
Over the past 18 months, Jan S. Najdř has delivered robust engineering solutions across the WordPress/gutenberg and Automattic/wp-calypso repositories, focusing on editor reliability, build optimization, and accessibility. Jan refactored core modules using JavaScript and TypeScript, modernized styling with CSS modules, and improved API integration for content workflows. His work included enhancing theme color accuracy, streamlining asset loading, and strengthening test coverage to reduce regressions. By migrating to ESM and updating build tooling, Jan improved release reliability and maintainability. These efforts resulted in faster development cycles, more accessible interfaces, and a stable foundation for future feature delivery and codebase evolution.
March 2026 monthly summary for Automattic/gutenberg: Delivered two key features focused on reliability and editor robustness, with targeted tests and clear business impact. Improved sync reliability via API-based updates and strengthened iframe editor workflows, leading to more stable editing experiences and easier maintenance.
March 2026 monthly summary for Automattic/gutenberg: Delivered two key features focused on reliability and editor robustness, with targeted tests and clear business impact. Improved sync reliability via API-based updates and strengthened iframe editor workflows, leading to more stable editing experiences and easier maintenance.
February 2026 at Automattic/gutenberg delivered key platform improvements across versioning, React 19 compatibility, and editor stability. Business value was realized through improved pre-release tracking (timestamped publishing), reduced release risk via React 19/type-safety enhancements, and performance/stability gains in the editor, supported by broader test coverage and modernization (Emotion, TS, Storybook).
February 2026 at Automattic/gutenberg delivered key platform improvements across versioning, React 19 compatibility, and editor stability. Business value was realized through improved pre-release tracking (timestamped publishing), reduced release risk via React 19/type-safety enhancements, and performance/stability gains in the editor, supported by broader test coverage and modernization (Emotion, TS, Storybook).
January 2026: Delivered stability, modernization, and performance improvements for WordPress/gutenberg across tooling, build infrastructure, theming, and release processes. Key outcomes include stabilization of Node.js tooling with a clear upgrade/rollback policy, modernization of the core build (ESM/.mjs, ESLint, module resolution, and dependency upgrades with SlotFill enhancements), theme color system improvements with tests and bundle optimizations, date handling performance improvements via corrected timezone usage and pre-built bundles, and release management/API cleanup with a new preid scheme and API surface reductions. These changes reduce build flakiness, shrink bundles, and accelerate development cycles, while strengthening long-term modularity and deployment practices.
January 2026: Delivered stability, modernization, and performance improvements for WordPress/gutenberg across tooling, build infrastructure, theming, and release processes. Key outcomes include stabilization of Node.js tooling with a clear upgrade/rollback policy, modernization of the core build (ESM/.mjs, ESLint, module resolution, and dependency upgrades with SlotFill enhancements), theme color system improvements with tests and bundle optimizations, date handling performance improvements via corrected timezone usage and pre-built bundles, and release management/API cleanup with a new preid scheme and API surface reductions. These changes reduce build flakiness, shrink bundles, and accelerate development cycles, while strengthening long-term modularity and deployment practices.
December 2025 performance snapshot for WordPress/gutenberg. Delivered major styling migrations, build system enhancements, and theming improvements across core editing and theming surfaces. Focused on replacing Emotion with CSS modules and inline styles for UI stability, improving color accuracy in themes, and hardening build/packaging for faster, more reliable releases. Also addressed test reliability and changelog/documentation to reduce regressions.
December 2025 performance snapshot for WordPress/gutenberg. Delivered major styling migrations, build system enhancements, and theming improvements across core editing and theming surfaces. Focused on replacing Emotion with CSS modules and inline styles for UI stability, improving color accuracy in themes, and hardening build/packaging for faster, more reliable releases. Also addressed test reliability and changelog/documentation to reduce regressions.
Delivered two major Gutenberg initiatives in 2025-11: Theme Color Ramp Accessibility and Contrast Enhancements and Asset Loading Performance Refactor. Key outcomes include improved accessibility with logarithmic contrast calculations, updated color ramp generation, and enhanced reporting of unmet contrast targets; plus a comprehensive buildRamps test suite. Asset loading was refactored to load scripts in the body/footer, yielding faster render and cleaner asset graph. Strengthened test coverage, updated snapshots, and trunk stabilization efforts via test adjustments. Demonstrated strong collaboration across WordPress JS/CSS/code quality practices. Business value: stronger accessibility compliance, more consistent visual rendering, and measurable performance gains for page loads, contributing to better user experience and reduced support cost.
Delivered two major Gutenberg initiatives in 2025-11: Theme Color Ramp Accessibility and Contrast Enhancements and Asset Loading Performance Refactor. Key outcomes include improved accessibility with logarithmic contrast calculations, updated color ramp generation, and enhanced reporting of unmet contrast targets; plus a comprehensive buildRamps test suite. Asset loading was refactored to load scripts in the body/footer, yielding faster render and cleaner asset graph. Strengthened test coverage, updated snapshots, and trunk stabilization efforts via test adjustments. Demonstrated strong collaboration across WordPress JS/CSS/code quality practices. Business value: stronger accessibility compliance, more consistent visual rendering, and measurable performance gains for page loads, contributing to better user experience and reduced support cost.
Monthly performance summary for 2025-10 focusing on wp-calypso release readiness and dependency hygiene. Key readiness work completed to publish wpcom 7.0.1 and prepare wpcom-xhr-request 1.3.0; infrastructure fixes to ensure clean builds and minimal publish blockers.
Monthly performance summary for 2025-10 focusing on wp-calypso release readiness and dependency hygiene. Key readiness work completed to publish wpcom 7.0.1 and prepare wpcom-xhr-request 1.3.0; infrastructure fixes to ensure clean builds and minimal publish blockers.
September 2025 — WordPress Gutenberg: Key reliability and test improvements underpinning more stable content fetching and slug handling. Implemented robust api-fetch improvements with refactored unit tests, enhanced error handling for non-JSON responses, nonce refresh propagation, and expanded coverage. Fixed template creation issues with long/encoded slugs by decoding URI components before prefixing. Commits delivered: d528cec42732702f8ef66ef20dc46e8494299107 (api-fetch: cleanup and improve unit tests (#71439)); 2646370b28ffaf1a7048f688cbe13491ed6e0379 (api-fetch: clean up error handling (#71458)); 89b95e1d21def2a172199ed5df70879aeab7b97a (Fix creating templates for posts with long slugs (#71838)). Impact: reduces runtime failures in API interactions, minimizes template creation errors, speeds QA cycles, and improves UX for content authors. Technologies/skills demonstrated: JavaScript/React (WordPress Gutenberg), unit testing, error handling, URI encoding/decoding, code refactoring, test-driven development, CI readiness.
September 2025 — WordPress Gutenberg: Key reliability and test improvements underpinning more stable content fetching and slug handling. Implemented robust api-fetch improvements with refactored unit tests, enhanced error handling for non-JSON responses, nonce refresh propagation, and expanded coverage. Fixed template creation issues with long/encoded slugs by decoding URI components before prefixing. Commits delivered: d528cec42732702f8ef66ef20dc46e8494299107 (api-fetch: cleanup and improve unit tests (#71439)); 2646370b28ffaf1a7048f688cbe13491ed6e0379 (api-fetch: clean up error handling (#71458)); 89b95e1d21def2a172199ed5df70879aeab7b97a (Fix creating templates for posts with long slugs (#71838)). Impact: reduces runtime failures in API interactions, minimizes template creation errors, speeds QA cycles, and improves UX for content authors. Technologies/skills demonstrated: JavaScript/React (WordPress Gutenberg), unit testing, error handling, URI encoding/decoding, code refactoring, test-driven development, CI readiness.
August 2025 was focused on a key refactor in WordPress/gutenberg within the core-data package. The Entity Reducer Generation logic was simplified by replacing an iterative reduce with Object.fromEntries to dynamically generate reducers based on entity configurations. This improves maintainability, readability, and provides a cleaner foundation for future entity-driven changes, while preserving functionality.
August 2025 was focused on a key refactor in WordPress/gutenberg within the core-data package. The Entity Reducer Generation logic was simplified by replacing an iterative reduce with Object.fromEntries to dynamically generate reducers based on entity configurations. This improves maintainability, readability, and provides a cleaner foundation for future entity-driven changes, while preserving functionality.
Summary for July 2025: Delivered critical dev-environment and editor improvements for Gutenberg, emphasizing reliability, user-config protection, and smoother in-editor navigation. Key outcomes include automatic WP-CLI config creation during environment setup to ensure correct mod_rewrite and multisite behavior; safeguarding existing user WP-CLI configurations by preventing overwrites; and enhancement of the iframe-based editor to intercept hash links for smooth scrolling to internal anchors without page reloads. These changes reduce setup friction, prevent user-config loss, and improve editorial UX in development environments.
Summary for July 2025: Delivered critical dev-environment and editor improvements for Gutenberg, emphasizing reliability, user-config protection, and smoother in-editor navigation. Key outcomes include automatic WP-CLI config creation during environment setup to ensure correct mod_rewrite and multisite behavior; safeguarding existing user WP-CLI configurations by preventing overwrites; and enhancement of the iframe-based editor to intercept hash links for smooth scrolling to internal anchors without page reloads. These changes reduce setup friction, prevent user-config loss, and improve editorial UX in development environments.
June 2025 performance summary focusing on key features, architectural improvements, and business value. Delivered two targeted enhancements across Gutenberg and wp-calypso, emphasizing modularity, type safety, and future-proofing. No explicit bug fixes were documented this month; instead, major efforts focused on architectural refactors and safer module resolution to reduce risk and speed up future delivery.
June 2025 performance summary focusing on key features, architectural improvements, and business value. Delivered two targeted enhancements across Gutenberg and wp-calypso, emphasizing modularity, type safety, and future-proofing. No explicit bug fixes were documented this month; instead, major efforts focused on architectural refactors and safer module resolution to reduce risk and speed up future delivery.
Monthly summary for May 2025 focusing on Automattic/wp-calypso development. Key outcomes include hardening Redux state access, improving privacy controls, modernizing authentication flows with hooks, refining subscriber UI/config, and upgrading packaging/build tooling to streamline releases. These changes reduce runtime warnings, prevent unintended state mutations, improve startup readiness, and simplify feature flag management, enabling faster delivery and lower maintenance costs.
Monthly summary for May 2025 focusing on Automattic/wp-calypso development. Key outcomes include hardening Redux state access, improving privacy controls, modernizing authentication flows with hooks, refining subscriber UI/config, and upgrading packaging/build tooling to streamline releases. These changes reduce runtime warnings, prevent unintended state mutations, improve startup readiness, and simplify feature flag management, enabling faster delivery and lower maintenance costs.
April 2025 highlights across Automattic/wp-calypso and Automattic/jetpack. Delivered major tooling, API reliability improvements, i18n modernization, UI/UX refinements, and cross-repo packaging/enhancements. These efforts reduce onboarding effort, improve code quality, and enable broader compatibility with modern module formats and core WordPress libraries, while delivering a more consistent user experience across platforms.
April 2025 highlights across Automattic/wp-calypso and Automattic/jetpack. Delivered major tooling, API reliability improvements, i18n modernization, UI/UX refinements, and cross-repo packaging/enhancements. These efforts reduce onboarding effort, improve code quality, and enable broader compatibility with modern module formats and core WordPress libraries, while delivering a more consistent user experience across platforms.
March 2025 performance summary for Automattic repositories (wp-calypso and jetpack). Key features delivered include VAT Details Visible by Default in Purchases, and targeted code quality improvements in wp-calypso; plus reliability and UX enhancements in Jetpack such as notifications routing fixes and Likes module improvements. These efforts improve billing transparency, code maintainability, localization readiness, and overall user experience across WordPress.com ecosystems. Technologies demonstrated include TypeScript/JS refactors, API namespace handling, Stylelint-based CSS quality, and cross-repo quality improvements.
March 2025 performance summary for Automattic repositories (wp-calypso and jetpack). Key features delivered include VAT Details Visible by Default in Purchases, and targeted code quality improvements in wp-calypso; plus reliability and UX enhancements in Jetpack such as notifications routing fixes and Likes module improvements. These efforts improve billing transparency, code maintainability, localization readiness, and overall user experience across WordPress.com ecosystems. Technologies demonstrated include TypeScript/JS refactors, API namespace handling, Stylelint-based CSS quality, and cross-repo quality improvements.
February 2025 performance highlights across Automattic/wp-calypso and Automattic/jetpack, focused on codebase modernization, reliability, and UX consistency. Key outcomes include internal codebase modernization and bootstrapping simplification, dynamic assets hot reload with race-condition prevention, and the removal of legacy social features. Also, a targeted UX/flag cleanup in Jetpack to ensure consistent likes widget display across environments. These changes reduce operational risk, improve maintainability, and accelerate future feature work.
February 2025 performance highlights across Automattic/wp-calypso and Automattic/jetpack, focused on codebase modernization, reliability, and UX consistency. Key outcomes include internal codebase modernization and bootstrapping simplification, dynamic assets hot reload with race-condition prevention, and the removal of legacy social features. Also, a targeted UX/flag cleanup in Jetpack to ensure consistent likes widget display across environments. These changes reduce operational risk, improve maintainability, and accelerate future feature work.
January 2025 performance summary for Automattic/wp-calypso. The month focused on delivering user-facing capabilities while simplifying feature governance, speeding initial renders, and strengthening the maintainability of core subscriber/reader flows. Key business outcomes include immediate activation of essential subscriber features (CSV upload and gifting) without feature flags, reduced API chatter through debounced search, and improved page load performance via preloading. In addition, substantial groundwork was laid to modernize data handling and routing (thunks-based stores and login flow cleanup), setting a solid foundation for faster onboarding and future UX improvements.
January 2025 performance summary for Automattic/wp-calypso. The month focused on delivering user-facing capabilities while simplifying feature governance, speeding initial renders, and strengthening the maintainability of core subscriber/reader flows. Key business outcomes include immediate activation of essential subscriber features (CSV upload and gifting) without feature flags, reduced API chatter through debounced search, and improved page load performance via preloading. In addition, substantial groundwork was laid to modernize data handling and routing (thunks-based stores and login flow cleanup), setting a solid foundation for faster onboarding and future UX improvements.
December 2024: Delivered key features enhancing reliability and performance of the WordPress editing experience, improved build efficiency, and clarified developer guidance. Achievements include SlotFill system enhancements with observableMap, DataViews build/externalization and tree-shaking improvements, and private API documentation. Fixed identity warning in CreateTemplatePartModalContents and strengthened type safety. wp-calypso work reduced bundle sizes through externals, bundled React JSX runtime for older WP versions, and optimized site data fetch while cleaning up deprecated Query block observers. Business impact: faster load times, smaller bundles, and clearer developer guidance enabling faster feature delivery.
December 2024: Delivered key features enhancing reliability and performance of the WordPress editing experience, improved build efficiency, and clarified developer guidance. Achievements include SlotFill system enhancements with observableMap, DataViews build/externalization and tree-shaking improvements, and private API documentation. Fixed identity warning in CreateTemplatePartModalContents and strengthened type safety. wp-calypso work reduced bundle sizes through externals, bundled React JSX runtime for older WP versions, and optimized site data fetch while cleaning up deprecated Query block observers. Business impact: faster load times, smaller bundles, and clearer developer guidance enabling faster feature delivery.
November 2024 performance summary: Delivered major stability and robustness enhancements across Gutenberg and Calypso. Key features include SlotFill system improvements with refactors and API cleanup, post type rendering safeguards to prevent fatal errors, and a Redux upgrade to v5.0.1. In Automattic/wp-calypso, implemented a URL routing fix to normalize leading slashes and avoid misinterpretation as external links. These efforts reduce editing-time errors, improve content editing reliability, and position the codebase for faster iteration.
November 2024 performance summary: Delivered major stability and robustness enhancements across Gutenberg and Calypso. Key features include SlotFill system improvements with refactors and API cleanup, post type rendering safeguards to prevent fatal errors, and a Redux upgrade to v5.0.1. In Automattic/wp-calypso, implemented a URL routing fix to normalize leading slashes and avoid misinterpretation as external links. These efforts reduce editing-time errors, improve content editing reliability, and position the codebase for faster iteration.
Month: 2024-10 — Gutenberg repository (Automattic/gutenberg) focus: performance optimization and API hygiene. Delivered two feature cleanups with clear business value: PostCSS Import Optimization to reduce bundle size while preserving style transformation behavior, and Private API Cleanup for WordPress Interface to remove obsolete private API usage. These changes improve build efficiency, reduce technical debt, and align with future interface standards.
Month: 2024-10 — Gutenberg repository (Automattic/gutenberg) focus: performance optimization and API hygiene. Delivered two feature cleanups with clear business value: PostCSS Import Optimization to reduce bundle size while preserving style transformation behavior, and Private API Cleanup for WordPress Interface to remove obsolete private API usage. These changes improve build efficiency, reduce technical debt, and align with future interface standards.

Overview of all repositories you've contributed to across your timeline