mbta/orbit
Dec 2024 – Mar 2026
11 Months active
Languages Used
ElixirJavaScriptTypeScriptCSSHTMLSQLZodtsx
Technical Skills
Backend DevelopmentCode LintingConfiguration ManagementFrontend DevelopmentFull Stack DevelopmentReact
Preston Mueller
PROFILE
Preston Mueller
Over an 11-month period, contributed to mbta/orbit by building real-time train tracking, robust certification management, and secure access control features. Leveraging Elixir, React, and TypeScript, delivered end-to-end data flows for live vehicle positions and trip updates using WebSockets and centralized state management. Enhanced backend reliability with distributed Elixir clustering, database migrations, and permission refactoring, while improving frontend usability through UI refinements and routing upgrades. Addressed data integrity and observability with telemetry, Sentry integration, and diagnostics tooling. Maintained code quality with ESLint, test-driven development, and configuration management, supporting maintainable, scalable operations and streamlined onboarding for both users and developers.
Overall Statistics
Feature vs Bugs
83%Features
Repository Contributions
54Total
Bugs
5
Commits
54
Features
24
Lines of code
10,252
Activity Months11
Your Network
32 peopleWork History
March 2026
6 Commits • 4 Features
Mar 1, 2026March 2026: Delivered reliability and usability enhancements for mbta/orbit. Implemented Live Dashboard with admin access control, distributed Elixir operation with DNS clustering and leader-based event handling to prevent duplicates, ensured a single global Orbit.Ocs.Supervisor per cluster via Highlander, and refreshed CLI environment config and dependencies for maintainability. These changes improve operator UX, deployment safety, and future scalability.
6 Commits • 4 Features
Mar 1, 2026March 2026: Delivered reliability and usability enhancements for mbta/orbit. Implemented Live Dashboard with admin access control, distributed Elixir operation with DNS clustering and leader-based event handling to prevent duplicates, ensured a single global Orbit.Ocs.Supervisor per cluster via Highlander, and refreshed CLI environment config and dependencies for maintainability. These changes improve operator UX, deployment safety, and future scalability.
March 2026
January 2026
4 Commits • 2 Features
Jan 1, 2026Concise monthly summary for 2026-01 focusing on mbta/orbit business value and technical achievements. Delivered platform upgrades, observability improvements, and process enhancements that improve stability, release readiness, and developer efficiency. Key work centered on upgrading core tech, improving test reliability, and strengthening review workflows to accelerate safe deployments.
January 2026
4 Commits • 2 Features
Jan 1, 2026Concise monthly summary for 2026-01 focusing on mbta/orbit business value and technical achievements. Delivered platform upgrades, observability improvements, and process enhancements that improve stability, release readiness, and developer efficiency. Key work centered on upgrading core tech, improving test reliability, and strengthening review workflows to accelerate safe deployments.
November 2025
1 Commits • 1 Features
Nov 1, 2025Month: 2025-11 — Summary: Delivered SEO Indexing Control for mbta/orbit by removing robots.txt and adding a noindex meta tag to govern search engine indexing and exposure. This feature aligns with SEO governance and reduces risk of unintended indexing. Implemented via commit bb5383857e1adb26ba85a764f79993c34ddb4508 (fix: switch from robots.txt to noindex, #418). No separate major bugs reported this month; the work focuses on strategic indexing control with clean rollout. Technologies/skills demonstrated include HTML meta tagging, indexing policy application, Git workflow, and change management for SEO.
1 Commits • 1 Features
Nov 1, 2025Month: 2025-11 — Summary: Delivered SEO Indexing Control for mbta/orbit by removing robots.txt and adding a noindex meta tag to govern search engine indexing and exposure. This feature aligns with SEO governance and reduces risk of unintended indexing. Implemented via commit bb5383857e1adb26ba85a764f79993c34ddb4508 (fix: switch from robots.txt to noindex, #418). No separate major bugs reported this month; the work focuses on strategic indexing control with clean rollout. Technologies/skills demonstrated include HTML meta tagging, indexing policy application, Git workflow, and change management for SEO.
November 2025
August 2025
2 Commits • 1 Features
Aug 1, 2025Month: 2025-08 — Delivered key frontend improvements in mbta/orbit with a focus on access control and UI polish. The changes support broader user access to critical features while enhancing visual consistency, delivered with clear, issue-tracked commits for maintainability.
August 2025
2 Commits • 1 Features
Aug 1, 2025Month: 2025-08 — Delivered key frontend improvements in mbta/orbit with a focus on access control and UI polish. The changes support broader user access to critical features while enhancing visual consistency, delivered with clear, issue-tracked commits for maintainability.
July 2025
13 Commits • 4 Features
Jul 1, 2025July 2025 performance summary for mbta/orbit: Implemented end-to-end real-time data fusion for vehicle positions and trip updates, introduced TripMatcherServer and frontend useVehicles, and delivered real-time trip rendering with actual departures and delay indicators, alongside UI refinements for current/next trips and refined departure-time logic and tests. Added robust monitoring and debugging capabilities via TripMatcher statistics/diagnostics and OCS debugging pages, and introduced VehicleEventDetector to persist arrival/departure events. Fixed critical edge cases affecting departure application, TripUpdate association, and late-box handling to improve data integrity and reliability.
13 Commits • 4 Features
Jul 1, 2025July 2025 performance summary for mbta/orbit: Implemented end-to-end real-time data fusion for vehicle positions and trip updates, introduced TripMatcherServer and frontend useVehicles, and delivered real-time trip rendering with actual departures and delay indicators, alongside UI refinements for current/next trips and refined departure-time logic and tests. Added robust monitoring and debugging capabilities via TripMatcher statistics/diagnostics and OCS debugging pages, and introduced VehicleEventDetector to persist arrival/departure events. Fixed critical edge cases affecting departure application, TripUpdate association, and late-box handling to improve data integrity and reliability.
July 2025
June 2025
9 Commits • 3 Features
Jun 1, 2025June 2025 Monthly Summary (mbta/orbit) Overview: Delivered three focused feature areas with a strong emphasis on user experience, security, and data model foundation. The work supports safer operations, faster navigation, and scalable data capture for operational control data. Key features delivered: - Ladder Page UI Enhancements: refined ladder display with adjusted padding, added horizontal scroll snapping, highlighted the active train when the sidebar is open, and introduced a new Current Trip section in the ladder page sidebar to provide quick context. - Access Control and Permissions Enhancements: tightened interaction restrictions for unauthorized users, introduced ORBIT_TID_STAFF group, refactored permission checks, and updated route protections to ensure secure access control across the UI and backend. - OCS Data Model: Trips and Trains: added ocs_trips and ocs_trains tables with schema, migrations, and tests to store and validate operational control data. Major bugs fixed (and refinements): - UI padding adjustments for ladder component to improve consistency across screen sizes (fix(ladder): reduce padding overall + remove it on small screen). - Permission-related UI behavior: disabled train pill pointer cursor when user lacks permission. - Permission/group routing fixes: additional groups fixes and ensuring orbit_tid_staff is honored in BL backend routes. - Backend routing alignment: ensuring orbit_tid_staff is wired into relevant backend protections. Overall impact and accomplishments: - Improved operational usability: faster, more intuitive ladder navigation and quick visibility of current trips. - Strengthened security and compliance posture: clearer permission boundaries and robust route protections reduce risk of unauthorized actions. - Foundational data model established: newly created ocs_trips and ocs_trains tables enable reliable storage and testing for OCC/OCS-related operations, paving the way for analytics and reporting. - Sustainable, observable progress: commits across three feature areas demonstrate end-to-end delivery from UI to permissions and data models, with testing and migrations in place. Technologies and skills demonstrated: - Frontend/UI: React-based ladder improvements, CSS/padding adjustments, scroll-snap implementation, dynamic active-state highlighting. - Access control/security: permission checks, user group modeling (ORBIT_TID_STAFF), and route protections. - Backend/data modeling: database schema design, migrations, and tests for ocs_trips and ocs_trains; route integration for staff group. - Quality: incremental commits with focused scope, feature flags-like behavior via UI state, and test coverage implied by migrations and tests. Business value: - Delivers tangible improvements to operator workflows and decision support with the ladder UI and sidebar context. - Reduces security risk by enforcing appropriate access controls and protecting critical routes. - Enables robust operational data management to support future analytics, reporting, and operational decision-making.
June 2025
9 Commits • 3 Features
Jun 1, 2025June 2025 Monthly Summary (mbta/orbit) Overview: Delivered three focused feature areas with a strong emphasis on user experience, security, and data model foundation. The work supports safer operations, faster navigation, and scalable data capture for operational control data. Key features delivered: - Ladder Page UI Enhancements: refined ladder display with adjusted padding, added horizontal scroll snapping, highlighted the active train when the sidebar is open, and introduced a new Current Trip section in the ladder page sidebar to provide quick context. - Access Control and Permissions Enhancements: tightened interaction restrictions for unauthorized users, introduced ORBIT_TID_STAFF group, refactored permission checks, and updated route protections to ensure secure access control across the UI and backend. - OCS Data Model: Trips and Trains: added ocs_trips and ocs_trains tables with schema, migrations, and tests to store and validate operational control data. Major bugs fixed (and refinements): - UI padding adjustments for ladder component to improve consistency across screen sizes (fix(ladder): reduce padding overall + remove it on small screen). - Permission-related UI behavior: disabled train pill pointer cursor when user lacks permission. - Permission/group routing fixes: additional groups fixes and ensuring orbit_tid_staff is honored in BL backend routes. - Backend routing alignment: ensuring orbit_tid_staff is wired into relevant backend protections. Overall impact and accomplishments: - Improved operational usability: faster, more intuitive ladder navigation and quick visibility of current trips. - Strengthened security and compliance posture: clearer permission boundaries and robust route protections reduce risk of unauthorized actions. - Foundational data model established: newly created ocs_trips and ocs_trains tables enable reliable storage and testing for OCC/OCS-related operations, paving the way for analytics and reporting. - Sustainable, observable progress: commits across three feature areas demonstrate end-to-end delivery from UI to permissions and data models, with testing and migrations in place. Technologies and skills demonstrated: - Frontend/UI: React-based ladder improvements, CSS/padding adjustments, scroll-snap implementation, dynamic active-state highlighting. - Access control/security: permission checks, user group modeling (ORBIT_TID_STAFF), and route protections. - Backend/data modeling: database schema design, migrations, and tests for ocs_trips and ocs_trains; route integration for staff group. - Quality: incremental commits with focused scope, feature flags-like behavior via UI state, and test coverage implied by migrations and tests. Business value: - Delivers tangible improvements to operator workflows and decision support with the ladder UI and sidebar context. - Reduces security risk by enforcing appropriate access controls and protecting critical routes. - Enables robust operational data management to support future analytics, reporting, and operational decision-making.
May 2025
4 Commits • 3 Features
May 1, 2025During May 2025, mbta/orbit delivered tangible improvements in real-time data delivery, data integrity, and routing maintainability, with a focus on reliability, performance, and developer productivity. Key outcomes include real-time frontend trip updates via WebSocket, fixes to frontend vehicle positions data structure to eliminate initial delays, a precise map positioning utility with unit tests, and a React Router v7 upgrade. These efforts improved user visibility into live trip status, reduced latency in status updates, ensured correctness of map rendering, and reduced maintenance burden through modernized routing infrastructure.
4 Commits • 3 Features
May 1, 2025During May 2025, mbta/orbit delivered tangible improvements in real-time data delivery, data integrity, and routing maintainability, with a focus on reliability, performance, and developer productivity. Key outcomes include real-time frontend trip updates via WebSocket, fixes to frontend vehicle positions data structure to eliminate initial delays, a precise map positioning utility with unit tests, and a React Router v7 upgrade. These efforts improved user visibility into live trip status, reduced latency in status updates, ensured correctness of map rendering, and reduced maintenance burden through modernized routing infrastructure.
May 2025
April 2025
4 Commits • 1 Features
Apr 1, 2025During April 2025, mbta/orbit delivered real-time train position tracking and visualization on the ladder page, enabling live, accurate display of train positions through a WebSocket-based data flow and centralized socket management. Key architectural improvements include introducing a SocketProvider to replace the previous initSocket approach, establishing a WebSocket feed for vehicle positions, and modeling updates to support real-time status rendering. A new Train component was added to visualize positions, and the frontend data flow was wired by hooking useVehiclePositions to the VehiclePosition model, laying the groundwork for future telemetry features. This work collectively improves situational awareness for operators and reduces latency between data generation and user presentation.
April 2025
4 Commits • 1 Features
Apr 1, 2025During April 2025, mbta/orbit delivered real-time train position tracking and visualization on the ladder page, enabling live, accurate display of train positions through a WebSocket-based data flow and centralized socket management. Key architectural improvements include introducing a SocketProvider to replace the previous initSocket approach, establishing a WebSocket feed for vehicle positions, and modeling updates to support real-time status rendering. A new Train component was added to visualize positions, and the frontend data flow was wired by hooking useVehiclePositions to the VehiclePosition model, laying the groundwork for future telemetry features. This work collectively improves situational awareness for operators and reduces latency between data generation and user presentation.
February 2025
1 Commits • 1 Features
Feb 1, 2025February 2025 — mbta/orbit: Key features delivered and impact. The primary deliverable was a Certification Status Modeling Refactor that encapsulates expired and missing certifications into a new CertificationStatus type. This centralizes certification state logic and simplifies data flows to Attestation, Expiry, and OperatorSignInModalContent, reducing cross-component coupling and enabling safer downstream changes. This work is tracked by commit 398699c361b362ba86ad0e9d9ca158386e4ff3a4 (#244). Overall impact: improved maintainability, fewer inconsistencies in certification handling, and clearer data contracts across authentication and attestation features. Technologies/skills demonstrated: type-system-driven refactor, centralized data modeling, and commit-based traceability in a single repo.
1 Commits • 1 Features
Feb 1, 2025February 2025 — mbta/orbit: Key features delivered and impact. The primary deliverable was a Certification Status Modeling Refactor that encapsulates expired and missing certifications into a new CertificationStatus type. This centralizes certification state logic and simplifies data flows to Attestation, Expiry, and OperatorSignInModalContent, reducing cross-component coupling and enabling safer downstream changes. This work is tracked by commit 398699c361b362ba86ad0e9d9ca158386e4ff3a4 (#244). Overall impact: improved maintainability, fewer inconsistencies in certification handling, and clearer data contracts across authentication and attestation features. Technologies/skills demonstrated: type-system-driven refactor, centralized data modeling, and commit-based traceability in a single repo.
February 2025
January 2025
8 Commits • 3 Features
Jan 1, 2025January 2025 contributions focused on scalable certification management, data integrity, and improved observability for mbta/orbit. Delivered a robust employee certifications import workflow, enhanced operator sign-in controls with expiry handling and overrides, tightened data integrity for rail_line associations, and improved system visibility through Sentry context and telemetry for Oban jobs and Phoenix sockets. These changes deliver stronger compliance, faster onboarding validations, and better operational insight for incident response and decision-making.
January 2025
8 Commits • 3 Features
Jan 1, 2025January 2025 contributions focused on scalable certification management, data integrity, and improved observability for mbta/orbit. Delivered a robust employee certifications import workflow, enhanced operator sign-in controls with expiry handling and overrides, tightened data integrity for rail_line associations, and improved system visibility through Sentry context and telemetry for Oban jobs and Phoenix sockets. These changes deliver stronger compliance, faster onboarding validations, and better operational insight for incident response and decision-making.
December 2024
2 Commits • 1 Features
Dec 1, 2024Month: 2024-12 — mbta/orbit monthly summary: Delivered Appcues integration and page tracking in production, including a new React component to track page views and identify users for Appcues. Also cleaned ESLint configuration by removing redundant TypeScript error suppressions across plugins, improving maintainability. Impact: enabled onboarding/engagement analytics and reduced technical debt; improved code quality and production readiness. Technologies/skills demonstrated: React, TypeScript, Appcues integration, ESLint/config management, metadata/scripts.
2 Commits • 1 Features
Dec 1, 2024Month: 2024-12 — mbta/orbit monthly summary: Delivered Appcues integration and page tracking in production, including a new React component to track page views and identify users for Appcues. Also cleaned ESLint configuration by removing redundant TypeScript error suppressions across plugins, improving maintainability. Impact: enabled onboarding/engagement analytics and reduced technical debt; improved code quality and production readiness. Technologies/skills demonstrated: React, TypeScript, Appcues integration, ESLint/config management, metadata/scripts.
December 2024
Activity
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Quality Metrics
Correctness92.8%
Maintainability91.2%
Architecture88.8%
Performance86.6%
AI Usage21.4%
Skills & Technologies
Programming Languages
CSSElixirHTMLJavaScriptMarkdownSQLSVGShellTypeScriptZod
Technical Skills
API DevelopmentAPI IntegrationAccess ControlAuthenticationAuthentication and AuthorizationBackend DevelopmentBackend IntegrationCSSCode LintingComponent DesignComponent DevelopmentConfiguration ManagementContext APIData AnalysisData Fetching
Repositories Contributed To
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