The verdict in three sentences
To equip 40 field technicians working on mid-range Android phones with patchy coverage in basements, plant rooms and offshore sites around Singapore, an offline PWA covers most of the need: reports, photos, customer signature and deferred sync. On Kolonell's price list, this scope falls under medium-complexity custom apps, at 4,000,000-7,000,000 FCFA (6,100-10,670 EUR), for a 10 to 16 week project. A native app for Android and iOS usually costs 1.6 to 2 times more and is only justified if you need advanced hardware features or heavy background use.
The field decides the technology
A technician servicing a generator in a Jurong industrial building, a car park basement or a vessel at anchor spends part of the day with weak or no signal. The app must save the report locally, compress photos and upload everything once the connection is back. It must also run on budget handsets with limited storage, often handed out to subcontracted crews.
| Field criterion | Offline PWA | Native Android + iOS app |
|---|---|---|
| Offline mode (reports, checklists) | Yes, via service worker and local storage | Yes, simpler for large volumes |
| Before and after photos | Yes, compressed on the phone to 200-400 KB | Yes, finer camera control |
| Customer signature on screen | Yes | Yes |
| Footprint on the phone | 2 to 5 MB | 25 to 60 MB |
| Job geolocation | Yes, in the foreground | Yes, including in the background |
| Updates | Instant, no store | Through Play Store and App Store, 1 to 3 days of review |
| NFC or Bluetooth reading on equipment | Limited depending on the browser | Full |
For a standard service report (engine hours, oil level, filters replaced, parts used, photos, signature), a PWA is enough. Background geolocation or Bluetooth reading of generator controllers tips the balance towards native.
2026 cost and timeline comparison
Native figures are 2026 market estimates for an offshore or nearshore build; local Singapore agencies often quote 2 to 3 times more. The PWA line uses Kolonell's custom app price list.
| Item | Offline PWA | Native Android + iOS app |
|---|---|---|
| Development | 4,000,000-7,000,000 FCFA, about 6,100-10,670 EUR (Kolonell price list) | 6,400,000-14,000,000 FCFA, about 9,760-21,340 EUR (market estimate) |
| Timeline | 10 to 14 weeks | 12 to 16 weeks |
| Store accounts | None | Apple 99 USD a year, Google 25 USD once |
| Web back office for scheduling | Included in scope | Often priced separately |
| Monthly maintenance | 75,000 FCFA, about 110 EUR (Kolonell Standard plan) | 75,000-120,000 FCFA, two codebases |
| Rollout to 40 phones | Link plus "Add to home screen" | Store install, Apple accounts for iOS |
The real extra cost of native comes from the double codebase and store review cycles. An Android-only build narrows the gap, but supervisors on iPhones would then stay on the web back office.
What the MVP should include
A useful first release in 10 to 12 weeks includes: the day's job list pushed from scheduling, a checklist per equipment type, parts used linked to stock, photos, signature and an automatically generated PDF report sent to the customer by email or WhatsApp. The technical director's dashboard shows late jobs, maintenance contracts nearing renewal and average time per job.
Mini case study
Wei Ming, technical director of a generator maintenance firm in Singapore, manages 40 technicians. Each loses about 45 minutes a day filling in paper forms, photographing them and sending them to the office, where an assistant retypes them.
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- Time recovered with the PWA: 30 minutes per technician per day, or 40 × 0.5 × 22 = 440 hours a month.
- At a loaded hourly cost of 25 EUR, the gain reaches 11,000 EUR a month.
- With a PWA project estimated at 5,500,000 FCFA (about 8,380 EUR) plus 110 EUR of monthly maintenance, payback comes in under one month of recovered time.
Faster invoicing comes on top: signed reports go out the same day instead of 4 to 7 days with the paper circuit.
FAQ
Does a PWA really work without signal?
Yes, a well-built PWA caches the day's jobs and stores reports locally, up to several hundred MB depending on the browser. Sync happens automatically when signal returns, with a visible indicator for the technician.
How long does it take to equip 40 technicians?
Allow 10 to 14 weeks of development, then a 1 to 2 week pilot with 5 technicians. Rollout to the other 35 takes a single training day, since nothing needs to be downloaded from a store.
Can we move to native later?
Yes, if the API and back office are cleanly separated, a native app reuses 60 to 70% of the server work. Only the mobile interface needs rebuilding.
How much data does the app use?
With photos compressed to 300 KB, a technician doing 4 jobs with 5 photos each uploads about 6 MB a day. That is under 150 MB a month, well within standard data plans.
What happens if a phone is lost?
Accounts are disabled from the back office in seconds and unsynced data is encrypted on the device. Plan a replacement policy too, with a stock of 2 or 3 spare phones.
Let's scope your project. Tell us your number of technicians, equipment types and scheduling tool: we will propose an offline PWA scope within the 4,000,000-7,000,000 FCFA range and a firm timeline. Detailed quote within 48 h via our quote form. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
