Replacing phone calls and paper logs with one operational platform
From messy operations to one clear digital system experience, an all-in-one refrigeration & AC service platform.
About Thallaja
Thallaja (ثلاجة, Arabic for “refrigerator”) brings refrigeration and AC maintenance, spare parts, rentals, installations and maintenance contracts (AMC) into one app for businesses, plus a companion app for technicians.
I designed it end to end, from research to both apps and the design system. The goal: replace a scattered process of vendors, phone calls and paperwork with one place to manage every cold-chain need.
5
services in one app
2
apps: customer and technician
100+
screens designed in Figma
1
design system behind it all
01
The challenge
The context
Cold-chain businesses run equipment that can’t afford to fail: pharma storage, restaurant cold rooms, reefer trucks. When a walk-in freezer or a warehouse AC goes down, stock and revenue disappear by the hour.
The problem
Getting it fixed meant calling around different vendors by phone or WhatsApp, with no record of what was asked, what it cost, or when anyone would arrive. Just a phone number and hope.
The brief
One platform to book, buy and track every job without chasing anyone, and a tool that keeps the technician’s side just as clear.
The stakeholders
As a designer, I kept five groups aligned through weekly reviews and demos.
Founder
Client company
Operations
Sales
Developers
Operators don’t think in services.
They think in problems.
The insight
The early plan was five separate tools. Watching operators changed that: they start from a problem, not a product category. So we built one system with five entry points, sharing the same language, components and logic.
02
Who it’s for
Two sides of the same job
Every request has two people in it: the business that needs help and the technician who shows up.
Customer app
The operator
Restaurant owners, warehouse and pharma managers, fleet operators. Busy, on the move, and usually on WhatsApp.
Book the right service fast
Know what’s happening without calling
Trust the person who walks in
Pay clearly, with a record
Technician app
The technician
Field engineers moving between sites all day, often in loud, cold, badly lit places.
04
The product
Five modules. One home.
Five services, one card each with a plain label, and anything already in motion, like an active rental, right below.
Welcome
Get started, or look around as a guest
Home
Five modules, and anything already in motion
Shop
Categories and trusted sellers up front
05
Booking a service
Four categories. One simple decision.
Air conditioning, refrigerators, cold rooms and reefers all run on the same request flow. I designed it around the hardest case, a cold room: the most equipment types, the most at stake, and often someone else at the gate. If it works there, it works everywhere.
1
Unit
→
2
Issue
→
3
Date & time
→
4
Location
→
✓
Review & pay
Step 1 of 4 · Unit
Start from the equipment
Operators may not know what’s wrong, but they know what they own.
A photo and a plain line per type, so “Blast freezer” is hard to mix up.
“From AED 99” on every row, so the price is never a surprise.
“Step 1 of 4” shows how long this will take.
Step 2 of 4 · Issue
Describe the problem in taps
Everything a technician would ask on the phone, answered with one thumb.
Urgency with a promise: Emergency shows 30 mins, Standard 3–4 hrs.
Multi-select chips for common issues, one tap to undo.
“2 issues selected” stays above Continue after the chips scroll away.
Size, brand, business type and age from lists, so the right parts get loaded.
Scroll the screen
Edge cases
Wrong unit picked
Change at the top, without losing the form.
Issue not listed
Other is always the last chip.
Several rooms on site
An optional nickname, like “Cold room 2”.
No photo to hand
Photos are optional, with a hint on what helps.
Step 3 of 4 · Date & time
Honest arrival windows
A 3-hour window a technician can keep beats an exact time they can’t.
Days start at “Today”, because a broken cold room can’t wait.
The choice is repeated above Continue.
Scroll the screen
Edge cases
Slot taken
Shown greyed as Fully booked, not hidden.
Nothing soon enough
A banner points back to Emergency.
Step 4 of 4 · Location
Get the technician to the right door
An address finds the building, not the gate or the person.
Use my location pins where the operator stands.
An on-site contact, because the person booking often isn’t the one at the gate.
Scroll the screen
Access notes like “gate 2, loading bay at the back”.
Review & pay
Confirm before you commit
Everything in one card before anything is charged.
Edit on every row, so one mistake doesn’t mean starting over.
The AED 99 fee is explained: you approve a quote before any work starts.
Scroll the screen
Cash is allowed, with a plain note about extra charges.
Processing
A calm wait that stops double taps
Booked
A booking ID, a receipt and Track service
06
Tracking
Visibility from booking to completion
Before Thallaja, knowing where a technician was meant calling someone. The tracker is one component with eight states: the same map, status, headline, technician and single action every time, so only the status changes.
When it’s going to plan
Assigning
Finding a technician
Usually 2–5 minutes
On time
On the way
Free reschedule, counting down
Nearby
Arriving in 5 minutes
A nudge to clear the gate
Arrived
Arrived
Confirm you’ve met them
When it isn’t
Delayed
Running late
Reason, new time, free reschedule
Location paused
Location lost
Last known position, marked as old
Offline
Customer offline
Calling still works
Reassigning
Technician dropped out
The booking survives
01
Never show old data as live
A stale location turns grey and says “Last seen 4 min ago”.
02
Our delay, our cost
Late arrivals name the reason, give a new time and reschedule for free.
03
Always a next step
A call button once assigned, Cancel booking before. Never a dead spinner.
From diagnosis to paid in full
Inspection report
Findings in plain words
The conclusion first: Inspection complete · quote ready.
Recommended work, numbered, matching the quote line for line.
Scroll the screen
Site photos and who inspected it, as proof.
Repair quote
A bill with nothing hidden
Pay 100%, 60% or 50% now, with the split shown.
Every line itemised, and the AED 99 fee deducted from the total.
Due now sits above the button.
Scroll the screen
Edge cases
Needs sign-off
Valid for 7 days, so the price holds.
Doesn’t want it
Decline quote sits right under Approve.
Second thoughts
The approve sheet has Not now.
Repair in progress
The record that used to be a WhatsApp thread
One line on what’s happening now.
A payments ledger: advance paid, balance due on completion.
Scroll the screen
The quote and report, one tap away for accounts.
Approve & pay
One last look
Advance paid
Paid, and what’s left
Repair complete
The balance becomes due
Paid in full
Invoice, and the job is closed
Nothing in this flow is decoration. Every element exists because cold-chain operations don’t pause for unclear updates, surprise bills or a technician nobody can reach.
07
Technician app
The other side of the job
Every status the customer sees comes from a technician action: nothing appears on one side without an action on the other.
Technician does
Customer sees
Takes the job
→
Technician assigned
Starts navigation to site
→
On the way
Enters the customer’s PIN
→
Inspection started, verified on site
Submits inspection report
→
Inspection overview with photos
Generates the estimate
→
Estimate sent, ready to approve
Completes the repair
→
Completed, invoice and rating
10
Reflection
What I learned
01
Design the handoff, not just the screens
The hardest moment isn’t on a screen. It’s a stranger walking into your cold room.
02
Design both sides together
Building both apps together kept every status honest and caught gaps early.
03
Systems let one designer scale
As a solo designer across five modules, the system was the only way to move fast without drift.
04
What’s next
Field tests for booking and tracking, then measuring booking completion, time to assign and repeat bookings.