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Thomas Gran

PROFILE

Thomas Gran

Over 21 months, contributed to opentripplanner/OpenTripPlanner by engineering core routing, data ingestion, and real-time planning features. Focused on backend development and API modernization, they refactored the routing stack for safer extension, improved transfer and pass-through logic, and enhanced observability with robust logging and debugging tools. Leveraging Java and Python, they introduced modular data models, streamlined CSV parsing, and enabled real-time updates through interfaces like TripCalendars. Their work emphasized maintainability, test coverage, and code clarity, with targeted bug fixes and documentation updates that improved reliability, performance, and developer experience across complex transit and routing scenarios in production environments.

Overall Statistics

Feature vs Bugs

80%Features

Repository Contributions

795Total
Bugs
73
Commits
795
Features
297
Lines of code
3,668,816
Activity Months21

Your Network

56 people

Work History

June 2026

6 Commits • 4 Features

Jun 1, 2026

June 2026 — OpenTripPlanner (opentripplanner/OpenTripPlanner) delivered stability, observability, and data-model enhancements that strengthen reliability, performance, and readiness for real-time planning features. Key changes include elevating TransitGroupPriority to a stable feature, reducing log noise and improving logging performance for timetable updates, relaxing data constraints to improve null handling, and enabling serialization for DefaultTripCalendars to support persistence and safe real-time updates.

May 2026

61 Commits • 36 Features

May 1, 2026

Month: 2026-05 Overview: This month focused on delivering high-value features, hardening path correctness for pass-through and via scenarios, and strengthening the platform's observability and real-time data capabilities. The work emphasizes business value through more accurate routing results, safer API surfaces, and improved developer experience for future iterations. 1) Key features delivered - SpeedTest data model enhancements and results updates: Rename cost and add c2 and duration fields to results, plus updates to SpeedTest results to reflect the richer metrics. (Commits: 4b3929895f0d7f5a741d2a11928280ab3df81665; db8ff53633680fee3de0330ec4bf1e18e9144775) - Pass-through and via handling improvements: Correction of board position for pass-through connections at the correct stop and proper forwarding of transit arrivals to the next segment for pass-through via, preventing invalid transfer sequences. (Commits: 7b078667be562719f3bd7cb366db5b514ffad8b4; cd0b1d19e01ef9c6b910a983a9cd37a36c88dcc0; 4fc9586d9e453714a001c9a96f86ac38e3b3f598) - Per-worker correctness for transits: Moved transitsForRoundComplete from a lifecycle event to per-worker RaptorWorkerState, fixing cost accounting for pass-through scenarios. (Commit: 3f06f265003a112d1d4829287f995ae20aad149c) - TripCalendars interface and real-time updates: Introduced TripCalendars to replace CalendarService and enable real-time updates, with injection into TimetableSnapshot for real-time consistency. (Commits: 3afa43e2ad55fd7a26473e0c7c2142116e0eb543; 60c3a40940a34d1a9b3728772ca952ea5830fdd9) - Debug/observability improvements: Added --debug-request flag to OTPMain to enable request logging for manual and monkey testing. (Commit: 56484706ccb69a056e40707b525ed7852682ef6e) 2) Major bugs fixed - Board pass-through connections at correct stop; fix to avoid mis-timed boarding/alighting during pass-through transfers. (Commit: 7b078667be562719f3bd7cb366db5b514ffad8b4) - Forward transit arrivals to the next segment only for transit-based pass-through via paths; avoids forwarding non-transit arrivals and incorrect costs. (Commit: cd0b1d19e01ef9c6b910a983a9cd37a36c88dcc0) - Prevent consecutive transfer legs from walk arrivals forwarded at via connections; ensures PathBuilder consistency. (Commit: 4fc9586d9e453714a001c9a96f86ac38e3b3f598) - SpeedTest CSV parser capitalization/logic issues fixed to ensure robust parsing. (Commit: d74399af8d3b9cd33dc2ddb8af4eb16db92063f3) - TripStopTimeTest adjusted for stop-position boundary constraints to reflect new limitations (cannot alight at origin, cannot board at last stop). (Commit: a675b2917d4680fadddbb113a326f2fc8ceb37ca) 3) Overall impact and accomplishments - Increased routing correctness and reliability for pass-through commodities, reducing invalid path artifacts and improving user trust in itinerary results. - Improved analytics capability and decision support through richer SpeedTest metrics. - Strengthened architectural foundations for real-time updates and future data-flow enhancements with TripCalendars and TimetableSnapshot integration. - Enhanced observability with a CLI flag for request-level logging, boosting debugging efficiency in manual testing scenarios. - Performance and maintainability gains from targeted refactors and per-worker correctness improvements, setting the stage for parallelized area computations and caching strategies. 4) Technologies/skills demonstrated - Java/Kotlin-like refactoring discipline, domain-driven structuring, and API safety improvements (sealed modifiers, interface evolution). - Data modeling and result-tracking enhancements for measurable business value. - Performance-oriented optimizations and correctness hardening for transit routing logic. - Observability, debugging, and troubleshooting enablement (debug-request flag). - Real-time data flow integration and caching considerations (TripCalendars, TimetableSnapshot integration).

April 2026

70 Commits • 25 Features

Apr 1, 2026

Month 2026-04: Delivered a modernization of the Raptor-based routing stack in OpenTripPlanner, with a Core Raptor refactor that replaces C2-based pass-through with via-connection chaining, reduces dead code, and simplifies internal flows for safer future changes. Reorganized repository structure to improve maintainability by moving Stop/Arrival/Ride classes into dedicated packages, sealed McStopArrival, and clarifying responsibilities. Introduced API renames and documentation improvements across ViaConnection, ArrivalParetoSetComparatorFactory, PatternRide/AbstractPatternRide, and related components, along with a broad set of tests and documentation updates. Boosted performance and reliability with SpeedTest warm-up improvements and targeted test enhancements, and centralized Pareto/dominance logic to simplify future optimization. Business value: faster builds, clearer APIs, more predictable routing behavior, and reduced maintenance risk.

March 2026

67 Commits • 23 Features

Mar 1, 2026

March 2026 OpenTripPlanner monthly summary highlighting stability, performance, and maintainability improvements across core routing and transfer features. Delivered targeted correctness fixes, large-scale refactors for safer extension and configurability, and expanded testing/observability to support faster delivery cycles and higher confidence in routing results.

February 2026

7 Commits • 1 Features

Feb 1, 2026

February 2026 (OpenTripPlanner) monthly summary: Delivered targeted transit-delay handling improvements and algorithm refactors to boost reliability and performance, plus corrections to DST-related tests and public metadata. The work enhances real-time routing accuracy, maintainability, and test coverage, directly supporting better service planning and user experience.

January 2026

27 Commits • 10 Features

Jan 1, 2026

January 2026 (2026-01) OpenTripPlanner: Delivered core routing enhancements, reliability improvements, and maintainability gains that support faster feature delivery and a higher-quality user experience. Highlights include Raptor heuristics enhancement with direct transit search, strengthened test infrastructure, comprehensive documentation updates, and configuration/API hygiene improvements. Also resolved critical DST/multiday trip handling in the departure board and implemented validation cleanup to reduce runtime issues.

December 2025

34 Commits • 16 Features

Dec 1, 2025

Month: 2025-12 monthly summary for opentripplanner/OpenTripPlanner. The month focused on delivering key routing features, stabilizing the build, enhancing debugging capabilities, and improving test coverage. Major business value was realized through API clarity, data accuracy, and developer experience improvements.

November 2025

63 Commits • 28 Features

Nov 1, 2025

November 2025 delivered a set of focused improvements to the OpenTripPlanner transfer generation and graph-building stack, driving reliability, performance, and real-time data integration. The work emphasizes business value for live routing scenarios, maintainability, and readiness for upcoming via-location features.

October 2025

26 Commits • 8 Features

Oct 1, 2025

October 2025 OpenTripPlanner monthly summary focusing on API modernization, reliability, and developer velocity. Delivered a broad refactor to adopt withX builders across core builders (FareAttributeBuilder, AStarBuilder, TransitPreferences.Builder, DebugRequestBuilder, JourneyRequestBuilder, TransitRequestBuilder) to enable fluent construction and safer defaults. Refactored EncodedPolyline: moved to o.o.api.model.geometry, removed Serializable, added lazy initialization, renamed encode() to of(), and exposed distance calculations in GraphQL. Renamed TripDelaysDto to TripDelaysAgregator across the codebase for clarity. Documentation updates added CLAUDE.md, Empirical Delay Sandbox docs, and a PR rejection template. Fixed release workflow: checked bump.ser.ver.id in custom-release.py and switched changelog to use next-version-tag. Addressed code quality from reviews (requireNonNull, replace withX, fixed empiricalDelay typos).

September 2025

31 Commits • 9 Features

Sep 1, 2025

2025-09 monthly summary for opentripplanner/OpenTripPlanner: focused delivery of the Empirical Delay initiative, reinforced by CSV ingestion, robust parsing, testing support, and stability improvements. Demonstrated strong end-to-end delivery, API integration, and code quality enhancements with tangible business value for transit delay analysis and planning.

August 2025

18 Commits • 4 Features

Aug 1, 2025

Summary for 2025-08: The OpenTripPlanner team delivered foundational improvements in data ingestion, observability, and release processes, strengthening reliability and business value across the platform.

July 2025

3 Commits • 2 Features

Jul 1, 2025

July 2025 monthly summary for OpenTripPlanner focusing on test infrastructure improvements for street mode linking and tightening stop-to-street linking constraints. Delivered more robust test coverage, improved data realism, and enforced a 100m linkage constraint to increase routing accuracy, contributing to safer deployments and reduced regression risk.

June 2025

37 Commits • 8 Features

Jun 1, 2025

June 2025 highlights for OpenTripPlanner: Delivered a robust PR handling and Git integration refactor that aligns versioning (latest/next) and PR metadata with GitHub data, facilitating reliable PR-to-release workflows. Strengthened release processes with PR existence checks and improved version resolution logic, reducing release risk and turnaround time. Fixed a serialization bug to ensure PR metadata is accurately stored and consumed by downstream tooling. Improved developer experience with documentation cleanups and custom-release-extension UX enhancements, including clearer output and adherence to code-review guidance. Expanded test coverage and code quality across transit mode mappings and request/mapper components, including unit tests for SelectRequestMapper and TransitFilter mappers, reinforcing reliability and maintainability.

May 2025

49 Commits • 20 Features

May 1, 2025

May 2025 focused on API modernization, reliability, and data-import enhancements for OpenTripPlanner. Key work included enabling CAR transfers with ferries during NeTEx import, extending emissions support to handle negative CO2 values, and sweeping refactors to standardize request objects and builders across Transit/Route APIs, improving safety, consistency, and maintainability. Additional investments in logging, documentation, code quality, and targeted bug fixes enhanced stability and data correctness across the project.

April 2025

77 Commits • 24 Features

Apr 1, 2025

2025-04 monthly summary for opentripplanner/OpenTripPlanner. Delivered a major refactor aligning emissions-related code under a single emission namespace, significantly improving maintainability and onboarding. Implemented per-leg emission data and exposed emissions through the Transmodel API, unlocking granular carbon insights for route planning and customer-facing dashboards. Strengthened data reliability with improved emission data I/O (datasource injection, per-datasource progress logging) and updated tests and documentation to reflect the emission-domain model. Addressed critical reliability issues and quality improvements through targeted bug fixes and test refinements.

March 2025

84 Commits • 34 Features

Mar 1, 2025

March 2025 performance summary for opentripplanner/OpenTripPlanner focused on core refactors that strengthen stability, scalability, and business value. Key outcomes include immutable itinerary modeling, unified cost handling, broader adoption of ItineraryBuilder, enhanced test coverage, and release-readiness improvements. The changes lay the groundwork for safer concurrency, easier feature integration, and more predictable planning results while maintaining a strong emphasis on code quality and maintainability.

February 2025

55 Commits • 23 Features

Feb 1, 2025

February 2025 contributions focused on strengthening path accuracy, API robustness, and build/test maintainability for OpenTripPlanner. Key work centered on feature delivery that enhances user-facing routing quality, plus targeted bug fixes that improve reliability and stability. The effort also advanced the project’s maintainability through refactors, improved testing infrastructure, and build configuration improvements, aligning with longer-term performance and scalability goals for complex transit queries.

January 2025

16 Commits • 2 Features

Jan 1, 2025

January 2025 monthly summary for opentripplanner/OpenTripPlanner: Delivered feature-rich API customization, improved data integrity, and reinforced CI practices, enabling stronger product offering and reliability. Key outcomes include profile-based Transmodel API documentation with GraphQL injection, coordinate-based transfers in itinerary mapping, fixes for bookWhen null, non-null StreetLeg.walkSteps, and UTF-8 property file handling.

December 2024

12 Commits • 5 Features

Dec 1, 2024

December 2024 monthly summary for opentripplanner/OpenTripPlanner focusing on delivering business value through schema accessibility, packaging modernization, routing consistency, and build-data improvements, complemented by release automation and code quality enhancements.

November 2024

38 Commits • 11 Features

Nov 1, 2024

November 2024 accomplishments focused on stabilizing and modernizing the Raptor-based testing stack, aligning test coverage with current OpenTripPlanner features, and implementing packaging and observability improvements to shorten release cycles and reduce risk. Key work included modernization of the Raptor test framework with reusable components, cleanup of outdated tests, and improvements to test data models and request mapping. In addition, OTP feature validation, shading packaging, and Maven POM cleanup streamlined deployments. Minor fixes to Siri URL handling and improved startup/shutdown logging/docs enhanced reliability and developer experience.

October 2024

14 Commits • 4 Features

Oct 1, 2024

October 2024: Key architectural improvements, test stability, and feature clarity delivered for OpenTripPlanner. Focused on modularization and data model generalization, while ensuring transfer generation robustness and up-to-date documentation. Notable outcomes include CI performance test stabilization, codebase restructuring to OTP_UTILS, generalization of vehicleType, inclusion of empty rail stops in transfers, and updated Sorlandsbanen feature docs.

Activity

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Quality Metrics

Correctness94.8%
Maintainability94.2%
Architecture92.6%
Performance89.0%
AI Usage20.8%

Skills & Technologies

Programming Languages

BashGraphQLGroovyJSONJavaJavaScriptMarkdownPropertiesPythonSQL

Technical Skills

AI IntegrationAPI DesignAPI DevelopmentAPI DocumentationAPI IntegrationAPI designAPI developmentAlgorithm DesignAlgorithm OptimizationArchitectureBackend DevelopmentBug FixingBuild AutomationBuild ConfigurationBuild Management

Repositories Contributed To

1 repo

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

opentripplanner/OpenTripPlanner

Oct 2024 Jun 2026
21 Months active

Languages Used

JavaMarkdownYAMLShellXMLGraphQLPythonProperties

Technical Skills

ArchitectureBackend DevelopmentBuild System ManagementCI/CDCode CleanupCode Organization