The verdict in three sentences
Card fraud is fought with 3DS2, mobile money fraud with OTP and velocity checks: at checkout, the two mechanisms stack. In Nairobi in 2026, enabling 3DS2 cuts card fraud by 60 to 80% at the cost of 2 to 5 abandonment points, while mobile money stays under 0.1% fraud thanks to PIN and OTP. The goal is not to block everything, but to balance security and conversion.
Anti-fraud rules that work and their conversion cost
A good anti-fraud policy stacks simple, measurable rules rather than an opaque engine. Here are the most cost-effective rules and their impact on conversion.
| Rule | Fraud effect | Conversion cost | Priority |
|---|---|---|---|
| 3DS2 on every card | -60 to -80% | -2 to -5 pts | High |
| OTP on mobile money | Fraud < 0.1% | ~0 pt | High |
| Block after 3 PIN failures | Anti brute-force | ~0 pt | High |
| Cap per IP / 24h | Anti carding | -0 to -1 pt | Medium |
| Velocity check (n tx / hour) | Anti automation | -0 to -1 pt | Medium |
| Device scoring / fingerprint | Detects multi-accounts | -1 pt | Medium |
| Email/number blacklist | Repeat offenders blocked | ~0 pt | Low |
The winning combo in Nairobi: mandatory 3DS2 on cards + OTP on mobile money + block after 3 PIN failures. That is 80% of the result for near-zero conversion impact on mobile money.
The real cost of unblocked fraud
Unblocked card fraud costs more than the stolen amount: there is the lost product, dispute fees and processing time. Let us compare for an average basket of 40,000 FCFA.
| Cost item | Without anti-fraud | With 3DS2 + OTP |
|---|---|---|
| Avg fraudulent amount / month | 120,000 FCFA | 25,000 FCFA |
| Dispute fees (5 to 15k / case) | 30,000 FCFA | 5,000 FCFA |
| Lost merchandise | Yes | Rare |
| Support time | High | Low |
| Added cart abandonment | 0 | 2 to 5 pts |
On an average volume, moving to 3DS2 + OTP often saves over 100,000 FCFA per month in fraud and fees, far above the few abandonment points conceded.
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Mini case study
Fatou runs an online fashion shop in Nairobi, 6,000,000 FCFA collected per month, 25% by card. Before, she suffered about 0.8% card fraud, i.e. 12,000 FCFA stolen per month plus 30,000 FCFA of disputes. By enabling 3DS2, card fraud drops to 0.2%, she loses 2 points of card conversion but saves nearly 35,000 FCFA net per month. On mobile money (75% of volume), OTP keeps fraud under 0.1% without touching conversion.
FAQ
Does 3DS2 really scare customers away? It costs 2 to 5 abandonment points depending on banks, but that cost is largely offset by the 60 to 80% drop in card fraud and the liability shift to the issuer.
Does mobile money need anti-fraud? PIN and OTP already keep fraud under 0.1%; you mainly add a block after 3 failures and a velocity check to cut automated attempts.
What is a velocity check? It is a rule limiting the number of payment attempts per IP, card or account over a period, to block carding and scripts without bothering a normal customer.
How much does unblocked fraud cost? Beyond the stolen amount, count 5,000 to 15,000 FCFA of dispute fees per case plus lost merchandise: a single fraud can wipe out the margin of several orders.
Can I disable 3DS2 to improve conversion? It is risky: without 3DS2 fraud liability returns to the merchant and disputes become nearly unwinnable; better to refine the rules than remove authentication.
Let's talk about your project. We calibrate your 3DS2 and OTP anti-fraud rules to maximize security without breaking conversion. 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.
