Modernizing Legacy Integrations with a Serverless Middleware Platform
Sagar Panwar
Bridging 20+ Year Old Systems With Modern Digital Services
The Challenge
Many government departments still rely on legacy SOAP-based systems built decades ago. As newer services moved to JSON APIs, teams struggled to make both worlds communicate.
The existing approach required custom integrations for every service, causing:
- High development and maintenance costs
- Frequent failures due to format mismatches
- Limited visibility when something went wrong
- Security risks when exposing legacy systems directly
The goal was clear: Create a secure, scalable, centrally managed service that translates SOAP ā JSON effortlessly.
Our Solution
We built a fully serverless, event-driven middleware platform on AWS that acts as a smart translator between old and new systems.
It performs three key functions:
1. Translate SOAP to JSON Automatically
Incoming SOAP requests are processed by AWS Lambda functions that:
- Parse XML structures
- Convert them into clean JSON payloads
- Pass them to modern systems
- Transform JSON responses back into SOAP
This eliminated the need for every team to build their own converters.
2. Fully Secure & Private Communication
Government data cannot travel over public networks.
So we designed the platform with multiple layers of security:
- Private API Gateway accessible only inside a controlled VPC
- AWS WAF IP allow-listing for approved systems
- Route 53 inbound resolver to securely route traffic from legacy internal networks
- Isolated environments: dev ā int ā pre-prod ā prod
This ensured government systems communicate safely and predictably.
3. Operational Visibility for All Teams
To avoid blind spots, we integrated:
- CloudWatch logging for every request
- Dashboard widgets showing:
- Number of calls per service
- Error spikes
- Latency metrics
Operational teams can now monitor everything from a single dashboard.
How We Contributed
Our role was to architect and implement the complete AWS setup using Infrastructure-as-Code (IaC):
Platform Engineering
- Designed CDK stacks for Lambda, API Gateway (private), VPC integration, and DynamoDB
- Built DynamoDB schemas for templates, certificates, and request metadata
- Designed IAM roles, permissions, and API Gateway authorizers
Security Engineering
- Implemented WAF rules for IP whitelisting
- Configured Route 53 inbound resolver
- Ensured secure VPC connectivity for legacy clients
DevOps & Automation
- Created CI/CD pipelines (Code Pipeline + Code Build) for multi-environment deployments
- Automated testing, synthesizing, and deploying CDK stacks
- Reduced deployment time from hours to minutes
The Impact
ā Enabled seamless integration between legacy and modern systems
ā Reduced custom integration effort by 70%
ā Improved operational visibility with unified dashboards
ā Eliminated security risks from public API exposure
ā Centralized templates and metadata in DynamoDB for consistency
This solution is now the backbone for many inter-department communications in the platform.