Tharun Kumar

The problem

Which state-management approach to reach for is usually argued in the abstract. I wanted the comparison grounded in one real app, where the feature set is identical and only the state layer changes.

What I built

• Implemented boards, lists, cards, checklists and drag-and-drop against the official Trello API, with real-time sync and persistent cloud storage.
• Rebuilt the same app on four branches — plain React state, Context API, Redux Toolkit, and Redux Toolkit in TypeScript — each a complete working implementation rather than a sketch.
• Typed the store, actions and API responses in the TypeScript branch to see what the type layer actually catches once the app is non-trivial.

Outcome

Four deployable branches over one API, and a first-hand read on where Context stops scaling and where Redux Toolkit starts paying for itself.

The problem

A certificate is only worth what a third party can verify. Issuing PDFs by email gives a recipient no way to prove a document is genuine, unexpired and not revoked.

What I built

• Built the issuance flow: upload a PDF, image or DOC, position a QR stamp, flatten the stamp into the document and store it with metadata.
• Made verification public and stateless — anyone with a credential ID or the QR code can check validity and see a preview, no account needed.
• Layered JWT auth with role-based access over it: admins issue, stamp and revoke; users manage only their own documents.
• Added expiry and revocation so an issued certificate can be invalidated after the fact.

Outcome

Full issue → stamp → verify → revoke lifecycle, with an admin invitation system for onboarding new issuers.

The problem

Fuel fills, odometer readings and vehicle assignments were tracked on paper, which made reconciliation and escalations slow and unreliable.

What I built

• Built a driver-facing React app for fills, odometer readings and daily schedules, designed for phone use in the field.
• Built a separate supervisor console over the same data for vehicles, escalations and reconciliation.
• Shared one Express REST backend across both — auth, fills, vehicles, odometer, schedule, escalations and health routes.

Outcome

Three deployed apps sharing a single API surface: sendotracker, vehicle-app and superviser-app.