Opetushallitus/koski
May 2025 – Jun 2026
14 Months active
Languages Used
JavaScriptMarkdownScalaTypeScriptHTMLJavaLessSQL
Technical Skills
API DesignAPI DevelopmentBackend DevelopmentCode RenamingData ModelingData Reporting
Juho Tammela
PROFILE
Juho Tammela
Over 14 months, contributed to Opetushallitus/koski by designing and developing robust education data services, focusing on API evolution, data integrity, and scalable reporting. Delivered features such as enhanced validation frameworks, mass data transfer APIs, and UI/UX improvements for both citizen and official views. Leveraged Scala, TypeScript, and React to implement backend data modeling, schema migrations, and frontend state management. Emphasized maintainability through comprehensive testing, documentation, and configuration management. Integrated external systems using REST and OAuth2, ensuring reliable cross-system data flows. The work consistently prioritized business value, data quality, and operational reliability, supporting complex educational workflows and regulatory compliance.
Overall Statistics
Feature vs Bugs
75%Features
Repository Contributions
333Total
Bugs
43
Commits
333
Features
130
Lines of code
2,753,869
Activity Months14
Your Network
7 peopleWork History
June 2026
14 Commits • 7 Features
Jun 1, 2026June 2026 Koski monthly review focusing on delivering business value through safer funding workflows, automated QA tooling, API usability improvements, and robust incremental loading. The period emphasized data integrity, performance optimizations, and reliability in external integrations.
14 Commits • 7 Features
Jun 1, 2026June 2026 Koski monthly review focusing on delivering business value through safer funding workflows, automated QA tooling, API usability improvements, and robust incremental loading. The period emphasized data integrity, performance optimizations, and reliability in external integrations.
June 2026
May 2026
15 Commits • 5 Features
May 1, 2026May 2026 monthly summary for Opetushallitus/koski: Delivered core Valpas enhancements, robust data loading improvements, and foundational documentation and schema work to support more reliable and scalable education data services. Focused on business value through data quality, performance, and maintainability improvements, enabling faster insights and easier developer collaboration.
May 2026
15 Commits • 5 Features
May 1, 2026May 2026 monthly summary for Opetushallitus/koski: Delivered core Valpas enhancements, robust data loading improvements, and foundational documentation and schema work to support more reliable and scalable education data services. Focused on business value through data quality, performance, and maintainability improvements, enabling faster insights and easier developer collaboration.
April 2026
32 Commits • 16 Features
Apr 1, 2026Koski – April 2026 monthly summary focusing on business value and technical achievements. Overview: - Consolidated data integrity and integration work across Ovara/OmaData in Opetushallitus/koski, with a strong emphasis on validation, data modeling, resilient data fetch, and alignment with production data. Key achievements (top 5): - Aipe validation guard and unification: prevent changes to oppimäärän suoritus type; unify and relocate Aipe validation logic; ensure shared context for oppimäärä and aineopintojen suoritus (commits bc01ae6102c5b237e76d2699bd5d614133d29890; abc5afb8e12f6eb1ddf069348db976216368b731; ccb41343e36376590d192d1c62f4e26ca73a1a88; 4044c6c0b7b82d0d4d4139ceb3bdf4dfa29b98e2). - Ovara/OmaData REST integration and data model: add REST-based fetch for valintatietojen; new data model for valintatiedoille; update Ovara GET calls and test CAS session retry for testing (commits c6ee38c396c8243cd0a92588841ef942bfd5aec1; 1ea3d16cbb5f2cde597b506121d4e7ee97b3ab0e; bca957594c25e32ca4dd9cef72e0ff5d3cace671; b87867dc58e01177f9abd30c7a119f50b7c77f2d; af163f7b9873ae040861fa8ac692afd5e8bbc9b6). - CI/testing improvements and Ovara tests: enhanced CI with new runnable test package and JSON-deserialization test for Ovara API (commits 83c952a86a27e1f24f1c656e5ca94ce5f1114dd6; 7b059c8d9026b6208440ff83916358b6726969d5). - Production data alignment and mocks: updated codes/koodistot from production and localizations; align mocks to production structures; update VST Koton mocks; rename uploader jobs for consistency (commits 32fee0fe29bccb38e61f161dd818addfd765d5ad; 8d37448fb2ffbaa3098b25818cc8883b08dc649e; 8ad51069d8f319b6928c9a22014d87e5f2bee1f0; b049c55588cd7270a023c85ab719cda60ea941e4; dd709ad16ec3eb665d895ae88872aed41c206f7b). - International school data: added iboTunniste field to international school opiskeluoikeus to improve traceability (f6acca89cd5c7a30f12382c84143558156a0954f). Impact: - Strengthened data integrity, consistent validation, and robust data ingestion across Ovara/OmaData; reduced risk of invalid study-right states and improved accuracy of reporting pipelines. - Expanded test coverage (Ovara JSON deserialization, runnable CI tests) and closer alignment of test environments with production data for reliable validation. - Enabled smoother long-term maintenance through mocks reflecting production structures and standardized naming. Technologies/skills demonstrated: - REST integration, OAuth2 / CAS session handling, error handling for service unavailability - Validation architecture and cross-domain context synchronization - Data modeling with production-aligned code lists (koodistot) - CI pipelines, test automation, and mock-driven testing - Localization management and production data synchronization - UI-related data tracking enhancements (iboTunniste field)
32 Commits • 16 Features
Apr 1, 2026Koski – April 2026 monthly summary focusing on business value and technical achievements. Overview: - Consolidated data integrity and integration work across Ovara/OmaData in Opetushallitus/koski, with a strong emphasis on validation, data modeling, resilient data fetch, and alignment with production data. Key achievements (top 5): - Aipe validation guard and unification: prevent changes to oppimäärän suoritus type; unify and relocate Aipe validation logic; ensure shared context for oppimäärä and aineopintojen suoritus (commits bc01ae6102c5b237e76d2699bd5d614133d29890; abc5afb8e12f6eb1ddf069348db976216368b731; ccb41343e36376590d192d1c62f4e26ca73a1a88; 4044c6c0b7b82d0d4d4139ceb3bdf4dfa29b98e2). - Ovara/OmaData REST integration and data model: add REST-based fetch for valintatietojen; new data model for valintatiedoille; update Ovara GET calls and test CAS session retry for testing (commits c6ee38c396c8243cd0a92588841ef942bfd5aec1; 1ea3d16cbb5f2cde597b506121d4e7ee97b3ab0e; bca957594c25e32ca4dd9cef72e0ff5d3cace671; b87867dc58e01177f9abd30c7a119f50b7c77f2d; af163f7b9873ae040861fa8ac692afd5e8bbc9b6). - CI/testing improvements and Ovara tests: enhanced CI with new runnable test package and JSON-deserialization test for Ovara API (commits 83c952a86a27e1f24f1c656e5ca94ce5f1114dd6; 7b059c8d9026b6208440ff83916358b6726969d5). - Production data alignment and mocks: updated codes/koodistot from production and localizations; align mocks to production structures; update VST Koton mocks; rename uploader jobs for consistency (commits 32fee0fe29bccb38e61f161dd818addfd765d5ad; 8d37448fb2ffbaa3098b25818cc8883b08dc649e; 8ad51069d8f319b6928c9a22014d87e5f2bee1f0; b049c55588cd7270a023c85ab719cda60ea941e4; dd709ad16ec3eb665d895ae88872aed41c206f7b). - International school data: added iboTunniste field to international school opiskeluoikeus to improve traceability (f6acca89cd5c7a30f12382c84143558156a0954f). Impact: - Strengthened data integrity, consistent validation, and robust data ingestion across Ovara/OmaData; reduced risk of invalid study-right states and improved accuracy of reporting pipelines. - Expanded test coverage (Ovara JSON deserialization, runnable CI tests) and closer alignment of test environments with production data for reliable validation. - Enabled smoother long-term maintenance through mocks reflecting production structures and standardized naming. Technologies/skills demonstrated: - REST integration, OAuth2 / CAS session handling, error handling for service unavailability - Validation architecture and cross-domain context synchronization - Data modeling with production-aligned code lists (koodistot) - CI pipelines, test automation, and mock-driven testing - Localization management and production data synchronization - UI-related data tracking enhancements (iboTunniste field)
April 2026
March 2026
19 Commits • 5 Features
Mar 1, 2026March 2026 (koski repository): Delivered cross-cutting enhancements in data integrity, master data handling, and user experience across core student rights, basic education, and reporting capabilities. Key features delivered include: 1) Basic Education: Mandatory Subjects Validation and UI – implemented mandatory flags for basic education subjects (youth and adult), UI now shows mandatory information during editing, added localized titles, refined validation by completion method, prevented duplicate student rights transfers, and expanded basic education reporting. Commit history highlights include 2fa96f64ff7c1cda8705c009f9ba926eee4c966d; fbfd7e658c3e476225f7d84995274e6af685a490; 1499629f09739e1f2db07105f411d04e1edec212; e06643d98bc2d7cdc0a16fb95b6b0c00aba1f0b6; 199b309dfef600f69b568bfb12c1008ea61ee2ca; 9f6be07204ebca61feb12d68c1cd5d1daa535a2f. 2) Master Data Linkage and ONR Integration – added support for retrieving master student identifiers from ONR for unknown opponents, enabled master-slave data linkage, and added tests for composite master-slave data retrieval to ensure correct handling of linked student data. Commits: c3fdb6bda872e0c16e5f4b57f0cb7fb58facffdf; 642abe2b99f51a3dac73785b246d50a6921c3780; 482cba811f960a058389f5d020329da00dacfa71. 3) Omadata API and Access Scopes for Student Rights – introduced Omadata package for student rights and selection data with OAuth2 scope and audit logging support, plus API enhancements (Supa API language field) and oauth scopes for omadata sample page. Commits: df147344b6c19200465f05ef664218639e46c9df; b8d2a6882c95f08a808ed5bb7d5c70880b65e579; 77d415e3967607ea801f88fa75a1585f4e514a71. 4) Valpas User Interface Improvements and Robustness – UI/UX improvements including updated localization in user view, extra contextual information, and improved routing/error handling to prevent incorrect redirects and improve user experience. Commits: 769012765d16d45b25c8c1edc59398820c27443b; ae5e51d10f201bef666545f42a0410b0fdcc72a0; 2f0728aec23b5248aa72a183577bca0e4e71a669; b924f934379d2d6f89b541a0889fa82e96f2109f. 5) Vocational Reports Updates – updated translations for vocational student year accumulation reports and aligned calculation methods effective from 2026. Commit: 91ab72cb4bf84d89d046fda8eb8186dff20422df. Major bugs fixed: Master Data Linking Search Bug Fixes – corrected master search behavior to handle scenarios where only linked slave students have study rights, ensuring master details can be retrieved by name. Commits: 87c99d2f393026d368fd1b93392b41d63eee0306; 3e3659515d6b26d5d72b7affa5437cf90dc5a9fa. Overall impact and accomplishments: Strengthened data integrity and trust in cross-system student data through robust master data linking, ONR integration, and omadata-backed rights management; improved user experience and localization in Valpas; and ensured up-to-date vocational reporting aligned with 2026 methods. These changes position the platform for smoother data governance, improved reporting accuracy, and safer, auditable data access. Technologies/skills demonstrated: ONR integration, master-slave data linkage patterns, OAuth2 scopes and audit logging (Omadata), Supa API language field enhancements, localization and UI/UX improvements, test-driven data retrieval enhancements, and robust error handling across the Valpas UX.
March 2026
19 Commits • 5 Features
Mar 1, 2026March 2026 (koski repository): Delivered cross-cutting enhancements in data integrity, master data handling, and user experience across core student rights, basic education, and reporting capabilities. Key features delivered include: 1) Basic Education: Mandatory Subjects Validation and UI – implemented mandatory flags for basic education subjects (youth and adult), UI now shows mandatory information during editing, added localized titles, refined validation by completion method, prevented duplicate student rights transfers, and expanded basic education reporting. Commit history highlights include 2fa96f64ff7c1cda8705c009f9ba926eee4c966d; fbfd7e658c3e476225f7d84995274e6af685a490; 1499629f09739e1f2db07105f411d04e1edec212; e06643d98bc2d7cdc0a16fb95b6b0c00aba1f0b6; 199b309dfef600f69b568bfb12c1008ea61ee2ca; 9f6be07204ebca61feb12d68c1cd5d1daa535a2f. 2) Master Data Linkage and ONR Integration – added support for retrieving master student identifiers from ONR for unknown opponents, enabled master-slave data linkage, and added tests for composite master-slave data retrieval to ensure correct handling of linked student data. Commits: c3fdb6bda872e0c16e5f4b57f0cb7fb58facffdf; 642abe2b99f51a3dac73785b246d50a6921c3780; 482cba811f960a058389f5d020329da00dacfa71. 3) Omadata API and Access Scopes for Student Rights – introduced Omadata package for student rights and selection data with OAuth2 scope and audit logging support, plus API enhancements (Supa API language field) and oauth scopes for omadata sample page. Commits: df147344b6c19200465f05ef664218639e46c9df; b8d2a6882c95f08a808ed5bb7d5c70880b65e579; 77d415e3967607ea801f88fa75a1585f4e514a71. 4) Valpas User Interface Improvements and Robustness – UI/UX improvements including updated localization in user view, extra contextual information, and improved routing/error handling to prevent incorrect redirects and improve user experience. Commits: 769012765d16d45b25c8c1edc59398820c27443b; ae5e51d10f201bef666545f42a0410b0fdcc72a0; 2f0728aec23b5248aa72a183577bca0e4e71a669; b924f934379d2d6f89b541a0889fa82e96f2109f. 5) Vocational Reports Updates – updated translations for vocational student year accumulation reports and aligned calculation methods effective from 2026. Commit: 91ab72cb4bf84d89d046fda8eb8186dff20422df. Major bugs fixed: Master Data Linking Search Bug Fixes – corrected master search behavior to handle scenarios where only linked slave students have study rights, ensuring master details can be retrieved by name. Commits: 87c99d2f393026d368fd1b93392b41d63eee0306; 3e3659515d6b26d5d72b7affa5437cf90dc5a9fa. Overall impact and accomplishments: Strengthened data integrity and trust in cross-system student data through robust master data linking, ONR integration, and omadata-backed rights management; improved user experience and localization in Valpas; and ensured up-to-date vocational reporting aligned with 2026 methods. These changes position the platform for smoother data governance, improved reporting accuracy, and safer, auditable data access. Technologies/skills demonstrated: ONR integration, master-slave data linkage patterns, OAuth2 scopes and audit logging (Omadata), Supa API language field enhancements, localization and UI/UX improvements, test-driven data retrieval enhancements, and robust error handling across the Valpas UX.
February 2026
12 Commits • 5 Features
Feb 1, 2026February 2026 achievements for Opetushallitus/koski focused on UI polish, data validation, and API capabilities to improve compliance, visibility, and user experience. Deliverables include UI enhancements for Special Examinations and Special Qualifications, cross-curriculum validation with test coverage, SUPA API expansion with preparatory education support and time-window filtering, UI improvements for progress and performance tables, and hiding incomplete adult basic education evaluations to reduce confusion. These changes enhance accuracy of scope and footnotes, enable precise queries, and provide consistent citizen/official views, delivering tangible value in reporting, compliance, and usability.
12 Commits • 5 Features
Feb 1, 2026February 2026 achievements for Opetushallitus/koski focused on UI polish, data validation, and API capabilities to improve compliance, visibility, and user experience. Deliverables include UI enhancements for Special Examinations and Special Qualifications, cross-curriculum validation with test coverage, SUPA API expansion with preparatory education support and time-window filtering, UI improvements for progress and performance tables, and hiding incomplete adult basic education evaluations to reduce confusion. These changes enhance accuracy of scope and footnotes, enable precise queries, and provide consistent citizen/official views, delivering tangible value in reporting, compliance, and usability.
February 2026
January 2026
35 Commits • 21 Features
Jan 1, 2026January 2026 for Opetushallitus/koski focused on expanding the SUPA API surface, tightening data integrity across Valppa interfaces, and strengthening testing and documentation. The work delivered richer study-right representations, more reliable cross-system results, and improved developer experience through better tests and docs.
January 2026
35 Commits • 21 Features
Jan 1, 2026January 2026 for Opetushallitus/koski focused on expanding the SUPA API surface, tightening data integrity across Valppa interfaces, and strengthening testing and documentation. The work delivered richer study-right representations, more reliable cross-system results, and improved developer experience through better tests and docs.
December 2025
24 Commits • 11 Features
Dec 1, 2025December 2025 (Opetushallitus/koski) delivered significant improvements to mass data transfer, data governance, and API robustness. Focus areas included enriching transfer data with geographic context, refactoring core mass transfer APIs, clarifying JSON schemas, improving error reporting, and expanding testing and documentation. These changes enhance data quality, traceability, and operational reliability across Valpas, SUPA, and OPH mass transfer workflows, enabling municipalities and educational institutions to trust and automate data exchanges with confidence.
24 Commits • 11 Features
Dec 1, 2025December 2025 (Opetushallitus/koski) delivered significant improvements to mass data transfer, data governance, and API robustness. Focus areas included enriching transfer data with geographic context, refactoring core mass transfer APIs, clarifying JSON schemas, improving error reporting, and expanding testing and documentation. These changes enhance data quality, traceability, and operational reliability across Valpas, SUPA, and OPH mass transfer workflows, enabling municipalities and educational institutions to trust and automate data exchanges with confidence.
December 2025
November 2025
38 Commits • 16 Features
Nov 1, 2025November 2025 monthly summary focusing on business value and technical achievements for Koski (Opetushallitus).
November 2025
38 Commits • 16 Features
Nov 1, 2025November 2025 monthly summary focusing on business value and technical achievements for Koski (Opetushallitus).
October 2025
44 Commits • 10 Features
Oct 1, 2025October 2025 monthly summary for Opetushallitus/koski: concise yet comprehensive delivery across validations, UI, data model, and testing. The month saw major business-value features delivered, substantial bug fixes, and improvements to reliability, maintainability, and developer productivity. Highlights include validation framework refinements with forward-looking activation dates, UI/Calendar enhancements, PreIB2019 data additions, and targeted refactoring and test stabilization.
44 Commits • 10 Features
Oct 1, 2025October 2025 monthly summary for Opetushallitus/koski: concise yet comprehensive delivery across validations, UI, data model, and testing. The month saw major business-value features delivered, substantial bug fixes, and improvements to reliability, maintainability, and developer productivity. Highlights include validation framework refinements with forward-looking activation dates, UI/Calendar enhancements, PreIB2019 data additions, and targeted refactoring and test stabilization.
October 2025
September 2025
33 Commits • 9 Features
Sep 1, 2025September 2025 Koski: Delivered multi-degree (useasta tutkinnosta) UI and data enhancements to support partial/full degree performances, adding local and common parts across multiple degrees and improving lists. Implemented frontend refactor and UI/UX enhancements (component consolidation, debounce for search, clearer naming, tighter spacing). Added degree search caching in the vocational UI and improved end-user validation messages for readability. Expanded testing coverage (UI tests for citizen view) and documentation updates (JSON schema deprecation guidance and example learners). Enforced policy changes including post-deadline transfer restrictions and vacation state validation after cutoff date to strengthen data integrity.
September 2025
33 Commits • 9 Features
Sep 1, 2025September 2025 Koski: Delivered multi-degree (useasta tutkinnosta) UI and data enhancements to support partial/full degree performances, adding local and common parts across multiple degrees and improving lists. Implemented frontend refactor and UI/UX enhancements (component consolidation, debounce for search, clearer naming, tighter spacing). Added degree search caching in the vocational UI and improved end-user validation messages for readability. Expanded testing coverage (UI tests for citizen view) and documentation updates (JSON schema deprecation guidance and example learners). Enforced policy changes including post-deadline transfer restrictions and vacation state validation after cutoff date to strengthen data integrity.
August 2025
7 Commits • 1 Features
Aug 1, 2025Concise monthly summary for August 2025 focusing on business value and technical achievements in Opetushallitus/koski.
7 Commits • 1 Features
Aug 1, 2025Concise monthly summary for August 2025 focusing on business value and technical achievements in Opetushallitus/koski.
August 2025
July 2025
6 Commits • 3 Features
Jul 1, 2025July 2025 — Opetushallitus/koski: Focused on strengthening data integrity, user control over study rights, and reporting readiness through targeted features, UI/state improvements, and API enhancements. Key outcomes include explicit removal of main-level performances, persistence improvements for EE submissions, refactored DP Core data model with UI alignment, and Migri API extension for EE sub-performance subject mapping. All changes are aligned with the updated data schema and DP Core reporting requirements, delivering tangible business value and improved developer experience.
July 2025
6 Commits • 3 Features
Jul 1, 2025July 2025 — Opetushallitus/koski: Focused on strengthening data integrity, user control over study rights, and reporting readiness through targeted features, UI/state improvements, and API enhancements. Key outcomes include explicit removal of main-level performances, persistence improvements for EE submissions, refactored DP Core data model with UI alignment, and Migri API extension for EE sub-performance subject mapping. All changes are aligned with the updated data schema and DP Core reporting requirements, delivering tangible business value and improved developer experience.
June 2025
24 Commits • 11 Features
Jun 1, 2025June 2025 performance summary for Opetushallitus/koski. This month focused on strengthening identity resolution, expanding reporting granularity for Perusopetus and Esiopetus, and improving authentication flows and test data handling to deliver higher business value and data quality. Highlights include API evolution for better data linkage, broader reporting periods and KPI data, and reliability improvements across login and data governance processes.
24 Commits • 11 Features
Jun 1, 2025June 2025 performance summary for Opetushallitus/koski. This month focused on strengthening identity resolution, expanding reporting granularity for Perusopetus and Esiopetus, and improving authentication flows and test data handling to deliver higher business value and data quality. Highlights include API evolution for better data linkage, broader reporting periods and KPI data, and reliability improvements across login and data governance processes.
June 2025
May 2025
30 Commits • 10 Features
May 1, 2025May 2025 (2025-05) focused on strengthening data integrity, production readiness, and user experience in Opetushallitus/koski. Delivered major feature work around extended duplicate validation, Sure data model integration for basic education, alignment with Koski execution context, and UI/quality improvements, while maintaining an emphasis on business value and scalable data pipelines.
May 2025
30 Commits • 10 Features
May 1, 2025May 2025 (2025-05) focused on strengthening data integrity, production readiness, and user experience in Opetushallitus/koski. Delivered major feature work around extended duplicate validation, Sure data model integration for basic education, alignment with Koski execution context, and UI/quality improvements, while maintaining an emphasis on business value and scalable data pipelines.
Activity
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Quality Metrics
Correctness92.6%
Maintainability86.4%
Architecture85.4%
Performance84.2%
AI Usage21.6%
Skills & Technologies
Programming Languages
CSSConfHOCONHTMLJSONJavaJavaScriptLESSLessMakefile
Technical Skills
API DesignAPI DevelopmentAPI DocumentationAPI IntegrationAPI designAPI developmentAPI integrationAPI testingAuthenticationBackend DevelopmentCASCI/CDCSSCSS StylingCaching
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