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Stefan Berthold

PROFILE

Stefan Berthold

Over seven months, contributed to the wireapp/wire-server repository by delivering eight features and resolving three bugs focused on backend reliability, security, and governance. Work included refining API schema definitions using OpenAPI, enhancing authentication flows with SAML and AWS integrations, and improving configuration management through CODEOWNERS consolidation and RabbitMQ admin host standardization. Leveraged Go, Haskell, and YAML to implement robust error handling for AWS S3 uploads, personalize onboarding emails, and enforce protocol correctness in distributed systems. Emphasized operational safety with rollback strategies and test coverage, while aligning code ownership to accelerate reviews and clarify responsibilities across engineering and operations teams.

Overall Statistics

Feature vs Bugs

73%Features

Repository Contributions

14Total
Bugs
3
Commits
14
Features
8
Lines of code
1,993
Activity Months7

Work History

September 2025

1 Commits • 1 Features

Sep 1, 2025

September 2025 focused on API schema accuracy and improved client compatibility for wire-server. Delivered a targeted OpenAPI refinement for the Pict type and aligned older API versions with the updated schema, reducing integration ambiguity and enabling more reliable client code generation and validation.

May 2025

3 Commits • 1 Features

May 1, 2025

May 2025 monthly summary: Delivered critical reliability and operational improvements in wire-server. Key work includes a robustness fix for SAML authentication parsing, and the initial rollout of adminHost configuration for RabbitMQ service definitions. These efforts improve authentication reliability, standardize access to RabbitMQ management interfaces, and enhance safety with rollback capabilities. The work involved dependency updates, UTF-8 handling improvements in the hxt library, and service definition changes with accompanying tests and change-management practice.

April 2025

1 Commits • 1 Features

Apr 1, 2025

April 2025: Landscape alignment and ownership governance improvements in wire-server repo. Consolidated CODEOWNERS to explicitly include platform engineering and customer operations for changelog, charts, and docs directories, while preserving root ownership with the backend team. This reduces review bottlenecks, clarifies responsibilities, and accelerates changelog/documentation changes.

March 2025

1 Commits

Mar 1, 2025

March 2025 monthly summary for wireapp/wire-server: Addressed a critical error-path for interrupted AWS S3 uploads by correcting error classification and adding test coverage, thereby reducing false alerts and improving client-facing feedback. The change strengthens upload reliability and monitoring accuracy with minimal risk to existing functionality.

February 2025

2 Commits • 1 Features

Feb 1, 2025

February 2025: Delivered governance improvements for wire-server by introducing CODEOWNERS to define ownership and strengthen code review accountability. Updated ownership to include @wireapp/backend for charts/ and changelog.d/ directories, complementing existing @wireapp/platform-engineering ownership. Implemented via two commits: 1a33896bd68a994b4fef9669ea25ace1d9815ab4 (create CODEOWNERS file) and 38fa7213952e43b28ac1887d9ff0b9ce815686ff (Add backend team to all subdirs in CODEOWNERS). No major bugs fixed this month. Impact: clearer ownership, faster PR reviews, improved traceability, and stronger collaboration across frontend/backend teams. Tech: Git, CODEOWNERS, repository governance, cross-team coordination.

January 2025

4 Commits • 2 Features

Jan 1, 2025

January 2025 monthly summary for wire-server team focusing on security, reliability, and protocol correctness. Implemented TLS for Cassandra connections, enhanced bot routing authentication boundaries, and fixed MLS protocol ordering to ensure consistent client state. Updated tests and changelog to reflect these improvements and to support future secure deployments.

December 2024

2 Commits • 2 Features

Dec 1, 2024

December 2024: Wire Server delivered two value-driving features with direct business impact and clear technical ownership. 1) Team Owner Welcome Email Personalization: included the profile name in the new owner welcome email, removed the unused PersonalUserMemberWelcomeEmailTemplate, and updated the sendNewTeamOwnerWelcomeEmail flow to inject profileName. 2) MLS Cipher Suite Configuration and API Parameterization: updated the default MLS cipher suite and required the cipher suite as a query parameter on key-package endpoints, removing hard-coded defaults (with potential breaking changes for MLS clients). No major bugs documented for this period. The changes collectively improve onboarding personalization, security posture, and API configurability, while signaling effort for client migration where applicable.

Activity

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Quality Metrics

Correctness88.6%
Maintainability87.2%
Architecture87.2%
Performance77.2%
AI Usage20.0%

Skills & Technologies

Programming Languages

GoHaskellNginx configurationTypeScriptYAML

Technical Skills

API DesignAPI DevelopmentAPI Gateway ConfigurationAWS IntegrationAuthenticationBackend DevelopmentCode OwnershipCode Ownership ManagementConfiguration ManagementDevOpsDistributed SystemsEmail TemplatingError HandlingHaskellHelm

Repositories Contributed To

1 repo

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

wireapp/wire-server

Dec 2024 Sep 2025
7 Months active

Languages Used

HaskellYAMLGoNginx configurationTypeScript

Technical Skills

API DevelopmentBackend DevelopmentConfiguration ManagementEmail TemplatingProtocol ImplementationAPI Gateway Configuration