Mihály Tringel

I worked as a Power BI and Databricks Developer, delivering Power BI reporting and ETL, and developing in Databricks for an IoT solution, as well as leading a Databricks migration from an Azure SQL-based solution for one of the largest and leading European hygiene and health companies (EU).

Work included:
• Discovering existing legacy solutions and data sources
• Implementing an Azure SQL Database and Data Factory-based solution
• Planning a new Data Lakehouse-based solution using a medallion architecture
• Developing Azure Data Factory pipelines for data extraction
• Developing Databricks Catalogs and Asset Bundles in Python for ingestion and transformation
• Delivering presentations, UAT, support, and maintenance

I worked as a Power BI Developer and Data Engineer, building financial dashboards, developing ETL solutions, and implementing Supply Chain BI for one of the largest and leading European pet food companies (EU).

The work included:
• Discovering the existing legacy DWH solution and data sources
• Designing a new Data Lake-based platform using a medallion architecture
• Implementing ingestion and transformation pipelines
• Creating a unified data model for Power BI reporting
• Implementing Power BI reports for Supply Chain
• Delivering presentations and workshops, and providing UAT support

Worked on the public-facing and internal portals of Commonwealth Financial Network as a senior full-stack developer integrated into the team of front-end, back-end, and database developers, designers, testers, and managers.

I provided support for many site features, including OpenText CMS pages and ASP.NET legacy forms. I developed a React component library and React forms application to replace legacy forms. I also helped refactor, rewrite, and optimize the existing legacy codebase. I participated in code reviews and technical design decisions and mentored junior developers.

CLIENT
Commonwealth Financial Network (US)

MY ROLE
Front-end developer

TECHNOLOGIES
React, React Hook Form, React Query, TypeScript, styled-components, Storybook, ASP.NET, .NET Framework, jQuery, SQL Server

TOOLS
Azure DevOps, TFS, Git, Jira, OpenText.

Worked on the public-facing and internal portals of Elemy (former Sprout Therapy) as a senior front-end developer integrated into the international team of front-end, back-end, and database developers, designers, testers, and managers (US, Canada, Ukraine).

I implemented many site features, including several workflow solutions and a generic workflow component that separates the workflow definition, logic, and metadata from the presentation. The "Sign-up Flow" is publicly available at Elemy.com/parent-booking. I helped in the refactoring, rewriting, and optimizing of the existing legacy codebase and participated in code reviews and technical design sessions.

Client: Elemy (US)

Role: Front-end developer

Technologies: React, Redux, React Hook Form, React Query, GraphQL, TypeScript, Jest, styled-components

Tools: Spinnaker, Launch Darkly, Figma, Jira

Implemented a visual annotation tool in React to manually process camera feeds for fish farms. React Hooks, HTML5, Konva, Open CV, and React-three were used for image processing and to render 2D and 3D visualization. Rendering was optimized to avoid performance issues when working with hundreds of annotations. The tool supports pan and zoom, selection, highlighting, drag and drop, and undo/redo functionalities to work with visual elements. The Keycloak-js library was used for authentication. Integration and E2E tests were implemented using Jest/Enzyme. Back-end services were mocked for E2E tests.

Client: BioSort AS (Oslo, Norway)

Role: Front-end developer, UX designer

Technologies: React, Redux, Redux-saga, TypeScript, Material-UI, Axios, REST, HTML5, Jest/Enzyme, React-Konva, Opencv-ts, React-three

Worked on the HTML5 wizard-like user interface of a logistics application for a startup company as a front-end developer. The React SPA wizard heavily utilizes the HTML5 canvas component to provide seamless visualization and interaction when working with thousands of items (like drag-and-drop, undo/redo, zooming, selecting, highlighting, resizing, moving, rotating, and copy-pasting items).

Client: International logistics startup company (full-time remote job)

Role: Front-end developer, UX designer

Technologies: React, Redux, Redux-Saga, TypeScript, Material-UI, Axios, Rest, HTML5, Selenium, Nightwatch

Served as a front-end developer on the pixel-perfect reactive implementation of a new product's homepage and contact page for a startup company in React and TypeScript. The implementation generates eight breakpoints using SCSS to support two different layouts—mobile and desktop—from 240px to 1980px screen width and all major browsers, including IE11.

Client: A startup company

Role: Front-end developer

Technologies: React, TypeScript, Material-UI, Sass, Axios, and REST

Contributed to developing a new React-Redux single-page application as a senior full-stack developer and architect using .NET Core, React, TypeScript, and Azure. The application provided the possibility of drilling request creation for users and contained an approval workflow. It contained a complex form with many tabs and collapsible expanders; therefore, React updates and Redux-form state change optimizations were key. I migrated components from the client's non-SPA design framework to React and implemented Excel import functionality using the Open XML SDK. I implemented complex components from scratch (Typeahead, FileUpload for large attachments, formatted DMS input for geographical coordinates), cross-browser support (IE11), and a reactive user interface.

Client: One of the world's largest publicly traded international oil and gas companies (Toptal client)

Role: Full-stack developer, software architect, UX designer

Technologies: React, Redux, Redux-saga, Redux-form, TypeScript, Sass, Jest, Enzyme, .Net Core, xUnit, OpenXml SDK, REST Web API, Axios

Azure services: App Services, Active Directory (OAuth2/OIDC), SQL Server, Graph, Application Insights, Cosmos DB, DevOps, Blob Storage

Worked on a new React-Redux tenancy SPA from scratch as a front-end developer using React, Redux, and TypeScript. Scrum and CD/CI were used, and 80% of test coverage was achieved.

Client: Australian startup company (Melbourne)

Role: Front-end developer

Technologies: React, Redux, Redux-saga, Redux-form, TypeScript, Material-UI, Axios, Jest, and Enzyme

Helped with the migration of a single-page web app from JavaScript to TypeScript, enriching the codebase with models and typed services. Migrated around 300 files in 1.5MB within four weeks with minimal errors. I also provided technical expertise to the offshore team.

Client: Australian startup company (Melbourne)

Role: Front-end developer, TypeScript expert

Technologies: ASP.NET MVC Razor, custom SPA framework, Framework7, TypeScript, and jQuery

A mobile-targeted web application (SPA/PWA) for field workers to assess work safety conditions and processes using their devices. The job includes back-end development, mobile UX development, CSS animations, and HTML5 image processing camera pictures.

CLIENT
XTO Energy (Toptal client)

ROLE
Full-stack developer

TECHNOLOGIES
Blazor WebAssembly, Blazor Fluxor, Sass, CSS animations, HTML5, TypeScript, .NET Core

Azure services: Active Directory (OAuth 2/OIDC, B2C), App Service, Blob storage, Cosmos DB, Application Insights, Google Analytics, DevOps, Azure AD B2C

The purpose of the application is to process images sent by Edge devices to Azure Functions using Azure's Custom Vision API. Tagged images are saved in Azure Blob storage, while meta-data is saved into a Cosmos DB. Users can view the camera feeds in a streaming player or by individual images. Events and email/SMS notifications are generated based on user subscriptions and user profile preferences. Active Directory authentication and role-based authorization are used. Managed service identities are used to connect to resources. All keys are stored in Azure Key Vault.

ROLE
Full-stack developer

CLIENT
One of the world's largest publicly traded international oil and gas companies (Toptal client).

TECHNOLOGIES
Angular 7, RxJs, NgRx/store, NgRx/effects, Ngx-bootstrap components, Sass, Chart.js, Jasmine, Karma, .NET Core, xUnit.net

AZURE SERVICES
Active Directory (OAuth 2/OIDC), App Service, WebJobs, Functions, Blob Storage, Cosmos DB, Key Vault, Custom Vision, DevOps

The purpose of the system is to facilitate the preparation of the KIC business plans and budgets by clarifying the requirements in terms of structure, content, level of detail, and categories of information; the nature and scope of information to be provided for KIC added value activities; and KIC complementary activities.

The SharePoint OOB user interface has been replaced with a custom-developed UI which satisfied usability requirements for structured input of meta-data, in-place editing for multiple rows simultaneously, easy input of budget line hierarchy, validation of in-place edited meta-data on-the-fly, on-the-fly evaluation of formulas for cost tables during structured input, easy selection, and multiple selections during in-place editing of referenced items.

Client: European Institute of Innovation and Technology (Grape Solutions' client)

Role: Full-stack developer and software architect

Technologies: Angular 4, TypeScript, RxJS, Bootstrap, .Net, SharePoint 2013, and SQL Server

Contributed to an Azure MVC Razor architecture pilot implementation, creating Azure AD users and subscriptions programmatically for end-users after successfully approving a workflow. The project contains unit tests with silent login, dashboards (Application Insights telemetry), and a single-click deployment package (Azure PowerShell).

Client: One of the world's largest publicly traded international oil and gas companies. (Toptal client)

Role: Full-stack developer and software architect

Technologies: ASP.NET Core MVC Razor, jQuery, Bootstrap, .Net Core

Azure services: App Services, Active Directory (OAuth 2/OIDC), SQL Server, AD Graph, Graph, Application Insights, and PowerShell

Advisory Planning is used by the client’s advisers and agencies for their detailed annual income and strength planning and reporting. The implemented spreadsheet component calculates the formulas on the fly and can be used from any popular web browser. The calculation engine also supports the backward propagation of modified summary values. The solution has a layered and distributed architecture with the front end deployed into the DMZ and the back end put behind the firewall accessible through web services.

I replaced the previous Excel-based FPA solution used by 3000+.

Client: Hungarian branch of Generali Group (Grape Solutions' client)

Role: Technical team lead and software architect

Technologies: ASP.NET, Html, CSS, jQuery, SQL Server, SSRS, and Web Services.

Worked on the unique and innovative in-house test automation framework software pilot of the company for the currently unsupported technical stack using Selenium WebDriver and Appium WebDriver.

Client: Testifi GmbH (Munich, Germany)

Role: Full-stack developer

Technologies: .Net Core, Selenium, Appium, Selenium WebDriver API, XPath, PdfSharp

CAS is used by customs officers and travelers worldwide at many exit points at different airports (Singapore, Finland, Jordan) for supporting the VAT refund process for tax-free shopping.

The SOA-based system identifies travelers by credit cards, passports, or bar codes on invoices, and validates the bought products for a VAT refund. The approval transaction is digitally stamped by customs.

The system contains a very complicated and comprehensive rules-based validation engine for country-dependent legal validation, black/white list validation, and random rejection for which parameters can be scheduled depending on the time of the day. The system complies with very strict performance and security measurements (PCI-DSS, PKI, transport-level security).

Client: Global Blue (Grape Solutions' client)

Role: Technical team lead, software architect, project manager

Technologies: WPF, WCF, MSMQ, SQL Server, PCI-DSS, Smartcard/PKI, SOA

Owned the migration of a Power BI solution to Tableau using Azure SQL Database and Data Factory. I designed and implemented staging and DWH databases (data mart) and ETL processes. Additionally, I deployed the Tableau Server into Azure and configured Azure Active Directory SAML single sign-on. I also implemented the ETL process using the Azure Data Factory and logic apps for SFTP files.

CLIENT
Healthcare startup company in Massachusetts (Toptal client)

MY ROLE
BI developer

TECHNOLOGIES
Power BI, Tableau, SQL Server, Azure Virtual Machines, Azure Active Directory, SAML single sign-on, Azure Data Factory, and Azure Logic Apps

The goal of the EIT BI project was to integrate all data from the previous projects and custom data from numerous Excel spreadsheets into a single data warehouse and analytical database to provide self-service functionalities for the users for the whole authoring process from data extraction, analysis, aggregation, and custom expression calculation to data model building. The project also included data cleansing and sanitization tasks.

Client: European Institute of Innovation and Technology (Grape Solutions' client)

Role: Technical team lead and project manager

Technologies: SQL Server, SSAS MOLAP, SSIS, Excel, Power Pivot, Power Query, Power View, and SharePoint Excel Services.

Led the analysis, design, and implementation of a Microsoft BI product initially developed for the Uzsoki Hospital, which provides monitoring capabilities on a daily basis for the top management of the institution.

Using such a rapidly loaded monitoring tool, the hospital achieved a 2 – 4% cost savings on its budget.

The solution is based on SQL Server BI and Excel dashboards to provide users with eye-catching dashboards with slicers, drill-down capabilities, geospatial visualization, and self-service BI functionalities, not only for the presentation of the data but for the whole authoring process, including extraction, analysis, aggregation, custom expression calculation, and data model building.

CLIENT
Uzsoki Hospital (Grape Solutions' client)

MY ROLE
Technical team lead, software architect, and project manager

TECHNOLOGIES
SQL Server, SSAS MOLAP, SSIS, Excel, Power Pivot, Power Query, and Power View.