2026-03 monthly summary for fastly/Viceroy focused on HTTP caching resilience and SDK readiness. Introduced hostcalls for stale-if-error, enabling better handling of stale responses during errors. This work improves testing, development, and SDK integration across environments.

January 2026 monthly summary for fastly repositories focused on memory safety, CI/CD reliability, and runtime caching performance. Delivered targeted code upgrades and workflow improvements with measurable impact on stability and efficiency.

December 2025 – fastly/js-compute-runtime: Delivered a critical cache range validation fix to preserve data integrity and edge performance. Implemented rejection of cache body range requests where end < start (#1182). Commit: f8957a98f458c635861b85cbccb76a715851d219. Result: prevents invalid caching, improves reliability and cache correctness for edge workloads. Repository: fastly/js-compute-runtime.

November 2025 monthly summary for fastly/Viceroy, focusing on cache reliability and SDK compatibility. Implemented a core cache alignment to ensure cache reporting follows HTTP semantics by reporting FOUND only when the object is USABLE. This change eliminates cases where FOUND is returned without USABLE, which previously caused SDKs to observe inconsistent cache state. Added targeted tests for cache expiry to validate the new behavior and prevent regressions. The work strengthens cache correctness, reduces downstream SDK bugs, and improves developer and customer trust in the caching layer.

August 2025 focused on stabilizing local development experience and advancing the 0.14.x release cycle for fastly/Viceroy. Delivered a critical bug fix to the local CLI shielding propagation, and completed a comprehensive 0.14.1 release preparation with version bumps, changelog updates, and CI/tooling upgrades, including Rust toolchain modernization and lockfile updates. These efforts improve local test fidelity, reliability of deployments, and overall developer velocity, with clear business value in faster iteration and more predictable releases.

July 2025 monthly summary for fastly/Viceroy: Delivered Cache API Range Requests Support, enabling retrieval of specific byte ranges from cached objects. Refactored cache functionalities to be asynchronous, added range-based body access methods, updated the ABI, and included tests validating correct range handling and integration. This work improves partial content delivery, bandwidth efficiency, and overall cache performance.

June 2025 performance summary: In this month, the team delivered cache-performance improvements, API usability enhancements, and test stability across core components. The enhancements in fastly/Viceroy introduce stale-while-revalidate caching and surrogate-key invalidation, improving cache hit rate and content freshness. Usability improvements remove opt-in barriers and standardize NotSupported behavior, with tests ensuring surrogate keys and range requests are properly reported as not supported. In fastly/js-compute-runtime, VCPU-ms integration tests were stabilized by refining startup timing, clarifying error messages, and correcting log spacing, reducing false failures. Collectively, these changes drive lower latency, higher availability, and more robust developer experience, enabling faster feature delivery and more reliable cache behavior.

2025-05 monthly summary for fastly/Viceroy focusing on cache reliability, safety, and cross-service parity. Delivered Core Cache API Enhancements enabling transactional cache behavior, per-entry user metadata, a strict known_length option, and safer option handling with non-impactful options ignored and privileged overrides rejected. Aligned Compute service test fixtures to run directly against Compute, addressing divergences in vary_by, cache body reading, and stale cache entries and fixing CacheBusyHandle drops. Hardened HTTP body reading with a robust read path for zero-length chunks and end-of-stream detection, supported by integration tests. These efforts improve cache correctness, service interoperability, and overall stability, delivering measurable business value through safer, more predictable caching and faster issue resolution.

April 2025 monthly summary: Delivered core HTTP cache enhancements in fastly/Viceroy and improved backend TLS certificate validation documentation in fastly/js-compute-runtime, with an emphasis on business value, reliability, and developer clarity. Key work included streaming HTTP bodies for concurrent write/read (CollectingBody), partial non-transactional cache API behind an environment gate, and cache aging/Vary semantics to ensure fresh, correct responses based on request headers; accompanied by tests gated behind an env flag to manage risk. Documentation improved for CA certificate validation to clarify checks, hostname matching, and use of custom CA certificates, strengthening backend TLS security guidance. Major items delivered: - HTTP Cache Core Enhancements (Viceroy): streaming CollectingBody, partial API, cache aging, Vary semantics; commits: d8632a0f7d25249193b84d355b474d2ad2fe1326; 6e52c6d74e6476010efd0f6920df2f1d87350463; 5bc95a1cf1a1faa5144165b9f2961ef0998206e2. - TLS validation documentation (js-compute-runtime): clarified CA checks, hostname matching, and custom CA usage; commit: b5fa57e02fa984302af9ab95b6f1971257296e0d.

March 2025 monthly summary for fastly/Viceroy: Delivered robust test environment improvements, updated CI infrastructure to Ubuntu 24.04, and fixed a critical cache key type mismatch. These changes increased test robustness, CI stability, and data correctness, aligning with performance and reliability goals.

February 2025 monthly summary for fastly/Viceroy: CI/toolchain stabilization, major bug fix in the build pipeline, and stronger release reliability.