The verdict in three sentences
For an organisation sending 60 field agents into areas with no network, an offline-first data collection app (PWA with deferred sync, geolocation and dynamic forms) costs 60,000 to 140,000 CAD built in Montreal, and 10 to 25 million FCFA excl. VAT (about 15,000 to 38,000 EUR) built by Kolonell for a team in Brazzaville, delivered in 3 to 5 months. Devices add 120,000 to 200,000 FCFA per tablet (180 to 300 EUR), i.e. 7.2 to 12 million FCFA for the fleet. Success hinges on three technical topics to price from day one: sync conflict handling, local encryption and data consumption.
What the app costs, module by module
| Module | 2026 range (FCFA excl. VAT) | Timeline |
|---|---|---|
| Form builder (conditional fields, photos, signatures) | 2,500,000 to 5,500,000 | 4 to 6 weeks |
| Offline engine and deferred sync queue | 2,500,000 to 6,000,000 | 4 to 6 weeks |
| Geolocation, GPS traces, offline maps | 1,500,000 to 4,000,000 | 3 to 4 weeks |
| Local encryption and remote device lock | 1,000,000 to 2,500,000 | 2 to 3 weeks |
| Supervision back office, dashboards, exports | 2,000,000 to 5,000,000 | 3 to 5 weeks |
| Real-condition field tests (Pool, Plateaux regions) | 500,000 to 2,000,000 | 2 to 3 weeks |
| Total project | 10,000,000 to 25,000,000 | 3 to 5 months |
The top of the range covers projects with detailed offline maps, more than 30 distinct forms or integration with an ERP or a donor database.
The technical constraints that drive the budget
| Constraint | Chosen solution | Cost impact |
|---|---|---|
| Agents offline for 3 to 10 days | local IndexedDB storage, persistent queue | included in the offline engine |
| Two agents edit the same record | timestamps, "last valid wins" rule or field-level merge, conflict log | +800,000 to 2,000,000 FCFA for advanced merge |
| Stolen or lost tablet | AES encryption of local data, remote wipe | +1,000,000 to 2,500,000 FCFA |
| Limited data plan (2 to 5 GB per month) | photos compressed to 200-400 KB, differential sync | -60 to -80% data used |
| Power cuts and battery life | power-saving mode, 20,000 mAh power bank at 15,000 FCFA | hardware |
| Beneficiaries' personal data | consent, controlled hosting, Congo Law 29-2019 (Quebec Law 25 for Canadian buyers) | 500,000 to 1,500,000 FCFA of support |
On data usage the gap is stark: a naive sync that re-uploads full-resolution photos uses 3 to 4 GB per agent per month. With compression and differential upload it drops below 800 MB, a monthly plan around 5,000 FCFA instead of 15,000 to 20,000 FCFA.
How it compares with the alternatives
| Option | 3-year cost for 60 agents (2026 order of magnitude) | Limits |
|---|---|---|
| Paper forms and re-keying | 18,000,000 FCFA of data entry and losses | 2 to 6 weeks of delay, 5 to 10% errors |
| Free tool such as KoboToolbox | 0 to 3,000,000 FCFA of setup | weak on business workflows and supervision |
| Data collection SaaS (15 to 40 USD per agent per month) | 19,000,000 to 52,000,000 FCFA | hosting outside the country, cost grows with the team |
| Kolonell custom PWA | 10,000,000 to 25,000,000 FCFA + 3,000,000 to 6,000,000 maintenance | upfront investment |
| Comparable project built in Montreal | 60,000 to 140,000 CAD, i.e. 26 to 61 million FCFA | hourly rates 3 to 4 times higher |
For a Montreal buyer running remote teams in northern Quebec or abroad, the trade-off is simple: same architecture, but Kolonell's West and Central African delivery team brings the budget down by half or more while keeping senior engineering.
Mini case study
Armel, operations director of an agricultural inputs distributor in Brazzaville, manages 60 agents visiting cooperatives in the Pool and Plateaux regions. Paper forms reach head office 3 weeks late and 8% are incomplete. He invests 16 million FCFA excl. VAT in the app and 9.6 million FCFA in 60 tablets at 160,000 FCFA.
- Re-keying eliminated: 2 data entry clerks at 250,000 FCFA per month, i.e. 6 million FCFA per year.
- Incomplete forms: 8% of 14,000 visits redone at 9,000 FCFA of travel, i.e. 10 million FCFA per year avoided.
- Faster decisions: stock reallocated in 48 h instead of 3 weeks.
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With 16 million FCFA of annual savings for 25.6 million invested, payback arrives in about 19 months, not counting the value of geolocated data for donors.
FAQ
Why a PWA rather than a native Android app?
A PWA updates without the Play Store, works offline and costs 25 to 35% less to build. Native is only justified for Bluetooth access to sensors or RFID readers.
How long can an agent stay offline?
As long as storage allows: a 64 GB tablet holds several thousand records with compressed photos. We recommend syncing at least every 7 days to limit conflicts.
Which tablets should we buy?
A 10-inch Android tablet with 4 GB of RAM and a rugged case, 120,000 to 200,000 FCFA in Brazzaville (about 250 to 400 CAD in Montreal). Avoid 2 GB RAM models, too slow for offline maps.
Where should the data be hosted?
With a replicated cloud host, or on a local server if Congo's Law 29-2019, Quebec's Law 25 or a donor requires it. Hosting costs 60,000 to 250,000 FCFA per month depending on photo volume.
What does maintenance cost?
Allow 250,000 to 500,000 FCFA (380 to 760 EUR) per month for monitoring, form updates and agent support.
Let's scope your project. Send us your agent headcount, coverage areas and current forms: we will price an offline-first PWA between 10 and 25 million FCFA (about 15,000 to 38,000 EUR) with a field test within 10 weeks. Detailed quote within 48 h. 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.