hmrc/property-business-api
Dec 2025 – Jan 2026
2 Months active
Languages Used
Scala
Technical Skills
API developmentScalaback end developmentbackend developmentfunctional programmingsoftware development
Marcy Calderon
PROFILE
Marcy Calderon
Over six months, this developer enhanced HMRC’s tax APIs and data pipelines, focusing on reliability and maintainability. They delivered features in Scala across repositories such as hmrc/property-business-api and hmrc/individuals-capital-gains-income-api, implementing robust validation logic, refining data mapping, and clarifying schema definitions. Their work included end-to-end migration flows for property business submissions, simplification of API call paths, and improvements to input validation in the self-employment API. By standardizing schema design and strengthening test coverage, they reduced technical debt and improved data integrity, enabling more accurate downstream reporting and easier future maintenance for CSV and JSON-driven backend systems.
Overall Statistics
Feature vs Bugs
86%Features
Repository Contributions
10Total
Bugs
1
Commits
10
Features
6
Lines of code
9,432
Activity Months6
Your Network
4 peopleShared Repositories
4
Work History
June 2026
1 Commits
Jun 1, 2026June 2026 monthly summary for the hmrc/self-employment-business-api workstream, focusing on data integrity and input validation for Building Details.
1 Commits
Jun 1, 2026June 2026 monthly summary for the hmrc/self-employment-business-api workstream, focusing on data integrity and input validation for Building Details.
June 2026
April 2026
1 Commits • 1 Features
Apr 1, 2026April 2026 monthly summary for hmrc/individuals-capital-gains-income-api. Delivered a feature to simplify Capital Gains Tax API calls by removing conditional feature switch checks across URIs, improving downstream call paths, maintainability, and reducing future complexity.
April 2026
1 Commits • 1 Features
Apr 1, 2026April 2026 monthly summary for hmrc/individuals-capital-gains-income-api. Delivered a feature to simplify Capital Gains Tax API calls by removing conditional feature switch checks across URIs, improving downstream call paths, maintainability, and reducing future complexity.
March 2026
1 Commits • 1 Features
Mar 1, 2026March 2026 monthly summary for hmrc/individuals-capital-gains-income-api: Key focus on clarifying capital gains tax definitions within the API schema to improve data contracts and business clarity. Delivered Capital Gains Tax Definitions Clarification by updating schema descriptions to better reflect the purpose and context of tax allowances. This change reduces downstream interpretation errors, speeds integration with downstream services, and strengthens alignment with tax policy language. Commits associated: MTDSA-33438 Update descriptions (42061c72d3ceba7d2ab8f84e7503ac6bf88aa00d).
1 Commits • 1 Features
Mar 1, 2026March 2026 monthly summary for hmrc/individuals-capital-gains-income-api: Key focus on clarifying capital gains tax definitions within the API schema to improve data contracts and business clarity. Delivered Capital Gains Tax Definitions Clarification by updating schema descriptions to better reflect the purpose and context of tax allowances. This change reduces downstream interpretation errors, speeds integration with downstream services, and strengthens alignment with tax policy language. Commits associated: MTDSA-33438 Update descriptions (42061c72d3ceba7d2ab8f84e7503ac6bf88aa00d).
March 2026
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026 focused on delivering the HIP Migration API for UK Property Business Annual Submissions (Create and Amend) in hmrc/property-business-api. Implemented end-to-end migration flow with validation and robust error handling across multiple scenarios, enabling automated annual submissions and improving data integrity. This work reduces manual rework and supports regulatory reporting readiness.
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026 focused on delivering the HIP Migration API for UK Property Business Annual Submissions (Create and Amend) in hmrc/property-business-api. Implemented end-to-end migration flow with validation and robust error handling across multiple scenarios, enabling automated annual submissions and improving data integrity. This work reduces manual rework and supports regulatory reporting readiness.
December 2025
5 Commits • 2 Features
Dec 1, 2025December 2025 monthly summary for two repositories: hmrc/property-business-api and hmrc/individuals-capital-gains-income-api. Focused on delivering API enhancements, simplifying surfaces, and strengthening test coverage to boost reliability and speed of value delivery for downstream consumers.
5 Commits • 2 Features
Dec 1, 2025December 2025 monthly summary for two repositories: hmrc/property-business-api and hmrc/individuals-capital-gains-income-api. Focused on delivering API enhancements, simplifying surfaces, and strengthening test coverage to boost reliability and speed of value delivery for downstream consumers.
December 2025
October 2025
1 Commits • 1 Features
Oct 1, 2025Month: 2025-10. Focused on refining employment income data mapping to improve downstream data handling and reporting accuracy. Delivered a configuration change in the hmrc/income-tax-mtd-changelog repository that updates sa100_mapping_v2.csv to adjust the action for 'Individuals Employment Income' from 'Amend a Custom Employment' to 'Create and Amend Employment Financial Details'. This change is tracked under commit 3bcc5a618226629939c763e95c698be7b47933fb and lays groundwork for more precise categorization and downstream data routing.
October 2025
1 Commits • 1 Features
Oct 1, 2025Month: 2025-10. Focused on refining employment income data mapping to improve downstream data handling and reporting accuracy. Delivered a configuration change in the hmrc/income-tax-mtd-changelog repository that updates sa100_mapping_v2.csv to adjust the action for 'Individuals Employment Income' from 'Amend a Custom Employment' to 'Create and Amend Employment Financial Details'. This change is tracked under commit 3bcc5a618226629939c763e95c698be7b47933fb and lays groundwork for more precise categorization and downstream data routing.
Activity
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Quality Metrics
Correctness90.0%
Maintainability88.0%
Architecture88.0%
Performance88.0%
AI Usage28.0%
Skills & Technologies
Programming Languages
CSVJSONScala
Technical Skills
API DevelopmentAPI developmentData MappingScalaSchema Designback end developmentbackend developmentfunctional programmingsoftware developmenttestingvalidation logic
Repositories Contributed To
Overview of all repositories you've contributed to across your timeline
hmrc/individuals-capital-gains-income-api
Dec 2025 – Apr 2026
3 Months active
Languages Used
ScalaJSON
Technical Skills
API developmentScalabackend developmentAPI DevelopmentSchema Design
hmrc/income-tax-mtd-changelog
Oct 2025 – Oct 2025
1 Month active
Languages Used
CSV
Technical Skills
Data Mapping
hmrc/self-employment-business-api
Jun 2026 – Jun 2026
1 Month active
Languages Used
Scala
Technical Skills
Scalabackend developmentvalidation logic