How a BNPL marketplace unlocked 12x advertiser spend growth in 8 months

Background

Osmos built a fintech retail media program for one of India's largest Buy Now Pay Later (BNPL) platforms, used by millions by adapting an ad engine originally built for e-commerce marketplaces to a credit-led checkout instead. The platform pairs BNPL financing with its own merchant marketplace, aggregating product feeds from hundreds of independent D2C merchants and serving ads to shoppers who already carry an approved credit line.

Challenge

Monetizing a fintech checkout isn't the same problem as monetizing an e-commerce storefront, and ad infrastructure built for the latter doesn't map cleanly onto the former. For this platform, that gap showed up in three specific ways:

• Aggregator feed mechanics. Product feeds came from hundreds of independent merchants rather than one retailer's catalog, and without real-time normalization, ad spend risked going toward items that had already sold out.
• Multi-stage credit funnels. Converting a shopper into a completed EMI purchase means credit checks, down payments, and installment approval, a longer path than a normal checkout. That extra distance between an ad click and a completed, credit-approved sale created real attribution gaps.
• Multi-seller listing conflicts. High-value categories like smartphones had multiple merchants competing over the same listing, so the platform needed to know which merchant currently held the winning offer before it could safely serve an ad against that listing at all.

Solution

Osmos didn't just port over its e-commerce playbook. It rebuilt the ad engine's core logic around fintech checkout traffic, starting with catalog and listing data synced in real time so spend never landed on an out-of-stock item.

• Listing-aware ad serving. Custom eligibility logic kept ads matched to whichever merchant currently held the winning offer on a listing, with updates in under 30 minutes so ads never pointed to an outdated buy box winner.
• Credit-forward ad formats. Osmos mapped the platform's feed data to power promotional formats that lead with the installment price instead of the full price, showing an item as available from a fraction of its cost rather than the sticker price.
• A dedicated working cadence. Osmos and the platform's teams ran a joint workflow to catch schema drift and sync issues fast, closing the gap between an ad click and a completed, credit-approved sale instead of losing that connection along the way.

Impact

Since launch, the program has delivered:

• 12x growth in monthly advertiser ad spend in 8 months
• Sub-15-minute updates, keeping ads matched to live listings instead of outdated offers
• Category expansion into phones and consumer electronics, previously blocked by multi-seller listing conflicts and now the platform's highest-volume advertiser category

This became a repeatable playbook for turning BNPL checkout traffic into ad revenue, proving that D2C brands will pay a premium to reach shoppers who've already been approved for credit.