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FinTech · Payments

Fintech Aggregator

One API for every payment method in Bangladesh

Client

Series-A fintech startup

Duration

10 months

Team

6 engineers, 1 SRE, 1 product designer

Year

2025

12

Payment methods

5M+

Tx / month

<100ms

p95 latency

Overview

A unified payment aggregator that lets merchants accept bKash, Nagad, Rocket, SSLCommerz, and direct bank transfers through a single REST API. Smart routing, fraud detection, automated reconciliation, and a developer-first SDK.

The Challenge

  • Every merchant in Bangladesh integrating online payments has to wire up 4–6 different SDKs (bKash, Nagad, Rocket, SSLCommerz, banks) — each with its own API quirks, downtime windows, and reconciliation format.
  • Existing aggregators were either expensive, US-focused, or didn't support all local rails.
  • Failed payments were eating 6–8% of merchant revenue due to gateway downtime and no smart routing.

Our Approach

  • Built a unified payment API in Go that abstracts every Bangladeshi rail behind one consistent interface.
  • Smart routing that detects gateway downtime in real time and re-routes transactions automatically.
  • Fraud detection layer using rule engines + ML scoring on velocity, geography, and behavioural signals.
  • Auto-reconciliation engine that matches settlements across all gateways into a single ledger.
  • Developer-first SDKs in JS, PHP, Python with sandbox + live environments.

The Outcome

  • Powering 5M+ transactions per month across 200+ merchants.
  • Reduced failed-payment rate by 73% via smart routing.
  • p95 API latency consistently under 100ms.
  • Acquired 3 enterprise clients within 6 months of launch.

What We Built

Key features
shipped to production.

Unified REST API for all rails

Smart routing & failover

Fraud detection (rules + ML)

Auto-reconciliation engine

Developer SDKs (JS, PHP, Python)

Sandbox + live environments

Webhook event system

Dashboard with real-time analytics

Tech Stack

Built with the
right tools.

GoRedisPostgreSQLKafkaKubernetesTerraform

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