Company Name
Financial Services
500+ Employees
United States

Flex – Calculation Engine

Flex – Calculation Engine is a SaaS product powered by AWS that is driven by AWS Serverless technologies to deliver, scale, and secure product lifecycle. The calculation engine guarantees penny-accurate calculations at all stages of the contract life cycle.

  1. Lack of scalability in infrastructure
  2. Manual deployment
  1. Use of AWS Managed services to increase Security, Scalability and High Availability
  2. Enabled one click deployment to automate infrastructure provisioning
  1. Performance improvement with reduced latency
  2.  Staff productivity through automation of infrastructure
New Services Added
  1. AWS Lambda
  2. Amazon API Gateway
  3. Amazon ElastiCache

Problem Statement

Flex – Calculation Engine is a newly launched product that required utilization of AWS payasyougo model by leveraging Serverless Architecture followed by best practices. During assessment, improvement areas identified are Infrastructure Automation, Application Deployment, Scalability and High Availability. Securing API Gateway and AWS CloudFront against web attacks was one of the critical requirements.

Proposed Solution Architecture

Flex calculation engine makes use of the AWS Managed services including Route53, Lambda, CloudFront, S3, SES, and RDS. Route53 receives requests and after identifying the request type routes it to CloudFront for Web Based Request and API Gateway for API request. API Gateway handles the REST APIs requests and route it to associated service provided by Lambda Functions. Enable one click deployment to automate infrastructure provisioning along with CI/CD Pipeline for Application Deployment. AWS WAF ensures the security of the API Gateway and AWS CloudFront. 


By using API Gateway REST Regional and Private endpoints with resource-based policies, NETSOL Technologies was able to achieve the required functionality. NETSOL used API Gateway private integrations to use NLB, as well as exposed private endpoints to certain VPCs by whitelisting them via resource-based policies.

Outcomes of Project & Success Metrics

AWS Managed Services were used to successfully develop and launch SaaS application. With AWS Serverless services, all functional and non-functional requirements were met. Seamless API integration with API Gateway and Lambda functions. Oneclick deployment ensured automated infrastructure deployment and provisioning. AWS WAF was used to protect the API Gateway and AWS CloudFront from web attacks.

  • AWS Lambda
  • Amazon API Gateway
  • Amazon Aurora PostgreSQL
  • AWS X-Ray
  • Amazon ElastiCache
  • Amazon CloudWatch
  • Amazon S3
  • Amazon inspector

Below is the TCO Calculator link:

Lesson Learned

  1. ElastiCache with RDS offloaded read requests and improved performance.