Mads Hærup

Payroll software used daily by accountants and payroll administrators across the Nordics. A Vue 3 single-page app in TypeScript, served by an AWS backend through services generated from OpenAPI specifications.

• AG Grid views over payroll datasets large enough that row virtualisation, and keeping derived values out of the render path, decide whether the screen stays usable.
• Replaced nested lookups with keyed maps on a list that grew with every payroll run, turning a scan that squared with the data into a single pass.
• Parallel loading with Promise.all so independent requests stop queueing behind each other.
• Tests in Vitest and Testing Library, end to end in Cypress, delivered through Bitbucket Pipelines.

• Vue 3
• TypeScript
• Pinia
• AG Grid
• SCSS
• Vitest
• Cypress
• AWS

• azets.dk →

SAP's public API portal, where developers browse and test the APIs behind SAP's products. Built in Angular and TypeScript, with RxJS driving search, filtering and the catalogue views, against a catalogue large enough that the listing had to stay responsive while filters changed.

• Angular
• TypeScript
• RxJS
• SCSS
• Jenkins

• api.sap.com →

Extended the SAP UI5 library with custom React components used by other teams inside SAP. Strict TypeScript conventions, documented states, and every component checked against WCAG with axe and keyboard testing before it was released to the other teams.

• Worked from Figma with the designers, pushing back where a pattern would not hold up for keyboard or screen reader users.
• Kept the public API of each component narrow so consuming teams could upgrade without rewrites.

• React
• TypeScript
• SAP UI5
• Storybook
• WCAG
• ARIA
• axe

• SAP UI5 →

A Next.js application pulling ranked results from Apache Solr alongside a graph database queried with SPARQL, so a search returned both matching documents and the entities related to them. Result sets ran long enough that the lists were virtualised and the queries were kept off the render path.

• Next.js
• React
• TypeScript
• Apache Solr
• SPARQL
• FastAPI

E-commerce front ends built in JavaScript, Liquid and SCSS: product filters, discount rules and cart flows, measured on conversion and on how quickly the storefront became usable on a phone over mobile data.

• JavaScript
• Liquid
• SCSS
• Tailwind
• Responsive

• grafikr.dk →

A meta-framework on Preact, Bun and Nitro using islands architecture: a page ships server-rendered HTML and hydrates only the components that have to be interactive, so the JavaScript sent to the browser scales with the interactive parts rather than the page. Written to understand rendering, hydration and routing from the inside.

• Preact
• Bun
• Nitro
• TypeScript
• SSR
• Islands

• npmjs.com/org/useavalon →

A harness for coding agents: a turn loop built on Strands, evaluation suites, Langfuse tracing, MCP integrations and a skill format written in Markdown. Ask, plan and agent modes decide what the agent is allowed to do, with shell execution and commits held behind an explicit approval. Ships as a terminal interface, a desktop app and a library.

• TypeScript
• Strands
• MCP
• Langfuse
• Evals
• Bedrock

• github.com/useAvalon/caelence-agent →