Quantifying Lost Users from Failed OTPs
Every undelivered verification code is a user who cannot complete their intended action. For registration flows, this means a permanently lost signup. For login flows, this means a frustrated user who may never return. For transaction confirmations, this means lost revenue. The impact compounds across millions of verification attempts.
Our analysis of anonymized data across thousands of customers reveals that the average user who fails to receive a verification code on the first attempt has only a 37 percent chance of retrying. After a second failure, that drops to 8 percent. By the third attempt, the user is effectively lost. Each percentage point of delivery rate directly corresponds to retained users and completed actions.
For a mid-sized SaaS company processing 100,000 verifications per month, a delivery rate of 97 percent versus 99.9 percent means approximately 2,900 failed deliveries. With a 37 percent retry rate and typical conversion values, this translates to roughly 1,800 lost user actions per month, a figure that adds up to significant revenue impact over a year.
Conversion Funnel Impact
Verification sits at the most critical point in the conversion funnel: the moment when a user has already decided to act and is waiting for permission to proceed. Unlike other funnel stages where users drop off due to lack of interest or competing priorities, verification failures lose users who are actively engaged and ready to convert.
A/B tests across our customer base consistently show that improving SMS delivery rate has a larger impact on overall funnel conversion than almost any other single optimization. A 1 percent improvement in delivery rate typically yields a 0.8 to 1.2 percent improvement in end-to-end conversion, depending on the product category and flow design.
The funnel impact is particularly pronounced in markets with less reliable telecommunications infrastructure, where delivery rates from lower-quality providers can dip below 90 percent. For companies expanding into emerging markets in Africa, South Asia, and Southeast Asia, verification delivery rate often becomes the single largest factor in regional conversion performance.
Cost Per Failed Delivery
The cost of a failed OTP delivery extends far beyond the direct cost of the undelivered message. Consider the full cost chain: the user acquisition cost that brought the user to the point of verification, the engineering and support resources consumed by retry attempts and failure investigations, and the lifetime value of the user who was lost.
For a consumer fintech application with a customer acquisition cost of 25 dollars and an average lifetime value of 400 dollars, each user lost to a failed verification represents a 425-dollar loss: the wasted acquisition spend plus the unrealized lifetime value. At scale, even small improvements in delivery rate translate to enormous value preservation.
There are also hidden costs that rarely appear in financial models: brand reputation damage from users who share their frustration on social media, increased support ticket volume from users seeking help with failed verifications, and the engineering time spent investigating and working around delivery issues rather than building new features.
How Delivery Rate Improvements Directly Boost Revenue
We worked with an e-commerce platform that was experiencing a 96.2 percent SMS delivery rate with their previous provider. After migrating to TrueCheck, their delivery rate improved to 99.7 percent. Over the following quarter, they attributed an 11 percent increase in completed checkouts to the improved verification flow, representing over 3 million dollars in additional revenue.
A ride-sharing company in Southeast Asia saw similar results. Their driver onboarding flow required phone verification, and failed deliveries were causing a 15 percent drop-off at the verification step. After switching to our multi-carrier routing architecture, the drop-off fell to 2 percent, dramatically accelerating their driver supply growth in a competitive market.
The mathematics are straightforward but often overlooked: verification is a multiplicative step in the conversion funnel. Every percentage point of delivery improvement multiplies through every downstream conversion step. This makes verification delivery rate one of the highest-leverage optimization points available to product and growth teams.
Optimization Strategies
The most impactful optimization is selecting a verification provider with genuinely high delivery rates backed by transparent, real-time reporting. Marketing claims of 99 percent delivery are meaningless without the data to back them up. Demand access to per-country delivery metrics and hold your provider accountable to specific SLAs.
On the product side, implementing intelligent retry logic can recover a significant portion of failed deliveries. A second attempt via an alternate route, triggered automatically after a configurable timeout, catches many transient carrier issues. Offering users the option to receive their code via voice call as a fallback further reduces loss from SMS delivery failures.
Finally, monitor your delivery funnel end-to-end, from API call to code entry. Track not just delivery rates but also time-to-delivery, code expiry rates, and user retry behavior. These metrics together paint a complete picture of your verification health and reveal optimization opportunities that delivery rate alone cannot surface.
Investing in verification infrastructure may not be as exciting as building new features, but the ROI is often orders of magnitude higher. A one-time integration improvement that adds two percentage points to your delivery rate will generate returns every single day, compounding across every user who verifies through your system.