Development

API and system integrations

API and system integrations connect business systems so orders, stock and other information reach the right place without repeated manual transfer. Data ownership, transfer rules and responsibilities are established first. Integrations are tested under successful and unsuccessful conditions, then handed over with understandable operating and error-handling guidance. Dev4you.lt can implement an integration within an existing system or build an intermediary system that connects several different solutions.Discuss a system integration Explore this service

SERVICE ASSESSMENT

System integration readiness diagnostic

Review data flows, contracts, failure handling and operation between existing systems. This is based on your answers, not active system or API testing.

AT A GLANCE

A clear starting point

Who it is for

Businesses seeking automated exchange of orders, stock, products or other information between systems already in use.

What we need to start

Provide system documentation, anonymised data examples, required flows and responsible supplier contacts for initial analysis.

What you receive

Receive tested data exchange, field mappings, error-handling guidance and the agreed integration handover documentation.

WHO IT IS FOR

API and system integrations: which data needs to move?

API and system integration is a defined transfer of data or actions between separate systems. A reliable solution needs more than a connection: it requires an authoritative data source, authentication, error handling, retry controls and ownership of interface changes.

An integration begins with a business flow, not simply the names of two applications. We identify the information, its origin, destination, direction and required frequency. A product description, selling price and stock quantity may have different authoritative sources. Each field needs a clear place for corrections and a rule determining which change takes precedence.

Your team provides anonymised examples, interface documentation and supplier contacts. We identify shared identifiers, status meanings and required fields. Where systems describe the same concept differently, we create a mapping. The analysis separates technical transfer work from data-quality issues that need resolving before automation can be useful.

SCOPE

When should you use an API, webhook or scheduled import?

An API provides a defined way to request information or perform an action. A webhook reports an event supported by the provider, while a scheduled import updates information at set intervals. A solution can combine these methods, such as receiving an order notification and then retrieving its details through an API.

An integration can be built without replacing the whole system. Options depend on existing interfaces, licences and provider terms.

When should you use an API, webhook or scheduled import?

The choice depends on supplier capabilities, request limits and acceptable business delay. A price list may be suitable for scheduled updates, while an order workflow may need a more immediate notification. We do not describe periodic transfers as real-time synchronisation. We also check whether the required interface is included in your existing supplier plan.

Method	Purpose	Key condition
API	Transfer of defined data or actions	Appropriate permissions, interface and provider limits
Webhook	Notification of a system event	The provider must support the required event
Scheduled import	Data updates at defined intervals	Agreed frequency and retry handling

Integration within an existing system

Where the existing system offers a suitable API, extension mechanism or other supported interface, we can implement the integration within that environment. We first check provider restrictions, available permissions and the effect of updates on custom code. This approach suits a well-defined data flow whose status and failures can be reliably monitored using the existing system’s facilities.

An intermediary system connecting several solutions

When several platforms are connected or their data structures differ substantially, we can build a separate intermediary system. It centralises field mapping, data transformation, transfer queues, error handling and retries. For example, a shop submits an order, the intermediary converts it to the format required by accounting, and the resulting status is returned to the place where the employee needs to see it.

An intermediary does not remove source-API or provider restrictions. It also needs hosting, secure access, logs and maintenance. We recommend it when clearer flow management and future extension justify an additional component. Both options are compared, with responsibility for operating each part made explicit.

How do we design reliable data exchange?

Reliability starts with understanding what happens when a transfer fails. A provider may be unavailable, restrict request volume or deliver the same event again. We therefore consider retries, queues, duplicate prevention and error states. The implementation depends on the facilities available in both connected systems.

Duplicate control is particularly important when creating orders or documents: a repeated attempt must not silently create another copy. Process risk determines when to retry and when to stop for human attention. Notifications should identify the affected flow and required action, rather than expose an unexplained technical error to the person responsible.

How are API access and transferred data managed?

An integration receives the technical permissions needed for its actions. Credentials are exchanged and stored through a separately agreed secure process; a public enquiry form is not a place for passwords or secrets. Test access is separated from production, with responsibility for validity and replacement clearly assigned.

Logs should contain enough information to diagnose an issue without copying passwords, keys or unnecessary complete personal records. Webhook authenticity is checked where the provider supports it. We also define who may inspect failures and manually retry an operation, since these actions can change real business data.

How we work

Each stage defines the work, your input and the result to check.

Analysing systems, APIs and data

We review your system documentation and representative data. You introduce the responsible suppliers, producing an account of available interfaces and constraints.

Specifying flows and responsibilities

We define direction, fields, frequency and data ownership for each flow. You confirm business rules, giving development a clear exchange specification. We choose implementation within an existing system or an intermediary layer, documenting dependencies and support needs for both options.

Developing the integration

We implement agreed connections, access controls and error handling. Your team supplies test access, and intermediate results are checked with anonymised examples.

Testing successful and failure scenarios

We test successful and unsuccessful transfers. You confirm results in the receiving system, while the record demonstrates data accuracy and retry behaviour. For an intermediary system, we also test recovery of a stopped queue and trace a record through every participant in the exchange.

Launch, monitoring and documentation

We coordinate initial reconciliation and launch. Handover includes documentation, an error-review procedure and clearly assigned supplier and client responsibilities.

How do we verify the integration’s result?

Acceptance checks the correct outcome in the receiving system, not merely whether a request was sent. Representative data is checked for field values, status and its relationship to the original record. Invalid formats, missing values, duplicate delivery and supplier downtime receive separate scenarios.

Your team confirms the business interpretation: which status indicates payment, when a document should be created and who resolves a mismatch. The test record contains the scenario, expected result and actual outcome. Before launch, we agree how existing records will be handled so the initial import does not conflict with new daily events.

What documentation and monitoring does the client receive?

Handover includes flow descriptions, field mappings, principal error states and relevant suppliers. OpenAPI can document suitable APIs, but it is not necessary for every file import. Documentation should establish ownership of the interface, credentials and version in use.

Monitoring follows business risk: who checks undelivered records, where notifications arrive and how retries are performed. Continuing response coverage and adapting to supplier changes are not automatically included in a one-off development project. These responsibilities are established before launch so the working connection has a clear ongoing owner.

Recommendations identify where transfer status is visible, who reviews alerts and how to retry safely. When an intermediary layer is used, we also document its hosting, permissions, dependencies and updates. This makes the integration understandable to the employee or administrator handling everyday issues, as well as the developer who built it.

The OpenAPI Specification provides a way to describe HTTP API operations and data schemas; the documentation scope is agreed for the interface being integrated.

Illustrative scenario: sending an order to accounting

This is an illustrative data flow. A confirmed store order must reach accounting with the agreed product code, quantity and total. If the destination is temporarily unavailable, the task remains visible for another attempt. Repeated delivery of the same order is checked against its identifier.

The acceptance outcome is one correct accounting record traceable to the original order, alongside an understandable transfer status. Controlled test data can demonstrate this. The responsible staff member can use the same status information to check everyday transfers.

Illustrative order transfer

Online storeAn approved order with an identifier, product code, quantity and amount.
Data exchangeField checks, retry control and transfer status.
Accounting systemOne correct record or a specific reason for rejection.

Online store Approved order data Data exchange

Data exchange Transfer under the receiving system’s rules Accounting system

Accounting system Acceptance or error Data exchange

A demonstration of the data flow, without claiming a particular client or provider integration.

What determines the cost?

Factor	Why it matters	Information we need
Systems and documentation	Interface capabilities and their descriptions affect development work.	System names, versions and documentation.
Flows and failure scenarios	Business rules, retries and exceptions change the scope.	Data, directions, frequency and possible failures.
Licences and support	Paid APIs and ongoing maintenance are assessed separately.	Provider plans, test environments and support needs.

FAQ

Frequently asked questions

Yes. Dev4you.lt can connect systems already in use without replacing them with one new product. We first assess interfaces, extension options and provider terms. The integration can be implemented within an existing environment or through a separate intermediary connecting several platforms. Data flows, error handling, future expansion and operational responsibility guide the choice.

Not automatically. A suitable API, import mechanism or another permitted exchange method is needed. Licences, provider rules and technical restrictions may limit the options. Mentioning a provider does not establish compatibility.

That depends on the systems and mechanism chosen. Webhooks or event interfaces may support prompt exchange, while scheduled imports run at defined intervals. Timing should be specified rather than describing every transfer as real time.

The design should include identifiers, retry recognition and exchange states. Testing covers repeated requests and interrupted connections, as well as a single successful transfer.

The specification defines whether an error is logged, a retry occurs, processing stops or a responsible person is notified. The right model depends on the importance of the data and whether repeating the transfer is safe.

Implementation may require limited technical access, but it is transferred only through an agreed secure channel. Keys, passwords and customer data should not be included in an initial public enquiry or analytics events.

Important factors include system count, documentation quality, data flows, business rules, failure scenarios and test environments. Provider licences, paid APIs and post-launch support are also assessed separately.

Handling these changes should be defined in the support agreement. Documentation records the interfaces and dependencies used so it is clear who monitors changes and how update work is assessed.

An intermediary is useful when more systems are involved, data formats must be transformed or queues, failures and retries need central management. It separates these tasks from the shop, accounting application or other main system. It is not necessary for every exchange: a simple, supported flow may only need a direct integration. We compare complexity, support needs and dependencies before choosing.

LET’S TALK

Discuss a system integration

Identify the systems, data to transfer and desired update process. We will assess interface capabilities, data ownership and verification scenarios.

Send an enquiry

API and system integrations

System integration readiness diagnostic

A clear starting point

Who it is for

What we need to start

What you receive

API and system integrations: which data needs to move?

When should you use an API, webhook or scheduled import?

Integration within an existing system

An intermediary system connecting several solutions

How we work

Can integrations be commissioned without building a new system?

Can any accounting system be integrated?

Will data be transferred in real time?

How do you prevent duplicate orders or records?

What happens if one system is temporarily unavailable?

Will we need to share API keys?

What affects integration costs?

Who maintains the integration when a provider changes its API?

When is an intermediary integration system needed?

What else may be relevant?

Discuss a system integration

Your privacy, your choice