Proposer: Subscan
Beneficiary: 14RYaXRSqb9rPqMaAVp1UZW2czQ6dMNGMbvukwfifi6m8ZgZ
Requested Funding: $249,250 USD
Category: Infrastructure

Past proposals:

• #151 Subscan | Infrastructure Costs of Subscan for Polkadot & Westend & Rococo Networks
• #20 Subscan | Infrastructure Costs of Subscan for Polkadot & Westend & Rococo & Statemint & Rockmine Networks (from July to December 2022)
• #1056 Subscan | Infrastructure Costs of Subscan for Polkadot & Westend & Rococo & Statemint & Rockmine Networks (from October 2023 to June 2024)
• #1366 Subscan Q3/Q4 2024 Funding Proposal: Basic service fee & Development cost for the Polkadot, Westend, and Rococo Ecosystems）

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About Subscan (Commercial) and Subscan Essentials (Open Source)

Subscan (Commercial) is a comprehensive and widely-used explorer and indexer within the Polkadot ecosystem. It provides developers, validators, parachain teams, and general users with critical data insights—enabling efficient aiding in debugging and decision-making.

Subscan Essentials is an open-source blockchain explorer framework designed for lightweight, modular, and efficient blockchain data indexing and visualization. Originally launched in 2020 with funding from the Web3 Foundation (W3F), the Subscan team has continuously maintained and improved it as a voluntary contribution to the ecosystem, without requesting additional funding for its upkeep until 2025.

Over the years, Subscan Essentials has become a widely adopted foundation for multiple blockchain explorers, providing essential infrastructure for Substrate-based ecosystems. As blockchain technology evolves, maintaining and enhancing this framework requires continuous effort to ensure stability, security, and adaptability to new developments.

Executive Summary

Recognizing the rapid evolution of blockchain technology, Subscan proposes to enhance both the open-source Subscan Essentials and its commercial platform by integrating PolkaVM (PVM) data indexing, parsing, smart contract interactions, and UI visualization. This initiative aims to deliver:

1. An open-source Substrate + PVM explorer that users can self-host, ensuring accessibility and flexibility for the community while playing a crucial role in the future of PVM interactions and cross-chain transaction.
2. An open-source PVM contract verification tool, enabling transparent and reliable contract validation.
3. Enhanced PVM support in the commercial version of Subscan Explorer, optimizing usability and performance.
4. Comprehensive user documentation, ensuring seamless adoption and ease of use.

By unifying Substrate-based data and PVM smart contract insights within a single explorer, this initiative will accelerate PVM adoption and provide the Polkadot community with a robust, user-friendly, and one-stop dashboard for on-chain exploration. 

Additionally, we are committed to supporting EVM compatibility and widely adopted industry standards, including EIPs, ensuring smooth migration and seamless tooling integration (such as Metamask, etc.) for developers deploying applications within the ecosystem.

This new module will focus on:

• Open-Source Enhancements for Subscan Essentials

• Code Refactoring & Testing: Reviewing and refactoring historical code while upgrading third-party libraries and dependencies.

• PVM Plugin Development: Developing a dedicated PVM plugin under the GPL-3.0 license to support comprehensive indexing of PVM (Revive) transactions, events, accounts, tokens, and contracts.

• React UI Components: Implementing core React UI components under the GPL-3.0 license to provide an intuitive visualization of PVM transactions, events, accounts, tokens, and contract interactions.

• PVM Smart Contract Verification: Extending the EVM smart contract verification solution to support PVM contract verification and new features, delivering an open-source verification tool under the MIT license.

  These enhancements ensure better maintainability, improved user experience, and expanded support for PVM-based ecosystems.

• Subscan Commercial Version Integration

• Built on Subscan Essentials, the commercial version will introduce an enhanced and refined UI/UX to deliver an intuitive and visually appealing interface for displaying PVM transactions, events, accounts, tokens, and contracts.

• Free API (rate limit: 5 reqs/second limit, daily request limit 100,000 reqs/d) access to core PVM data, allowing developers and users to efficiently retrieve information on transactions, events, accounts, tokens, and contracts.

• Developer-friendly UI enhancements, including the integration of a smart contract verification solution, leveraging existing Subscan open-source contract verification solution to enhance transparency and trust.

• ComGPL-3.0ment to community education and adoption, encompassing comprehensive tutorials, detailed user guides, and an iterative feedback loop to drive continuous product enhancement and ensure alignment with user needs.

Subscan commits no additional cost for any of the 90+ networks we already support if they decide to enable PVM functionality. By providing a single platform that unifies Substrate and PVM data, we aim to accelerate PolkaVM adoption and empower users to explore, verify, and analyze smart contracts with ease.

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Why This Proposal Is Necessary

1. Growing Demand for PVM Exploration
   While PolkaVM is relatively new, several networks—such as Polkadot AssetHub, Kusama AssetHub, Westend AssetHub, Paseo AssetHub, and Pop Network—have signaled plans to adopt or experiment with PVM smart contracts. However, there is currently no robust, user-friendly explorer dedicated to indexing and showcasing PVM transactions, tokens, and NFTs. Subscan’s established infrastructure can fill this gap quickly and efficiently.

2. Unified Data Access for Developers and Users
   Developers need a convenient way to monitor both Substrate extrinsics and PVM smart contracts without juggling multiple explorers. Meanwhile, end users benefit from a singular account view that shows balances, transactions, and holdings across all Polkadot-based assets. This proposal addresses these needs by integrating PVM data into Subscan’s well-known interface.

3. Lower Barriers to Contract Verification and User Education
   Accurate contract information (e.g., verified source code, function signatures) significantly reduces risk for users interacting with on-chain assets. By integrating an open-source contract verification solution into Subscan’s commercial platform, we will help ensure transparency and security while also providing user-friendly UI for verifying contracts. Additionally, we will deliver community education resources—such as how-to guides, workshops, and ongoing user support—encouraging broader PVM adoption.

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Technical Scope

Open-Source Enhancements for Subscan Essentials

Subscan will develop and open-source a dedicated PolkaVM (PVM) plugin under the GPL-3.0 license, enabling comprehensive support for the PVM ecosystem within Subscan Essentials. This plugin will introduce advanced indexing capabilities, including:

• Code Refactoring & Testing: Reviewing and refactoring historical code, upgrading third-party libraries and dependencies to enhance stability, security, and maintainability.
• PVM Transaction Indexing: Parsing and storing PVM transaction data to ensure complete traceability and accuracy.
• PVM Event Indexing: Capturing and displaying smart contract-triggered events, providing detailed event logs and state transition data.
• PVM Account Indexing: Establishing a unified account management system that integrates both Substrate-based and PVM-based accounts, offering users a consolidated account overview.
• PVM Token Indexing: Supporting smart contract-based tokens (similar to ERC-20 and ERC-721 standards), tracking total supply, token holders, transaction history, and asset movements.
• PVM Contract Indexing: Storing and displaying detailed smart contract information, including contract creation transactions, code hashes, function call records, and execution outcomes.
• PVM Smart Contract Verification Tool: Extending the EVM smart contract verification solution to support PVM contract verification and new features, ensuring developers can validate and audit smart contracts efficiently.

Additionally, Subscan Essentials will provide core UI components to enable visual representation of PVM transactions, events, accounts, tokens, and contracts, ensuring that both developers and end users can seamlessly explore and interact with PVM data.

Subscan Commercial Version Integration

Building on the open-source foundation, the commercial version of Subscan will further enhance and expand PVM ecosystem support, delivering a superior UI/UX experience, enhanced analytics, and developer-oriented features. Key improvements include:

1. Advanced UI Components
   Subscan’s commercial platform will introduce a polished and intuitive UI, ensuring seamless navigation and interactive exploration of PVM data:

• Transaction Visualization: Displays detailed transaction insights, including sender/receiver addresses, gas fees, execution status, and associated events.
• Event Visualization: Graphical representation of smart contract-triggered events, with filtering and search capabilities for improved accessibility.
• Account Visualization: Provides a unified view of Substrate and PVM accounts, allowing users to track assets, transaction histories, and interactions across different environments.
• Token Visualization: Supports comprehensive token analytics, including total supply, holder distribution, recent transactions, and NFT metadata visualization.
• Contract Visualization: Decodes smart contract interactions, displaying human-readable function calls and execution details, improving contract transparency for both developers and users.

1. Free API Access
   Subscan’s commercial version will provide free API access (rate limit: 5 reqs/second limit, daily request limit 100,000 reqs/d) to core PVM data, enabling developers to retrieve critical blockchain insights without the burden of maintaining their own indexing infrastructure. The available APIs will follow widely adopted standards, ensuring compatibility with commonly used formats such as Etherscan, making integration seamless for ecosystem developers and applications. (Final API specifications will be determined upon release.)

• /api/pvm/transactions – Retrieve PVM transaction history and execution details.

• /api/pvm/events – Query PVM event logs, with filtering options based on contract address and event type.

• /api/pvm/accounts – Fetch PVM account details, including asset holdings and transaction history.

• /api/pvm/tokens/{contract_address} – Retrieve metadata and details about specific PVM token contracts.

• /api/pvm/tokens/{contract_address}/holders – Retrieve a list of token holders for a given contract.

• /api/pvm/contracts/{contract_address} – Fetch detailed smart contract information, including verification status and interaction history.

  These APIs will offer free access to essential PVM data, ensuring that developers and users can leverage Subscan’s infrastructure to accelerate PVM ecosystem adoption within the Polkadot network.

1. Developer-Friendly UI and Smart Contract Verification
   To simplify the deployment and verification of PVM smart contracts, Subscan’s commercial version will integrate an open-source contract verification framework, providing a one-click verification tool to ensure contract transparency and security:

• Smart Contract Code Verification: Allows developers to subGPL-3.0 contract source code, verifying its authenticity against the on-chain deployed contract.

• Function Call Analysis: Decodes contract interactions, enabling users to clearly understand function calls and associated parameters.

• Event Log Parsing: Automatically extracts contract-triggered events, providing a structured and user-friendly view of execution details.

  This feature will enhance the PVM development experience while also building user trust in smart contract interactions, reducing fraud risks, and improving ecosystem security.

1. Continuous Community Education and Feedback Mechanism
   Subscan is comGPL-3.0ted to driving community education and adoption, ensuring that both developers and users can effectively navigate and utilize PVM data. Key initiatives include:

• Comprehensive Tutorials and Documentation:
  Publishing in-depth API documentation, SDK examples, and best practices to assist developers in integrating Subscan’s services.
• User Guides for General Adoption:
  Developing step-by-step guides for non-technical users on PVM account management, transaction tracking, and contract interactions.
• Interactive Feedback Mechanism:
  Encouraging community testing of the Subscan PVM module, collecting user feedback, and iteratively optimizing the product.
• Workshops & Developer Support:
  Hosting online workshops and interactive sessions to educate developers on PVM integration, smart contract best practices, and Subscan’s tooling.
  Providing technical support to early adopters, ensuring a smooth onboarding experience.

Through these efforts, Subscan aims to establish a more open, transparent, and developer-friendly PVM explorer and data service platform, contributing to the long-term growth of the Polkadot ecosystem.

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Development Workflow

We plan an 18-week (estimated) development timeline, divided into two major phases. The actual calendar dates may shift based on PolkaVM’s final release schedule. Each phase includes a user feedback cycle to ensure we build features that genuinely serve the community.

Phase 1: Open-Source Components (Approx. 8 Weeks)

Subscan Essentials Code Refactoring & Testing

Activities:

• Conduct a comprehensive audit and refactoring of legacy code to enhance maintainability, performance, and security.
• Upgrade third-party libraries and dependencies to ensure compatibility with the latest software versions and security patches.
• Optimize database queries and storage mechanisms for better indexing efficiency and reduced latency.
• Refactor core data processing modules to improve scalability and resource utilization.
• Implement unit tests, integration tests, and regression tests to validate system stability and prevent unintended behavior.
• Adopt modern coding standards and best practices to enhance readability and long-term maintainability.
• Introduce automated testing workflows and continuous integration (CI) pipelines to streamline development and deployment.
• Enhance logging and debugging mechanisms to provide better traceability and error handling.

Outcome:

• A cleaner, more efficient, and maintainable codebase.
• Improved system reliability, performance, and security, reducing technical debt.
• Faster and more accurate data indexing and retrieval within Subscan Essentials.
• Future-proofing the Subscan Essentials Explorer for ongoing enhancements and new features.

Requirements Analysis & Community Survey

Activities:

• Study final PVM specs and confirm data fields needed for indexing.
• Engage with early PVM adopters to gather user stories and developer pain points.
• Outline technical specs to align Subscan’s indexing schema with PVM transaction logs.

Outcome:

• A clear understanding of PVM data structures and user requirements.
• Roadmap for community-facing tutorials and reference guides.

Core PVM Indexer Development

Activities:

• Implement a Rust-based parser to decode PVM transactions (gas metrics, events, logs).
• Integrate indexing logic into Subscan Essentials for streamlined ingestion of block data.
• Thorough in-house testing to ensure high indexing accuracy.

Outcome:

• Reliable open-source PVM indexer with minimal performance overhead.
• Extensible architecture for future updates (e.g., additional contract standards).

Basic UI & Open-Source Release

Activities:

• Introduce a new React-based UI to enhance the user experience across various sections, including transaction details, contract pages, and token transfers, etc.
• Provide clear integration guidelines for any network looking to adopt the plugin.
• Launch an MVP environment, inviting community users to test, provide feedback, and suggest improvements.

Outcome:

• A publicly available GPL-3.0 licensed repository on Subscan Essentials GitHub.
• A more flexible and extensible UI framework, supporting both Vue and React to accommodate a wider range of development stacks.

PVM Smart Contract Verification Tool

Activities:

• Extend the EVM smart contract verification solution to support PVM contract verification and its unique features.
• Develop a standardized verification process tailored for PVM-specific contract structures and execution models.
• Implement an open-source verification tool under the MIT license to facilitate transparent and accessible contract validation.

Outcome:

• A robust and extensible PVM contract verification framework ensuring compatibility with evolving PVM standards.
• A developer-friendly open-source tool to enhance security and trust in PVM-based smart contracts.

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Phase 2: Commercial Enhancements (Approx. 10 Weeks)

Advanced Data Visualization & Dashboards

Activities:

• Create specialized analytics modules, including NFT dashboards, token holder rankings, and contract interaction charts.
• Improve the user interface and overall user experience, ensuring advanced features remain user-friendly.
• Incorporate community feedback gathered from Phase 1 to refine or add features.

Outcome:

• A premium environment with deeper insights into token metrics, NFT collections, and user behaviors.
• Higher user satisfaction through ongoing iterative improvements.

Enterprise-Grade API & Contract Verification Integration

Activities:

• Implement robust endpoints (e.g., /api/pvm/transactions) with pagination, caching, and multi-parameter queries.
• Integrate an open-source smart contract verification solution, enabling project owners to upload source code for on-chain verification.
• Provide a user-friendly UI for verifying contracts, browsing verified source code, and cross-referencing with transaction logs.

Outcome:

• Free tier for fundamental PVM data queries, ensuring broad community access.
• Additional advanced or high-volume features for enterprise clients.
• A verified contract UI that enhances transparency and trust within the ecosystem.

Community Feedback Loop & Final Adjustments

Activities:

• Publicize the integrated explorer to the PVM user community; gather bug reports, feature requests, and general feedback.
• Organize community workshops or webinars to educate users on PVM features and contract verification.
• Triage and implement improvements or fixes to close user-identified gaps.

Outcome:

• Refined product aligned with end-user expectations.
• Strengthened community relationship via education and ongoing support.

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Budget Allocation

We calculate costs using these hourly rates:

• DevOps Engineer: $75/hour
• Front-End Engineer: $75/hour
• Back-End Engineer: $75/hour
• Product Manager / Tester: $70/hour
• Designer: $70/hour

This budget reflects the best estimate of core development hours, subject to final PolkaVM specification and community feedback loops. Our final figure is around $249,250, which covers open-source development, commercial enhancements, community outreach, and contract verification integration.

Subscan’s PVM integration is structured into two key phases: Open-Source and Commercial. While we have allocated specific development hours for each role, the actual release timeline remains dependent on PolkaVM’s official schedule. As PolkaVM is still in development, any changes to its release timeline or specifications will directly impact Subscan’s roadmap.

Although our estimated effort is well-defined, the start date and final deployment will be synchronized with PolkaVM’s official progress, ensuring seamless integration and compatibility with the finalized PVM framework.

Phase 1 (Open-Source)

Role	Persons & Hours	Hourly Rate	Subtotal (USD)
Product Manager / Tester	2 person × 200 hrs	$70	US$28,000
Designer	1 person × 300 hrs	$70	US$21,000
DevOps Engineer	1 person × 240 hrs	$75	US$18,000
Front-End Engineers	2 persons × 160 hrs	$75	US$24,000
Back-End Engineers	3 persons × 370 hrs	$75	US$83,250

Subtotal (Phase 1): $174,250

Phase 2 (Commercial)

In Phase 2, we add contract verification integration tasks and expanded user feedback cycles, adding some weeks for development, front-end UI, and testing.

Role	Persons & Hours	Hourly Rate	Subtotal (USD)
Product Manager / Tester	1 person × 20 hrs	$70	$1,400
Designer	1 person × 10hrs	$70	$700
DevOps Engineer	1 person × 12hrs	$75	$900
Front-End Engineers	2 persons ×240 hrs	$75	$36,000
Back-End Engineers	2 persons ×240 hrs	$75	$36,000

Subtotal (Phase 2): $75,000

Total Estimated Cost: $174,250 + $75,000 = $249,250

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Time Calculation Logic

Actual release date = PolkaVM release cycle + Subscan PVM module development

While the full development cycle (both Open-Source and Commercial phases) will officially commence once PolkaVM reaches a stable release milestone, we will leverage publicly available information to begin preliminary development in advance. This includes analyzing disclosed specifications, prototyping key components, and preparing our indexing framework to accelerate integration once PVM is ready.

By aligning each phase with PolkaVM’s feature rollout, we ensure that Subscan’s PVM module will be functional and available as soon as PVM is live within the Polkadot ecosystem.

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Ensuring Flexibility and Alignment with PVM

Continuous Monitoring of PolkaVM Development

The Subscan team will continuously track PolkaVM’s development and remain in communication with core contributors and ecosystem partners. This allows us to anticipate potential changes in PVM’s specifications or timing and adapt our module development promptly.

Maintaining Synchronicity with Potential Spec Changes

As PolkaVM specifications evolve, especially before mainnet deployment, we will keep our architecture flexible. By doing so, we can incorporate any last-minute adjustments to ensure Subscan’s PVM integration remains fully compatible with PolkaVM’s final design.

Iterative Release Based on PVM’s Deployment Stages

• Testnet Phase: Subscan will add basic testnet support to parse and index PVM data, alongside initial UI adaptations.
• Mainnet Release: Subscan intends to offer a fully functional commercial release, including contract verification and advanced UI components, ensuring developers and end-users can leverage PVM data immediately upon mainnet launch.

In other words, the overall timeline for Subscan’s PVM integration should be viewed as “PVM stable release + the allocated open-source and commercial development hours.”

Upon PolkaVM stabilizing, we anticipate delivering a fully integrated PVM explorer (data indexing, visualization, contract verification, and comprehensive API services) within the scope of our defined open-source and commercial phases—ensuring the Polkadot community can access and analyze PVM data as soon as it becomes officially available.

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Advantages of Subscan’s Approach

1. Single Explorer for Substrate & PVM
   Users and developers gain unified visibility into both Substrate-level data (extrinsics, staking info, governance) and PVM-level smart contracts, tokens, and NFTs—all in one dashboard.

2. Immediate Community Benefit
   By releasing an open-source PVM plugin for Subscan Essentials, we empower new parachains or specialized chains to incorporate the code directly. This reduces development overhead for individual teams.

3. Integrated Contract Verification
   The commercial version will include a user-friendly UI that leverages an open-source verification framework. This helps projects provide transparency to token holders and fosters trust across the Polkadot ecosystem.

4. Ongoing Community Education & Feedback
   Subscan comGPL-3.0s to community workshops, documentation, and user surveys, ensuring the product continuously evolves to meet real-world needs.

5. Reduced Risk & Faster Time-to-Market
   We already maintain robust indexing infrastructure for 90+ networks, so adding PVM data is comparatively efficient. This lowers technical and financial risks for the Polkadot community.

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Community Involvement and Next Steps

Proposal Feedback

We invite the Polkadot community—parachain teams, developers, validators, and token holders—to review and refine this proposal. Constructive feedback will help us finalize our feature scope and cost optimizations.

Open Beta & User Testing

Once the Phase 1 MVP is complete, we will open an early testnet environment. Community members can test PVM transactions, explore verified contracts, and share suggestions for improvements or new features.

Continuous Education

Subscan will provide guides, video tutorials, and possibly online seminars on how to use PVM, how to verify contracts, and how to interpret the newly available data.

Deployment & Maintenance

Upon successful testing, the PVM plugin will be rolled out to any Subscan-supported network that enables PVM. Maintenance, updates, and user support are part of Subscan’s ongoing service comGPL-3.0ment.

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Total Requested Amount

• Subtotal (Phase 1): $174,250
• Subtotal (Phase 2): $75,000
• Total Estimated Cost: $174,250 + $75,000 = $249,250

We are requesting to make this payment using USDT, totaling $249,250 USDT.

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Conclusion

Subscan is well-equipped to deliver a comprehensive PVM explorer—from open-source foundations to advanced commercial features that include contract verification and community-focused UI enhancements. By approving this funding, Polkadot stakeholders will:

• Accelerate PVM adoption, providing immediate value to early PolkaVM networks.
• Empower developers and users with a one-stop solution for Substrate and PVM data.
• Enhance Transparency through smart contract verification, user education, and intuitive UI components.
• Foster Collaboration in the ecosystem by releasing open-source modules and offering free integrations for any of the networks that adopt PVM.

We appreciate the community’s time and consideration. Together, we can ensure Polkadot’s continued leadership in scalable, interoperable blockchain technologies—strengthening both Substrate and PolkaVM ecosystems under one powerful explorer.

We appreciate your support and valuable feedback. Your insights will help shape a robust and seamless PVM integration within Subscan, ensuring a powerful and accessible explorer for the Polkadot ecosystem. We look forward to collaborating with the community to drive innovation and adoption.