Microservices and API development: change one part without breaking the rest

Large applications get slow to change because every update touches everything. We split them into smaller services with clear APIs, one piece at a time, build new cloud-native services from the start, and put secure, documented APIs around the systems you keep, so your applications can grow without a rewrite.

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What we cover

What microservices areSmall services, each with one job and a clear interface
When it fitsNot every application needs microservices
ModernizationFrom one large system to parts you can change safely
API developmentAPIs built for real-world data
Cloud-nativeServices that scale and recover on their own
IntegrationConnecting services to the systems you keep

What microservices are

Small services, each with one job and a clear interface

Microservices are an architectural style in which an application is built as a set of small, loosely coupled services, each organized around one business capability, such as orders, pricing, invoicing or notifications. Each service has its own clearly defined interface, its own data and its own release cycle, and talks to the others through APIs or events.

The benefit is independence. A team can change, test and deploy one service without touching the rest, scale the busy parts without scaling everything, and replace a piece that no longer fits.

When it fits

Not every application needs microservices

Microservices add moving parts: more deployments, more monitoring and more network calls that can fail. They pay off when an application is large, changes often, is worked on by several teams, or has parts with very different loads. For a small application, a well-structured single code base is simpler and cheaper to run, and we will recommend one. Many of our projects end up in between: a modular core, with separate services where independence matters most.

Modernization

From one large system to parts you can change safely

We rarely recommend rewriting a working system in one go. Instead, we review the architecture, agree a roadmap and move one capability at a time: put an API in front of the old system, build the new service behind it, move the traffic over and retire the old code. The business keeps running on the existing system while the new one grows around it, and every step can be tested and reversed.

What we do

Architecture review and modernization roadmap
Monolith to microservices, step by step
APIs around legacy functions
Automated testing before every release

API development

APIs built for real-world data

An API is a contract that other teams and partners build on. We design REST and GraphQL APIs around the business rather than the database tables, document them with OpenAPI so others can use them without a meeting, and version them so a change never breaks an existing client. Every API checks who is calling and what they may do, validates what it receives, and handles slow or failing dependencies with retries, queues and clear errors.

What we do

REST and GraphQL API design
OpenAPI documentation
Authentication, authorization and rate limits
Versioning that keeps existing clients working

Cloud-native

Services that scale and recover on their own

We build services to run in containers and serverless functions on Azure and AWS: each one scales with its own demand, restarts on its own when it fails, and reaches other services and databases through managed identities rather than stored passwords. For a national food cooperative, we moved the document processing behind a label comparison agent from Copilot Studio to Azure Functions when it outgrew the low-code platform.

What we do

Containers and serverless functions on Azure and AWS
Managed identity instead of stored passwords
Automated build and deployment pipelines
Monitoring and tracing across services

Integration

Connecting services to the systems you keep

Services rarely live alone: they need customers from the CRM, orders from the ERP and stock from the warehouse system. We connect them through APIs and events, map and validate the data between systems, and document every data flow. For the same cooperative, a workflow keeps customer records, approvals, order history and profile changes in step across the online store, the CRM, the ERP and the marketing platform. Our systems integration practice covers this side in depth.

Case studies

Microservices and APIs in practice

Client names are withheld. We are happy to share details on a call.

All case studies

Delivered
Every change, flagged
Food manufacturing
Application Software Development
Label comparison agent for a national food cooperative
Compares two versions of a product label, highlights every change, annotates the PDF and returns an audit-ready list of differences. We moved it from Copilot Studio to Azure Functions when the document processing outgrew the low-code platform.
- Audit-ready differences in one chat turn
- Rebuilt from low-code to cloud functions
Read the case study →
In delivery
4 systems, 1 record
Food manufacturing
Application Software Development
One customer record across four business systems for a national food cooperative
Wholesale customers sign up in the online store, are approved in the CRM, copied to the ERP and marketed to from a separate platform, and changes made by phone reached none of the others. The workflow keeps customer records, approvals, order history and profile changes in step across all four, and flags anything that needs a person.
- Four systems, one customer record
- Exceptions routed to a named reviewer
Read the case study →

Questions

Common questions

What is the difference between microservices and APIs?

Microservices are a way of structuring an application as small, independent services. APIs are the interfaces those services, and any other system, use to talk to each other. You can have APIs without microservices: we often put an API in front of an existing system so new applications can use it.

Do we have to rewrite our application to use microservices?

No. We move one capability at a time behind an API while the existing system keeps running. Many applications never need to be split completely; we stop when the parts that change most are independent.

Are microservices more expensive to run?

They can be, because there are more parts to deploy and monitor. That is why we recommend them only where the independence pays off, and automate deployment and monitoring from the start.

How do you keep APIs secure?

Every call is authenticated and authorized, inputs are validated, traffic is encrypted and rate-limited, and services reach each other through managed identities instead of stored passwords. We also keep an inventory of every API, so none is forgotten.

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