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This guide serves as a starting point for Exchanges and RPC Providers to understand F3 and leverage the new V2 APIs for faster finality confirmations.

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Status

• 2025-06-26: Feedback was incorporated from implementers. It’s now ready to receive feedback from the wider ecosystem.
• 2025-06-05: This document was created to help exchanges and RPC providers understand F3 and the new V2 APIs. It is currently a DRAFT.
• 2025-04-29: F3 was activated on Mainnet.

🌟 Introduction

This guide provides essential information for Exchanges and RPC Providers about F3 (Fast Finality) in the Filecoin network and how to leverage the new Lotus V2 APIs.

In this guide, we will:

1. Define 💭 What is F3 (Fast Finality)? and its purpose.
2. Explain 🏢 Benefits
3. Provide ⚙️ Practical Implementation Guide for V2 APIs
4. Answer ❓ Frequently Asked Questions

💭 What is F3 (Fast Finality)?

F3 is a consensus mechanism in the Filecoin network that dramatically reduces transaction finalization times, providing significant benefits for exchanges and RPC providers.

🏁 F3 reduces finality time from 7.5 hours (900 epochs) to just a couple of minutes. This transformation enables much faster deposit confirmations and withdrawal processing, dramatically improving user experience as users no longer need to wait hours for transaction certainty.

🤝 It works alongside the existing Expected Consensus (EC) mechanism. F3 provides fast finality when operating normally, but if F3 encounters issues, the system automatically falls back to EC finality. This hybrid approach ensures robust operation without compromising network reliability.

🎬 It provides deterministic finality, improving upon EC's probabilistic finality. Once F3 finalizes a transaction, it cannot be reverted, giving much stronger guarantees for financial operations that exchanges and RPC providers depend on.