Jan Mikoláš
Receiving data
An import or event from an external service
- Authentication and validation
- Pagination or batch retrieval
- Idempotent processing
- Persisting state and outcome
Back to skills
Experience
API and integrations
I do not see an API integration as a few endpoints. It is a reliable flow of data between systems — from the business requirement through failure states to operational traceability.
Integrations need to work beyond the ideal scenario.
In e-commerce, I have worked on marketplace integrations, order imports and exports, and inventory synchronisation. The first successful run is not enough; duplicates, service outages, and delayed responses also need a safe outcome.
That is why I build integrations around an explicit contract, secure authentication, pagination and external-service limits, and a way to trace and resolve problems without corrupting data.
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What I address in an integration
From the business process to operational oversight.
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Business flow
Marketplaces, orders, and inventory
First I need to understand which data is the source of truth and what exactly the synchronisation is meant to change. This matters for orders, inventory availability, product data, and marketplace connections. -
API contract
A clear and documented interface
I use REST interfaces and OpenAPI documentation as an agreement between systems. I address data structures, validation, versioning where it makes sense, and secure authentication to external services. -
Reliability
Handling the reality of external services
External APIs have limits, outages, and sometimes return the same event more than once. I therefore account for pagination, rate limiting, idempotency, retries, and unambiguous error capture. -
Operations
Traceable synchronisations
An unsuccessful synchronisation must not disappear without a trace. It needs to be possible to identify its state, diagnose the cause, and safely resume processing without duplicates or corrupted data.
Flow design
A reliable integration has clear steps and responsibilities.
I choose the concrete shape according to the system and data volume. The principle remains the same: validate input, process the change safely, record its state, and keep repeating it under control.
Not every integration needs a queue or a complex mechanism. I choose the degree of resilience according to the impact of failure, data volume, and external-service capabilities.
Calling an external API
A safe export or synchronisation
- A prepared API contract
- Respecting service limits
- Retries and failure states
- Logging and monitoring
I use in integrations
Technologies around APIs and data flows
- REST API
- OpenAPI / Swagger
- OAuth 2.0 / OIDC
- JWT
- RabbitMQ
- Redis
- PostgreSQL
- Symfony Console
Need to connect systems without fragile synchronisations?
I can design a new API or review an existing integration flow — from the business process to reliable operations.