Webhook delivery, retries, and replay
Relay Webhook Delivery
Signed webhook delivery with a PostgreSQL queue, automatic retries, and manual replay. A dashboard shows every attempt and the path back from failure.
Full stack engineer
I like knowing how the whole feature works.
I’m Petar. I work at Zühlke on software for retail stores, mostly TypeScript, React, Node.js and .NET on Azure, plus Kotlin on Android for store notifications.
Professional work
What I build at work.
Some of what I’ve built at Zühlke. The full list is on the About page and in my resume.
Zühlke
Belgrade, Serbia
Software EngineerFeb 2024 to Present- Designed and built Azure Durable Functions batch processing with per delivery retries and a poison queue; used Cosmos DB ETags and retries to prevent concurrent updates from silently overwriting store data.
- Proposed and built Azure Web PubSub updates replacing polling every 60 seconds, so store staff see delivery changes without waiting up to a minute.
- Built core features for a Next.js store operations PWA: navigation, notes, tasks, deliveries, feature flags and offline access to previously loaded data.
BlueGrid
Belgrade, Serbia
Frontend DeveloperMay 2021 to Sep 2023OMP
Barcelona, Spain · Remote
Frontend DeveloperOct 2020 to Mar 2021
Side projects
Projects I’ve worked on.
Relay handles webhook delivery, Batch validates CSV imports, and Smart Office covers desk and parking bookings. These case studies explain the implementation and choices behind each project.
CSV import, validation, and review
Batch Transaction Processor
Upload a CSV, see which rows are wrong and why, then confirm only the valid ones. Tested with files up to 10,000 rows.
Desk and parking reservations
Smart Office
I worked on a hackathon prototype for booking desks and parking spaces, checking in on arrival, and automatically releasing unused reservations.