Adios, Expiry: Rethinking Liveness and Liquidity in Arkade
Introducing trust-minimized delegation and the Intent coordination framework
Arkade's batch expiry mechanism serves an important role in liquidity management. Periodic renewal of VTXOs allow for efficient allocation of resources across the system. Active users pay fees proportional to the time value of money.
In Ark-based protocols, Operators provide the funds needed for commitment transactions and expiry ensures this capital doesn't remain indefinitely tied up into inactive VTXOs. When VTXOs expire, they are swept by the operator who is able to redeploy the liquidity to serve new ongoing demand. It's a market-driven approach that keeps the system economically sustainable and optimizes the pricing of liquidity.
However, expiry requires users to periodically renew their VTXOs to maintain unilateral exit rights, introducing liveness requirements for users. Missing a renewal cycle means expired VTXOs are swept by the operator, and while users can recover their funds, they lose the ability to unilaterally enforce ownership claims onchain.
For Bitcoin users used to "set it and forget it" self-custody, this feels like a step backwards. While the actual risk is often overstated, this active management responsibility is an important consideration for developers and users evaluating Arkade.
Current solutions require platform-specific strategies, some more reliable than others. Browsers sometimes restrict background execution environment available to native applications. Service workers provide new approaches to background processing, but remain constrained by user permissions and browser security models. On mobile, silent push notifications can wake applications for background renewal and maintain persistent background execution contexts.
Servers offer the most flexibility with cron jobs and scheduled tasks. Our dedicated Lightning application, Fulmine, supports automated lifecycle management of VTXOs for backend deployments.
Building on this foundation, we've developed a fundamentally different approach that opens up an entirely new design space for managing VTXO lifecycles.
Today, we're introducing this new framework along with a brand new primitive for VTXO management.
Delegation: Abstracting Expiry Management
Delegation allows users to authorize a third party to renew their VTXOs on their behalf, enabling seamless renewal and alleviating concerns about missed expiry windows. Users retain full unilateral control of their funds in the process. By leveraging delegation, application developers can completely abstract away batch expiry management, creating familiar user experiences identical to existing self-custodial applications.
The key breakthrough is enabling a fluid and modular trust model. Users can move from full unilateral control to practical delegation fallbacks that are easily managed using lightweight infrastructure. Everything is achieved through application-level logic and smart client behavior without requiring any changes to the protocol. Just as Arkade already enables users to choose between preconfirmed speed and Bitcoin finality based on their needs, delegation extends this mechanism to the VTXO lifecycle.
Delegation also creates natural economic alignment where delegates earn fees for reliable service, incentivizing high-fidelity infrastructure and enabling a range of trust models from “Uncle Jims” to professional service providers.
Users can configure multiple delegates or mix delegation with manual renewals, ensuring graceful fallback if any delegate fails. Delegation transforms renewal from an active, interactive process requiring real-time coordination to a more streamlined provisioning process for each cycle. Users simply provide their delegate with the next intent and forfeit transaction which he then uses to handle all renewal coordination automatically.
This enables application developers, businesses, and financial services to offer delegation services as part of their existing Bitcoin infrastructure, creating competitive markets around reliability, fees, and service quality.
Users can also maintain full sovereignty by running their own delegate infrastructure, choosing their preferred level of self-hosting versus convenience.
How It Works
This capability is powered by a new coordination primitive we call Arkade Intents. These are Bitcoin-native ownership proofs that enable elaborate multi-party coordination without custody transfer. Intents were introduced in our recently released v0.7.0, marking a significant advancement in Arkade's coordination capabilities.
The Intent System
Arkade Intents use BIP322, the standardized Bitcoin message signing protocol, to create ownership proofs that register inputs for inclusion in the next commitment transaction. When you want to participate in a batch settlement, you create an Intent that proves ownership of your inputs (VTXOs, UTXOs, or other assets) and specifies what outputs you want to receive. By streamlining this process into Bitcoin’s transaction format, we can validate ownership of a script using the same logic as spending Bitcoin - each input simply requires a valid witness stack. Here's the basic flow:
1. VTXO Setup When you create a VTXO with delegation capability, it includes multiple spending paths:
- A+S (You + Server): Normal spending
- A+CSV(exit): Your unilateral exit after relative timelock
- A+B+S (You + Delegate + Server): Delegation path requiring all three parties
2. Intent Pre-Authorization You create and sign an Intent message specifying exactly what you want to happen (simplified example):
You sign this Intent using your A+S path, proving ownership and defining exactly what VTXOs to forfeit and what new VTXOs to create. You also provide a forfeit transaction signed with the A+B+S delegation path using SIGHASH_ALL|ANYONECANPAY.
This special signature type allows your delegate to add the connector input later without letting anyone modify the outputs you specified. You set the forfeit output amount to cover both your VTXO amount plus the connector amount. Your delegate receives your completed Intent and partial forfeit transaction - they cannot modify either, only submit them at the authorized time.
3. Coordinated Execution When renewal time arrives, your delegate submits your pre-signed Intent to the Arkade operator and joins the batch on your behalf. The operator validates the timing, ownership proof, and output specifications from your Intent. Your delegate receives a connector input from the operator, adds it to your forfeit transaction, and signs it with SIGHASH_ALL before submitting to the server.
Your delegate also participates in tree signing by providing a public key for the batch coordination. Everything settles atomically: your old VTXO is consumed, your new VTXO is created exactly as you specified in your Intent, your delegate earns their fee, and the operator coordinates the entire batch process.
Pre-committed outcomes. Your Intent cryptographically commits to exactly what outputs will be created, and your payment to the delegate is encoded directly in the Intent outputs. Your delegate can only control when you receive your renewal, not what you receive.
Timing constraints prevent abuse. Your Intent signatures include strict time windows. Delegates can only act during these authorized periods, and stale Intents are automatically rejected.
You never lose control. Every delegation action requires your signature, provided in advance through the Intent system. Delegates never have custody of your funds. If anything goes wrong, you retain full unilateral exit capability through your personal exit path.
Clear trust boundaries. You trust that your delegate will act reliably and that the operator won't collude to change outputs, but you don't need to trust them with custody or beyond their specific execution role. If your delegate fails to act, you can always exit unilaterally.
Beyond Delegation
While delegation addresses the immediate expiry challenge, Intents unlock broader possibilities for Bitcoin-native coordination.
Intents lay the foundation for long-living offchain contracts such as escrows, time-locked payments, and peer-to-peer loans. Traditionally, these contracts would expire and force participants to either settle onchain or start over. Using Intents, the same contracts can be seamlessly renewed and continue operating across multiple batches. This means complex financial agreements can persist and evolve entirely offchain, maintaining their original terms and conditions without needing to create new onchain transactions.
We'll be sharing technical deep-dives on these advanced applications in the future. Delegation represents the essential first step, demonstrating that sophisticated coordination and advanced signing policies can reliably provide robust user experiences on Arkade.
Technical Resources: