The State of Sia, December 2025

This past December, we shipped reliability and networking improvements that reduce common friction points across the stack—tightening upload and connection behavior, expanding bandwidth accounting for better operational insight, strengthening SDKs for safer integrations, and pushing S3 compatibility forward so more existing tools can work with Sia-backed storage.

Looking ahead to early 2026, the Foundation shared several Grants Program administrative updates outlined in the Grants Development Guide: grants will shift to a monthly milestone structure, proposals will require a high-level architecture overview, and grantees will be expected to prioritize security best practices (e.g., credential management and access control). The first Grants Committee meeting of 2026 is scheduled for January 20th, and monthly grant progress reporting will resume at its regular cadence on January 25th.

Development Updates

indexd: Safer State Management, Richer Host Insights & Storage Lifecycle Work

This month, we focused on improving indexd’s correctness and operability with more robust scanning and metrics, safer data handling, and better lifecycle management for accounts and stored data.

Prevent the indexer from overwriting newer host prices with older ones.
Added download range support.
Fixed multiple benchmark issues to improve performance measurement and reliability.
Expanded host metrics with host version and protocol version, enabling clearer visibility into what host software is running.
Added support for soft-deleting accounts and background pruning of objects/slabs/sectors to keep storage tidy over time.
Improved object handling by including full slab metadata in objects and splitting encryption to protect metadata and object data separately.

On the UI side, indexd gained more intuitive controls—accounts can be filtered by connect key, account descriptions are surfaced in views, host and contract tables support richer multi-column sorting, and all data table columns are now resizable—making it easier to audit accounts and navigate large datasets.

Sia Storage Mobile: Background Upload Fixes, Multi-Indexer Auth & Sharing Improvements

Work on the Sia Storage Mobile app focused on reliability under real-world conditions: background execution, migrations, authentication resilience, and secure key handling.

Fixed keychain access and background timers.
Updated auth flows to support a new builder/indexer auth flow and easier indexer switching.
Added support for storing and using app keys for more than one indexer, improving multi-indexer workflows.
Improved security posture by no longer storing the recovery phrase/mnemonic, storing only a hash for verification.
Fixed shared-file import behavior and migrations to ensure local files are correctly copied to the filesystem as needed.

hostd: Bandwidth Accounting & Ongoing Storage Maintenance

hostd’s updates emphasized operational clarity and long-running stability, especially around bandwidth visibility and storage maintenance.

Added QUIC bandwidth monitoring and rate limiting.
Added monitoring for syncer bandwidth.
Introduced periodic pruning for the stored_sectors table to keep the database from accumulating unnecessary rows.

In the hostd UI we added several usability and clarity improvements. Graph rendering issues were resolved, copying of net addresses has been improved, contract menu actions will no longer select rows, and expanded helpful tips for host address configuration.

walletd: Cleaner Test Foundations & Better Rescan Feedback

We also spent some time the past month tightening up walletd developer ergonomics and reliability at the test layer.

Refactored wallet tests for maintainability.
Removed boilerplate in SQLite tests.

Updates to the walletd UI allowed for rescans to become clearer and more user-friendly. Rescan start times now display in the user’s local time, and the rescan status control now shows errors.

renterd: File Management Polish & Smoother Node UX

We enhanced the renterd UI with improvements to selection state, uploads, and operator visibility.

Deleted files/directories are now automatically removed from the active selection.
Uploads now work when browsing in All Files mode.
The onboarding wizard no longer briefly appears on initial load when onboarding is already complete.
Table control changes (filters/sorting/pagination) now reset the scroll position to ensure a more predictable workflow.
SQLite database backups can now be triggered directly from a sidenav button.

coreutils: QUIC Resilience & Partial Read Support

In coreutils we focused on improving networking robustness and more flexible sector access patterns.

Updated the mainnet bootstrap peer list.
Prevent failures when opening a QUIC stream if the stream limit is reached.
Investigated/diagnosed cases where QUIC streams weren’t being cleaned up promptly.
Updated the sectors interface to support partial reads.

These changes strengthen the foundations on which higher-level tooling relies, especially for long-running connections and efficient data access.

sia-sdk-rs: Client Abstractions & Download Stability

Our latest work on the Sia SDK advanced its core ergonomics and correctness.

Added a HostClient trait to the Rust SDK.
Fixed a potential deadlock during downloads.
Updated the Go SDK’s download code to match the Rust SDK implementation.

As noted in the repository description, this project remains in an early stage and may introduce breaking API changes.

s3d: Multipart Uploads & S3 Backend Compatibility

s3d continued moving toward broader S3 compatibility and better coverage across backends.

Improved CopyObject behavior to satisfy compatibility tests for the in-memory backend.
Added multipart upload support to the memory backend.
Added ListObjects support to the Sia store and added multipart uploads to the Sia backend.
Began testing s3d with a variety of S3 clients.
Improved benchmarking for ListObjects.

Overall, these changes make it easier for S3-native tools to interoperate with Sia-backed storage workflows.

Final Thoughts

December delivered meaningful infrastructure gains: indexd pushed forward on correctness, metrics, and lifecycle management; hostd and the web apps sharpened operational visibility and UX; work on Sia Storage tackled the hardest reliability problems around background uploads and auth; and s3d kept closing the gap toward practical S3 compatibility.

We’ll be watching closely as the ecosystem rolls into January, with Grants Program operations resuming and updated proposal expectations now in place.

That’s all, folks!

Thanks for your continued support and dedication as we build the foundation of the decentralized future.

Take care, and have a happy New Year!

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