API & Microservices
APIs that connectthe business without breaking it.
Most integration failures are architectural, not technical — contracts were not agreed, error models were not designed, and versioning was not considered. We design the contracts first, then build the services that honour them.
What we provide
Connected systems without manual hand-offs or fragile point-to-point wiring.
- REST API design, documentation and development
- GraphQL schema design and resolver implementation
- Microservices architecture on Azure Container Apps or AKS
- Azure Service Bus and Event Grid integration
- Azure API Management — gateway, rate limiting, developer portal
- Third-party API integration (payment, logistics, CRM, ERP, messaging)
- OpenAPI / Swagger documentation and mock servers
- Legacy system bridging and anti-corruption layers
Why Theerrv
Contract before code
API contracts, error models and versioning strategy are documented as OpenAPI before a service is built — preventing breaking changes that cost weeks later.
Event-driven where it matters
We use Azure Service Bus and Event Grid for processes where decoupling and durability matter more than simplicity — not as a default, but where the architecture calls for it.
Observable from day one
Structured logging, distributed tracing and latency dashboards are built in from the first service. Failures are signals, not surprises.
Our approach
Discovery → Architecture → Development → Testing → Deployment → Support
Contract design
Endpoints, schemas, error codes and versioning strategy documented as OpenAPI or GraphQL SDL. Agreed with all consuming teams before implementation begins.
Service architecture
Service boundaries, communication patterns (sync REST vs async messaging), data ownership and failure modes decided and recorded.
Development and contract testing
Each service built and tested independently. Consumer-driven contract tests ensure integration points do not break silently.
Observability
Distributed tracing (Application Insights), structured logging, latency percentile dashboards and alert thresholds in place before production.
Deployment to Azure
Services containerised, deployed to Container Apps or AKS, behind Azure API Management — with rate limiting, auth and a developer portal.
Versioning and ongoing support
Version management, breaking-change notices with advance notice, and a maintenance agreement for the integration layer.
Technologies
The stack we use to deliver api & microservices — chosen for longevity and maintainability, not trend.
- ASP.NET Core
- GraphQL (HotChocolate)
- Azure Service Bus
- Azure Event Grid
- Azure API Management
- Docker
- Azure Container Apps
- OpenAPI 3.1
- Postman / Bruno
Industries & use cases
Fintech and Payments
- Payment gateway integration (Razorpay, Stripe, PayU)
- Financial data aggregation APIs
- Transaction notification and webhook delivery
Logistics and Supply Chain
- Carrier and 3PL integration APIs
- Real-time tracking event streams
- ERP and WMS synchronisation services
SaaS Platforms
- Multi-tenant API backends
- Webhook infrastructure and event fanout
- Partner and developer API portals
Enterprise Integration
- SAP, Dynamics and legacy ERP adapters
- CRM synchronisation and data pipelines
- Inter-department event bus and notification routing
Common questions
When should we use microservices instead of a monolith?
Microservices make sense when different parts of the system have genuinely different scaling requirements, different deployment cadences, or need to be owned by separate teams. For most early-stage products and internal tools, a well-structured monolith is faster to build, easier to debug, and cheaper to operate. We will recommend microservices only when the complexity they add is justified by the problem they solve.
What is your approach to API versioning?
We version APIs from the start, using URL-path versioning for REST (v1/v2) and schema directives for GraphQL. We maintain old versions for a defined deprecation period — communicated in advance — so consumers have time to migrate. We document breaking changes explicitly in a changelog, not in a commit message.
Can you integrate with our existing ERP or CRM system?
Yes. We have experience integrating with SAP, Microsoft Dynamics, Salesforce, Zoho CRM, Tally, and a range of Indian ERP systems. Integration typically uses the system's published API or a SFTP/EDI bridge for older platforms. We assess the integration point, agree the data contract, and build a resilient adapter with proper error handling and retry logic.
How do you handle API security?
APIs we build use OAuth 2.0 / OpenID Connect (via Azure Entra ID) or API key authentication depending on the audience. All endpoints enforce HTTPS. Sensitive data is not logged. Rate limiting and IP allow-listing are configured at the Azure API Management gateway. We conduct a security review before every API goes to production.
Related services
Start here
Tell us what theoperation is costing you.
A first conversation is a conversation, not a pitch. Describe how the work runs today and we will tell you plainly whether software is the right answer — and what it would take.
Or reach us directly at info@theerrv.com