through smartphone-accessible crypto payments and phone number-based addressing. Built on proof-of-stake consensus with a commitment to carbon neutrality, Celo's L1 featured fast, low-cost transactions and native stablecoins like cUSD that powered a vibrant DeFi ecosystem.

In 2024, Celo began migrating from its Layer 1 architecture to become an Ethereum Layer 2 network built on the OP-Stack. This migration aimed to achieve greater scalability and interoperability while preserving Celo's core mission and complete transaction history.
The migration was completed in March 2025 at block 31,056,500.

<Warning>
  This section documents the historical Celo Layer 1 blockchain before its completed migration to Layer 2 and does not reflect Celo's current L2 architecture.
</Warning>

### Technical Changes

The table below summarizes the technical changes involved in transitioning from Celo's Layer 1 to Layer 2:

| **Aspect**            | **Layer 1**                                                            | **Layer 2**                                                                                                |
| --------------------- | ---------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
| **Architecture**      | Single service, providing execution, consensus, and data availability. | Multiple services built on the op-stack with separate execution, data availability, and settlement layers. |
| **Bridging**          | Third-party bridges connecting to various chains.                      | Additional native bridge with Ethereum alongside existing third-party bridges.                             |
| **CELO Token**        | Lived on the Celo L1.                                                  | Lives on Ethereum; CELO on L2 represents CELO bridged from Ethereum.                                       |
| **Blocks**            | 5s long, 50M gas.                                                      | 1s long, 30M gas.                                                                                          |
| **Extra Fields**      | —                                                                      | Withdrawals & withdrawalsRoot, blobGasUsed & excessBlobGas, parentBeaconBlockRoot.                         |
| **Removed Fields**    | —                                                                      | Randomness, epochSnarkData.                                                                                |
| **Validator Duties**  | Operated the consensus protocol.                                       | Validators will temporarily operate community RPC nodes.                                                   |
| **Validator Rewards** | Distributed at epoch blocks.                                           | Distributed periodically via smart contract execution.                                                     |
| **Sequencing**        | Determined by the output of consensus, run by validators.              | Initially handled by a centralized sequencer with plans for decentralized sequencing later.                |
| **Precompiles**       | —                                                                      | All Celo precompiles removed except for the transfer precompile which supports token duality.              |
| **EIP1559**           | Governable implementation on-chain.                                    | Upgraded implementation with modified parameters across networks.                                          |
| **Hardforks**         | —                                                                      | Cel2 hardfork for transition to L2 alongside other op-stack hardforks.                                     |
| **Transactions**      | —                                                                      | Deprecated transactions include Type 0 with feeCurrency field and Type 124.                                |
| **Finality**          | One block finality, instantaneous once block is produced.              | Finality depends on trust in sequencer, batcher, proposer, and eigenDA, or ultimately on Ethereum.         |

For more detailed technical changes, see [Celo's L2 Migration Documentation](https://specs.celo.org/l2_migration.html).