In many SMEs, the issue is not a lack of tools. It is that each tool only solves one part of the work. The ERP manages stock and accounting, the ecommerce platform sells, the CRM tracks opportunities, logistics confirms shipments and teams end up copying data from one screen to another. At first this can look efficient, but over time operational debt appears: repeated tasks, hard-to-trace incidents and decisions based on data that no longer matches.

Integration should not be a project to “connect everything”, but a way to reduce manual work and define who owns each piece of data.

The real symptom: not missing software, missing rules

When a company says it “needs to integrate systems”, it is worth starting with the concrete operational pain. Sometimes the issue is orders being entered twice. Sometimes it is a customer created in several places with different details. In other cases, stock updates arrive too late and cause overselling. The common mistake is to try to solve this with more technology before clarifying which system is the source of truth for each type of information.

Integration should not be seen as a bulk copy between applications, but as an architecture of responsibilities. One system may be the master for product data, another for pricing, another for invoicing and another for customer service. If that hierarchy is not defined, every sync introduces ambiguity. And when there is ambiguity, teams end up correcting things manually, which is exactly what integration was supposed to avoid.

Before discussing APIs, queues or middleware, it is worth documenting four things: where each piece of data is created, which system is the source, when updates happen and what should occur in case of conflict. It is less flashy than a technical demo, but it saves many problems later.

What to integrate first, and what to leave for later

Not every process deserves the same level of automation. A common mistake is to integrate, from day one, flows with high variability and low volume while leaving for later the flows that consume most of the team’s time. Priority should be based on operational impact.

In practice, these usually make sense first:

• Orders from ecommerce into the ERP to avoid manual re-entry.
• Available stock from ERP or WMS into the store to reduce overselling.
• Customers and addresses to avoid duplicates across sales, billing and support.
• Invoices, delivery notes or shipment statuses so backoffice teams do not have to chase information.
• Catalogs or prices when there is a clear approval process.

By contrast, it is wise to be cautious with integrations that depend on many human judgments or frequent commercial exceptions. For example, if every order needs a different manual validation, automating everything from the start may hide the real problem instead of solving it. Sometimes the best integration is a semi-automated flow with human review at the critical points.

A good rule is to start with what is repetitive, stable and measurable. If the flow changes every week, the process needs to be organized first; only then should it be integrated.

Designing integrations to be maintainable

Many integrations fail not at launch, but in maintenance. When volume is low, everything seems fine. But as soon as fields, providers or business rules change, the solution becomes fragile and any adjustment touches too many parts.

To avoid that, a few simple principles help:

1. Separate integration from business logic

The integration layer should not contain complex decisions that belong to the process itself. Its job is to move data, transform only what is necessary and record events. If logic is spread across scripts, connectors and hidden rules, it becomes very hard to audit why something happened.

2. Log events and errors in a readable way

It is not enough for a message to “fail”. You need to know which data failed, when, in which system and what response came back. If a team needs technical help to understand every incident, the integration is not operable. Good design leaves traces that are useful for support and for the business.

3. Plan for retries and incomplete cases

Real integrations do not live in a lab. There are occasional outages, timeouts, malformed data and duplicates. Instead of assuming perfection, the system must be able to retry, isolate errors and recover an operation without replaying the entire process.

4. Design for future change

An ERP may change, an online store may expand to another country and a provider may be replaced. If everything is tightly bound to a single connector, every change becomes a mini migration. Designing with clear contracts and decoupling points reduces that risk.

How to choose between API, middleware or custom integration

There is no universal answer. The best choice depends on volume, criticality, change frequency and how much control the company needs.

A direct API can be enough when the process is simple and the two systems are well defined. Middleware or an iPaaS can add value when there are several systems, repeated transformations or the need for centralized monitoring. A custom integration can be the best option when the operation has strong specificities, complex rules or very specific traceability requirements.

The important thing is not to decide by trend. There are projects where a standard connector solves 80% of the problem with little effort. And there are others where forcing a generic platform creates more dependency than expected. The useful question is not “which technology is fashionable?”, but “which solution will let us operate and maintain this in a year?”.

A simple matrix helps:

• Transaction volume.
• Data sensitivity.
• Change frequency.
• Audit requirements.
• Internal ability to maintain the solution.

If the team will not be able to support it, the integration should be simpler, more visible or more outsourced. The real cost is not only building it, but operating it.

Integrate without losing control: the real goal

Integrating ERP, ecommerce and backoffice should not be seen as an end in itself. The objective is to make the business run with less friction, fewer errors and more ability to react. That requires prioritizing processes, defining ownership of each data item and designing for maintenance, not just for go-live.

When an integration is well designed, the team stops chasing information and can focus on real exceptions. If you are evaluating an integration and want to avoid a beautiful but unmanageable architecture, at Codefuente we usually start with that exact question: which operational problem should disappear first.