Due to potential display issues with some charts in format across various devices and platforms, please refer to the detailed information in this Google Document:

https://docs.google.com/document/d/1iAToZZz9U2j56bC6VZ_JtFuBV2FIbegvVUi4tz35C_c/edit?usp=sharing

Past discussion

https://polkadot.polkassembly.io/post/3391
Based on this discussion version, this proposal corrects some typos.

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）
• #1727 Subscan Q4 2024 – Q2 2025 Funding Proposal: Basic Service Fee & Development Cost for the Polkadot and Westend Ecosystems

Overview

Subscan requests funding from the Polkadot Treasury to support 2025 Q3–Q4 operational maintenance for the following five networks:

• Westend Relay Chain
• AssetHub-Westend
• Coretime-Westend
• BridgeHub-Westend
• People-Westend

As one of the most widely used explorers and indexing services in the Substrate ecosystem, Subscan provides essential, high-availability data infrastructure for developers, validators, governance platforms, wallets, and applications built on Westend. This proposal covers only mandatory maintenance and compatibility work, and does not include any optional enhancements or new feature development.

Cost Reduction / Discount Policy:
Owing to the ongoing infrastructure optimization work that has already demonstrated measurable improvements on our testnet deployments, Subscan is offering a 40% discount for this billing cycle. The total requested amount for Q3-Q4 is USD 21,690, reduced from the original USD 36,150. On average, this corresponds to approximately USD 723 per network per month, with each parachain costing only USD 552.6 per month. This discount is a temporary transitional measure while optimizations continue and will remain in place until the new pricing framework is launched in Q1 2026, benefiting all supported networks.

On Westend’s Transition Toward Paseo:
Subscan is aware that Westend is gradually being replaced by Paseo, and that many ecosystem teams are already transitioning. However:

• Westend is still used for certain critical operations,
  such as the recent AssetHub migration, which was first tested on Westend.
• Subscan has not received a confirmed, community-approved deprecation timeline.
• As the most widely used explorer in the ecosystem, an abrupt shutdown of Westend support would create significant disruption for developers, downstream tools, and operational pipelines.

To ensure a smooth and transparent transition, Subscan invites the community to share their preferred direction under this proposal, including:

• whether continued Westend support is still required
• what a reasonable and governance-aligned sunset timeline should be

Subscan will use the community feedback and discussion outcomes to finalize the future support plan, while ensuring developers and ecosystem participants receive sufficient notice and operational continuity during the transition period.

Recent Contributions and Ongoing Maintenance Work

Over the past several months, Subscan has continued to deliver crucial updates and maintenance work for the Westend ecosystem. Beyond providing stable explorer and indexing services, our team has:

• Completed multiple runtime upgrade adaptations across the Westend Relay Chain and all supported public parachains, ensuring uninterrupted indexing and API availability.
• Enhanced compatibility with new chain features introduced through recent upgrades, including adjustments to governance, asset management, and cross-chain messaging logic.
• Supported the October AssetHub migration on Westend, making all necessary backend modifications and data-structure updates to ensure seamless continuity for users and downstream tooling.
• Performed continuous bug fixes, data consistency checks, and indexing optimizations, keeping data quality and performance at high standards despite growing chain complexity.

Why Subscan Matters

As the default block explorer and indexing layer for Westend, Subscan provides the foundational data required by nearly all ecosystem participants.

Developers & Applications

• Reliable APIs: blocks, extrinsics, events, XCM, assets, NFTs
• Faster debugging and monitoring
• Data infrastructure for indexers, dashboards, bots, dApps

Parachain Teams & Validators

• Real-time block production, sync status, and finality
• XCM tracking across chains
• Early detection of node anomalies

Governance Platforms & Participants

• Referendum status, account history, delegation data
• Governance dashboards dependent on Subscan APIs
• Long-term auditability of past governance decisions

End Users, Wallets, and Ecosystem Tools

• Transfers, staking, NFT queries, asset visibility
• Multi-chain UI consistency and reliability

Without Subscan, many essential tools would face significant data degradation, and the accessibility of historical and governance data would be severely impacted.

Scope of This Proposal

This proposal includes the following mandatory maintenance activities:

Core Operational Maintenance

• Continuous indexing, data storage, and DB maintenance
• Multi-node redundancy and sync monitoring
• Data consistency and latency optimization

Runtime Upgrade Compatibility

• Support for upgrades on the Westend Relay Chain and all four public parachains
• Adaptation to evolving XCM, Assets, Governance, and system modules
• Ensuring zero-downtime during upgrade cycles

Essential Bug Fixing & Performance Tuning

• Schema updates and historical data alignment
• Compatibility fixes for nodes and indexers
• Performance improvements for high-load scenarios

Support for Major Ecosystem Changes

• Previously ensured smooth migration for AssetHub and recent system updates
• Future major migrations or critical runtime changes will be fully supported

Service Fee Model & Pricing Methodology

Important Notice (Updated Pricing & Testnet Optimization Rollout)：

Due to recent infrastructure optimizations that have already demonstrated measurable improvements on our testnet deployments, Subscan is applying the cost adjustments to testnet billing first, at Subscan’s own expense. We sincerely apologize for any temporary instability during the optimization testing phase.

In recognition of both the disruptions and the proven cost savings, Subscan applied a 40% discount to the original testnet service fees in the previous billing cycle as a transitional measure.

As of January 2026, Subscan has officially published the updated pricing plans, reflecting the optimization progress and delivering more stable, predictable, and cost-efficient service fees for supported networks. Moving forward, Subscan will continue refining these optimizations to further improve long-term sustainability and reduce operational overhead for the ecosystem.

Our maintenance packages are designed to support a wide range of data and operational needs while ensuring stable and efficient system performance. Because our cost structure consists of multiple infrastructure and operational components—such as cloud services, network acceleration, monitoring systems, node providers, and Subscan’s ongoing operations—we continue to use storage consumption as the primary metric for determining service fees.

2025 Pricing Tiers:
a. Basic Plan

• Up to 200 GB: $799/month
• Beyond 200 GB: $5.3/GB
• Automatically upgrades to the next tier after 350 GB

b. Advanced Plan

• Up to 500 GB: $1,699/month
• Beyond 500 GB: $5.2/GB
• Automatically upgrades to the next tier after 750 GB

c. Professional Plan

• Up to 1 TB: $2,999/month
• Beyond 1 TB: $5/GB

Monthly Service Fee Breakdown

1. Database Storage & Indexing

• What It Covers: Continuous indexing of on-chain data—from blocks and transactions to event logs, governance info, and NFTs—so users can reliably access both real-time and historical records.
  • Why It Matters: As chain activity increases, so does data volume. By tying fees to storage needs, we accurately account for the costs of scaling infrastructure (e.g., additional database capacity).

1. Network Egress Bandwidth

• What It Covers: The outgoing traffic required to serve user requests quickly and consistently, including API calls, UI data retrieval, and integrations with third-party tools.
  • Why It Matters: A stable, high-bandwidth connection ensures that explorers, wallets, and dApps receive timely data responses, even during peak activity.

1. Monitoring & DevOps

• What It Covers: Round-the-clock health checks, internal alert pipelines, CI/CD automation, and system auditing. This includes running multiple nodes, maintaining synchronization, and ensuring high availability.
  • Why It Matters: These processes help detect issues early (e.g., node crashes, indexer slowdowns) and streamline updates or deployments, minimizing service disruption for the community.

1. Node Status Monitoring & Notifications

• What It Covers: Dedicated tools and alert mechanisms to track the real-time status of network nodes—particularly those relating to the Westend Relay Chain and the associated parachains (Assethub, Coretime, Bridgehub, People).
  • Why It Matters: Quick notifications enable parachain teams, validators, and the wider ecosystem to react rapidly to performance changes, forks, or potential security incidents.

1. Technical Support & Troubleshooting

• What It Covers: Responsive assistance for users, developers, and validators, including issue resolution, feature guidance, and integration help.
  • Why It Matters: Timely support keeps the ecosystem running smoothly and fosters a positive development environment—especially crucial for teams building dApps, explorers, and automation tools.

Why We Use Storage as a Pricing Metric

Correlation to Real Costs:
Storage growth scales directly with block production and transaction activity, making it a more stable and predictable metric than raw API traffic. As chain activity evolves, storage becomes the clearest and most consistent indicator of the underlying infrastructure load required to maintain long-term historical data.

Subscan Pricing Baseline (Median-of-Period Methodology)：

Following Subscan’s established treasury billing convention, service fee tiers are determined based on the median storage usage of the requested funding period.

For the 2025 Q3–Q4 cycle, we use the Sep 30, 2025 snapshot as the representative baseline point to reflect the median-of-period storage level and to ensure consistent, predictable billing.

Predictable Billing:
Basing fees on storage reduces the volatility caused by sudden traffic spikes and ensures a more transparent, usage-based cost model for both the community and the treasury.

Beyond Storage: The Full Cost Landscape

Our pricing also incorporates the broader operational overhead required to run a production-grade, high-availability data service—such as cloud infrastructure, network acceleration, monitoring systems, node providers, and Subscan’s ongoing engineering and support efforts.

Because these components fluctuate dynamically based on cloud regions, traffic patterns, redundancy requirements, and security considerations, they cannot be broken down into a stable or meaningful line-item list. In addition, some of these details involve sensitive architectural and security-related information that should not be fully disclosed publicly in order to preserve system robustness and reduce attack surface.

For these reasons, Subscan adopts a service-fee-based pricing model, which is consistent with industry practices used by major explorer and indexing providers. Pegging the service fee to storage usage strikes the right balance between:

• transparent and verifiable metrics (storage is measurable on-chain and externally),
• predictable treasury budgeting, and
• preserving the flexibility and sustainability necessary to maintain and upgrade a mission-critical public data infrastructure.

This model also enables Subscan to invest continuously in optimization and long-term cost reduction—ensuring that infrastructure improvements directly translate into better performance and lower overall fees for the ecosystem over time.

Fee Details

2025 Q3 & Q4 Maintenance Fee

• The total maintenance fees for 2025 Q3 & Q4 (covering all 5 networks) were originally USD 36,150. After applying the 40% discount, the adjusted amount is USD 21,690.

Optimization & Cost Reduction Roadmap

To mitigate long-term storage growth and reduce operational costs—particularly for the Westend relay chain—we are executing several structural optimization initiatives. These include efforts to reduce reliance on GCP and lower total cost of ownership.

Deployment Order & Safety Strategy

To ensure data integrity and service stability during the optimization process, we follow a strict rollout sequence:

Testnet → Kusama & parachains → Polkadot & parachains

We only move to the next stage once the previous stage has been fully validated.
As a result, the cost-reduction timeline follows the same order.
Testing has already begun on the testnet networks, and the resulting cost reductions are reflected in the current billing cycle.

1. Hot/Cold storage separation

We are segmenting frequently accessed data into high-performance storage tiers while moving older blocks and events into cost-efficient archival layers.
This significantly reduces the cost of maintaining multi-terabyte historical datasets.

2. XCM-focused indexing optimizations

Given that XCM events represent a major portion of Westend’s data weight, we are optimizing:

• event-linking logic,
• redundant index structures, and
• cross-chain reference mappings.

These adjustments reduce long-term index growth without affecting query accuracy.

3. Reduced reliance on GCP (major cost-efficiency initiative)

To optimize long-term infrastructure costs, we are:

• migrating certain storage layers to lower-cost object-storage providers,
• reducing GCP I/O operations via caching and pre-aggregation strategies,
• gradually shifting parts of the system toward self-hosted or hybrid infrastructure.

These changes directly address one of the largest cost drivers in the current operational model.

Long-Term Sustainability & VisionOur long-term goal is to reduce reliance on treasury funding through multiple channels:

• Continuous optimization to limit infrastructure costs as chain data grows.
• Exploring responsible revenue streams (e.g., optional premium features or partnerships).
• Actively incorporating community suggestions to ensure value delivery aligns with user needs, increasing platform utility and potential monetization avenues without compromising openness or neutrality.

🔥 2026 Cost Outlook (Infrastructure Optimization Based)

As optimization progresses, Subscan expects to introduce more favorable and predictable pricing in Q1 2026, including:

Updated Pricing Plans (Reduced Rates vs Previous Plans)

BASIC PLAN

• $799 / Month
• Includes 500 GB / Month
• Up to ~52% lower total cost vs previous pricing at high usage

ADVANCED PLAN

• $1,699 / Month
• Includes 1 TB / Month
• Up to ~43% lower total cost vs previous pricing at high usage

Annual Payment Network Discounts (Stackable)

• Mainnet: 10% off
• Canary: 25% off
• Testnet: 40% off

2026 Estimated Annual Cost (Updated Pricing + Testnet Annual Discount)

Subscan’s goal is to provide high-quality infrastructure service with stable, predictable, and cost-efficient pricing, along with additional discounts for prepaid customers.

If the community fully transitions away from Westend and no longer requires ongoing support, Subscan plans to sunset Westend services in Q1 2026, with a proper transition process. Any transition-related costs will be subsidized by Subscan.

We also welcome feedback and suggestions from the community regarding the 2026 subscription plan. If there is strong community support for a specific approach or preferred funding structure, Subscan will follow the community’s direction and submit a separate proposal to cover the 2026 maintenance costs accordingly.

Please note that this proposal is strictly for 2025 Q3–Q4 maintenance funding only.

Total Requested Amount

The total requested amount for all 5 networks, including all maintenance, operational overhead, and mandatory compatibility work, is USD 21,690, corresponding to a 40% cost reduction from the original rate. This request will be submitted in USDT.

Conclusion

Subscan respectfully requests USD 21,690 (USDT) from the Polkadot Treasury to cover 2025 Q3–Q4 maintenance for the Westend Relay Chain and the four public parachains (AssetHub, Coretime, BridgeHub, People), ensuring continued high-availability indexing, runtime upgrade compatibility, data consistency, and stable API services required across the ecosystem.

This proposal reflects a temporary 40% discounted rate (reduced from USD 36,150) during our infrastructure optimization rollout, and it includes only essential operational work with no optional enhancements or new feature development.

To support transparent treasury decision-making and long-term planning, we have also included a 2026 cost outlook and subscription pricing framework in this proposal, enabling the community to evaluate expected future costs, discount structures, and potential transition options (including a governance-aligned sunset plan if Westend support is no longer required). Subscan welcomes community feedback on the preferred direction for Westend support and will ensure sufficient notice and service continuity throughout any transiti