Spark Program | CKB-Sweep: Sponsored Cell Consolidation Utility

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The Challenge: State Bloat and Network Sustainability

In the CKB ecosystem, every “Cell” occupies a permanent footprint on the Layer 1 state. As the network matures, it faces a structural challenge: State Bloat. Thousands of fragmented, low-value UTXOs (Cells) remain dormant, increasing the hardware requirements for nodes and complicating transaction validation.

Currently, users lack a direct incentive to consolidate these “dust” cells because transaction fees often approach or exceed the value of the small Cells themselves. CKB-Sweep addresses this by removing the cost barrier entirely.

Applicant: Babar

Babar is a Senior Blockchain Engineer and Full-Stack Developer with extensive hands-on experience in Web3 development and modern web technologies. He has worked on a variety of projects including blockchain traceability, IoT device management, DeFi banking applications, PancakeSwap V2 clones, and tooling.

He possesses a broad technical skill set covering both backend and frontend frameworks. Babar specializes in decentralized systems — including staking, NFTs, and DeFi.

GitHub: babarhanif96

Technical Architecture: The Sponsor-Pay Model

By leveraging CKB’s flexible Cell Model, a third-party fee-payer subsidizes the transaction cost on behalf of the user. The transaction structure is as follows:

INPUTS

├─ User UTXO 1: 0.5 CKB (user signs)

├─ User UTXO 2: 0.5 CKB (user signs)

├─ User UTXO 3: 0.5 CKB (user signs)

├─ User UTXO 4: 0.5 CKB (user signs)

└─ Sponsor UTXO: 0.0015 CKB (sponsor signs — covers fee)

OUTPUTS

├─ Consolidated User UTXO: 2.0 CKB → user’s address

├─ Sponsor Change UTXO: 0.0005 CKB → sponsor’s address

└─ Network Fee: 0.001 CKB (deducted from sponsor input)

Key Logic: The transaction validates that the user’s total output CKB is identical to their total input CKB, without reducing the user’s balance. The fee is borne entirely by the sponsor.

Step-by-Step User Journey

  1. Network Scan: User connects via JoyID; the service identifies Cells meeting consolidation criteria (value below 100 CKB, dormant for 30+ days, or fragmented sets of 5 or more).

  2. Transaction Assembly: The backend creates a partially signed transaction, appending a grant-funded sponsor Cell to cover all fees.

  3. Authorization: The user signs only their specific inputs and never interacts with or has access to sponsor funds.

  4. Co-Signing & Broadcast: The service co-signs for the fee-covering input and broadcasts the complete transaction to the CKB network.

  5. Settlement: The user receives a single optimized Cell and the network state is reduced instantly.

Expected Deliverables

1. Open Source Codebase

  • CKB Scripts: Optimized Rust scripts for secure, multi-input Cell consolidation.

  • Backend Service: Node.js/Rust service for transaction assembly, sponsor pool management, and wallet connection.

  • Smart Contracts: Scripts handling the sponsor-subsidized transaction model.

2. Web Application (Live Demo)

  • Public Interface: A clean, accessible web UI for the full workflow.

  • Wallet Integration: Seamless JoyID support.

  • Preview Flow: Visual transaction breakdown and signing interface.

3. Documentation & Verification

  • Technical Docs: Developer guides for the consolidation script and API.

  • Final Demo: A video presentation showcasing the end-to-end user journey and metrics proving state reduction (before/after Cell counts).

Execution Roadmap & Budget

Total Funding: $1,800 (4-Week Timeline)

Week 1 – Core Logic ($700)

Multi-input script and sponsor co-signing mechanism.

Week 2 – Backend MVP ($700)

Transaction assembly logic and sponsor pool management.

Week 3 – Frontend/UX ($250)

Web interface, JoyID integration, and end-to-end testing.

Week 4 – Launch ($150)

Security review, documentation, and mainnet deployment.

Week 4 breakdown: $100 Sponsor Pool (for initial consolidations) + $50 Infrastructure.

Impact on the CKB Ecosystem

  • Node Sustainability: Lowering the total Cell count reduces long-term resource requirements for full-node operators.

  • Public Good Template: Provides a replicable model for gasless interactions on CKB, allowing other projects to sponsor user transactions.

  • State Rent Optimization: Aligns user behavior with CKB’s long-term scalability and decentralization goals.

Project Deliverables Checklist

  • Finalize CKB script for multi-input consolidation with sponsor co-signing

  • Implement sponsor pool management system

  • Develop transaction assembly logic (partial signing)

  • Integrate JoyID wallet support

  • Build frontend for Cell scanning and selection

  • Create developer documentation

  • Conduct security review of multi-sig transaction flow

  • Deploy MVP to CKB Testnet

  • Launch production service on CKB Mainnet

  • Publish all code as open source on GitHub

CKB-Sweep transforms a technical necessity state management into a friction-free utility. By leveraging the power of the Cell Model, we provide a zero-cost path for users to contribute to the health of the Nervos network while maintaining a cleaner, more efficient wallet.

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CKB Ecosystem Biweekly Update
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Hi Babarfi, I’m not saying that there isn’t a place for something along these lines, but I’m not sure you are understanding the way CKB works.

The minimum size of a Cell is 61 CKB and an average transaction fee is something like 0.0001 CKB, so there isn’t any CKB ‘dust’ in the same way that Bitcoin has dust UTXOs that are below the transaction fee cost.

But maybe there is still a reason that your project can be useful, I’m not sure if just cleaning heaps of UTXOs into a single UTXO is beneficial or not, but if it is, then an easy way for holders to do this might be good.

Also, who are the Sponsors and what do they get out of this? It looks like they just pay the fee and don’t receive any incentive.

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@Yeti Thank you for the sharp feedback — you’re right,. the dust framing doesn’t translate from Bitcoin to CKB and I should have framed this differently.

The real problem isn’t unspendable cells — it’s fragmented cells silently costing holders yield. Here’s the actual math:

Every cell must hold a minimum of 61 CKB just to exist on-chain — that’s not metadata overhead, it’s the minimum capacity a cell needs to justify its own existence in the UTXO set. If a user accumulates 20 cells from regular transactions, 20 × 61 CKB = 1,220 CKB is tied up just keeping those cells alive. Consolidating into a single cell means only 61 CKB is needed, freeing up 1,159 CKB that can immediately go into the Nervos DAO to earn yield. For a heavy user with 100 cells, that’s over 6,000 CKB freed.

So CKB-Sweep is less a ‘dust cleaner’ and more a yield optimizer — it turns the CKB trapped in redundant minimum-size containers back into Free Capacity.

On your sponsor question: in the context of this grant, the ecosystem fund itself acts as the initial sponsor pool. The fee per consolidation is so small (0.0001 CKB) that the grant covers a large number of transactions. Long term, wallet providers like JoyID have a natural incentive to co-sponsor this as a ‘One-Click Wallet Optimizer’ feature — it’s a direct value-add for their users and keeps wallets clean.

Happy to hear any further thoughts.

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i’m wondering how the user created these cells. If it is dust in a wallet (Neuron for example), the wallet takes care of calculating a balance of all the dust cells (and thus could perform the function you’re imagining in accumulating the cells and depositing into the DAO). I believe JoyID uses a single address, so it wouldn’t be subject to this issue.

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Hi @Babar, thanks for the proposal. However, after reviewing the technical details, there are several fundamental issues that need to be addressed before we can move this forward.

您好 Babar，感谢提交提案。但在审阅技术细节后，我发现了一些根本性的问题需要先行解决。

1. Core premise needs re-examination / 核心前提需要重新审视

This is the most important point. On CKB, users can already consolidate multiple Cells into one simply by sending a transaction to themselves — no special script or third-party tool is required. This is a native capability of the Cell Model’s UTXO-like architecture.

The proposal states that “users lack a direct incentive to consolidate these ‘dust’ cells because transaction fees often approach or exceed the value of the small Cells themselves.” However, the only barrier here is the transaction fee, not the lack of a consolidation mechanism. CKB transaction fees are extremely low (typically ~0.001 CKB), so the cost of a self-transfer consolidation is negligible in most cases.

This means the project as currently scoped — including custom Rust CKB scripts, a dedicated backend service, and a full web application — may be significantly over-engineered for a problem that largely has a built-in solution.

这是最重要的一点。在 CKB 上，用户已经可以通过给自己转账的方式将多个 Cell 合并为一个——不需要任何特殊脚本或第三方工具。这是 Cell Model 类 UTXO 架构的原生能力。

提案称"用户缺乏合并这些’灰尘’ Cell 的直接激励，因为交易费用往往接近甚至超过小 Cell 本身的价值"。但这里唯一的障碍是交易手续费，而非缺少合并机制。CKB 的交易手续费极低（通常约 0.001 CKB），因此在大多数情况下，自转账合并的成本可以忽略不计。

这意味着目前提案所规划的范围——包括自定义 Rust CKB 脚本、专用后端服务和完整 Web 应用——相对于一个已有内建解决方案的问题，可能严重过度工程化。

2. Technical inaccuracies / 技术细节错误

The example transaction shows Cells with 0.5 CKB and a sponsor UTXO of 0.0015 CKB. On CKB, every Cell must hold a minimum capacity of ~61 CKB (to cover the basic data structure: capacity field + lock script hash). Cells below this minimum cannot exist on-chain.

This means:

  • The example is not technically feasible as written.
  • The consolidation criteria (“value below 100 CKB”) would only apply to a very narrow range (~61–100 CKB).
  • The sponsor Cell itself (0.0015 CKB) also cannot exist.

These errors suggest insufficient familiarity with CKB’s Cell Model fundamentals. All technical examples that the proposal depends on must use real parameters.

示例交易中使用了 0.5 CKB 的 Cell 和 0.0015 CKB 的 Sponsor UTXO。但在 CKB 上，每个 Cell 必须持有至少约 61 CKB 的容量，低于此值的 Cell 无法在链上存在。

这意味着：

  • 示例在技术上不可行。
  • 合并条件（“价值低于 100 CKB”）的实际适用范围极窄（约 61–100 CKB）。
  • Sponsor Cell 本身（0.0015 CKB）同样无法存在。

这些错误表明对 CKB Cell Model 基础机制的了解不够充分。提案依赖的所有技术示例必须使用真实的参数。

3. Missing required fields / 缺少必填项

  • Bilingual version: Please provide a corresponding Chinese version of the full proposal. / 请提供完整的中文版提案。
  • Payment preference: The program allows 100% CKB or 100% USDI. Please state your preference. / 请注明支付方式偏好（100% CKB 或 100% USDI）。

4. Web5 alignment / Web5 契合度

The proposal does not reference any Web5 principles (DID, Decentralized Web Nodes, Verifiable Credentials, user data ownership, etc.). Please briefly explain how CKB-Sweep’s design or goals align with Web5 concepts mentioned in the Spark Program guidelines.

提案未涉及任何 Web5 原则（DID、去中心化 Web 节点、可验证凭证、用户数据自主权等）。请简要说明 CKB-Sweep 如何契合星火计划提到的 Web5 概念。

Thank you for joining CKB’s ecosystem development through the Spark Program

感谢你愿意通过星火计划加入到CKB的生态建设中

Looking forward to your response.

期待您的回复。

Best regards,
xingtian

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