Web applications & APIs

Connecting your software through APIs:
how can you avoid duplicate data entry?

DEV2PUB team · 9 November 2026 · 6-minute read

A customer is created in your CRM, then entered again in your management software. An order arrives on your website, but someone still has to copy its details into the tool your team uses. Your applications do their jobs; moving information between them is what slows you down.

An API integration can automate these exchanges without replacing all your tools. First, you need to decide which data to transfer, which system is the source of truth and what should happen when a transfer fails. That planning turns a technical connection into something useful for your team.

Your tools can work together

CRMOne customer record

Entered at the source

→API→

Business applicationThe right information

Received · tracked · checked

Can an API make my software work together?

An API is an interface through which one application makes certain functions or data available to another program. Depending on what its publisher allows, it may let you retrieve a record, create a contact or update a status.

Having an API does not mean every operation is available. Before planning an automation, check the supported functions, required permissions, usage limits and access conditions under your subscription.

Start with a business question: “Which information does my team enter more than once, and why?” A precise answer helps identify the first exchange worth automating.

Which system should be the source of truth for each piece of information?

Connecting two tools without deciding which one holds the authoritative information can simply move the problem elsewhere. If an address changes in both the CRM and the management system, which version should you keep?

Assign a source to each type of data

One application does not have to be the authority for everything. The CRM might manage sales contact details while the business application tracks progress on individual cases. Teams need to understand this division, and the synchronization rules must reflect it.

For each piece of information, specify its source, destination, direction of transfer and who can edit it. Also define how empty fields should be handled: do they erase an existing value or simply mean “information not provided”?

Match records using a stable identifier

A name or email address is not always enough to identify a record. Two people can share a name, and a company can change its contact person. Plan a mapping between the identifiers used by both applications, with a process for reviewing ambiguous matches.

Should data sync immediately or at regular intervals?

Not every exchange needs an immediate transfer. An internal dashboard may work well with periodic updates, while an action that depends on a status change may require a shorter delay.

Two approaches can be considered: regularly querying an API, or receiving a notification when an event occurs. This notification is generally called a “webhook”. The choice depends on the applications’ capabilities and the delay your business can accept.

A webhook does not guarantee immediate, unique or ordered processing. Stripe, for example, explains that events can arrive more than once and in a different order from the one in which they were created. Each integration must account for its provider’s delivery rules. ^[1]

What happens when synchronization fails?

A connection can work during a demonstration yet remain fragile in everyday use. An outage, a rejected value or a change in access permissions all need a planned response.

Prevent duplicate records

If the same event arrives twice, the connector should recognize what it has already processed. Stripe recommends recording processed event identifiers to avoid processing certain repeated deliveries. ^[1]

For a business integration, the exact mechanism also depends on the destination application’s capabilities. The expected outcome should be easy to explain: retrying an operation must not accidentally create a second case.

Make errors visible and recoverable

Plan a way to track successful, pending and failed exchanges, with someone responsible for responding to alerts. A data-entry error needs a different response from a temporary outage: one needs correction, while the other may justify a controlled retry.

A queue can separate receiving a notification from processing it. GitHub recommends this approach to acknowledge webhooks promptly and process their data in the background. It also recommends HTTPS and validating the origin of notifications using a secret. The details are specific to each provider. ^[2]

Start with one workflow, then test the exceptions

Consider a fictional company that wants to create a case in its business application once a request is approved in its CRM. The first version could transfer only the reference, contact and service type.

Before expanding the project, testing should answer practical questions:

• What happens to a request that has already been transferred?
• What happens if a required field is missing?
• How does processing resume after the destination application has been unavailable?
• Does changing the contact update the correct case?
• Who steps in when an exchange remains blocked?

This scenario illustrates a method; it is not a client case study. Validation should cover exceptions as carefully as the normal workflow.

An existing connector or custom development?

An existing connector is worth considering if it supports the necessary exchanges and business rules. Review the data it handles, recovery options, volume limits, recurring costs and maintenance.

Custom development becomes relevant when the company’s workflow requires specific transformations, approvals or processes. It might take the form of a synchronization service or be integrated into a business application with a monitoring screen.

DEV2PUB develops custom business software and web applications. Reviewing which tools to retain and how they should exchange information is part of defining the project.

What should you prepare before discussing an integration?

Gather the software names and versions, any available API documentation, an anonymized workflow example and a list of the information to transfer. Include the approximate number of operations, acceptable delays and errors you encounter today.

The proposal should define the exchanges, tests, access requirements, monitoring and maintenance. Changes to an API or an application’s settings may require adjustments: ongoing support is part of the project.

Looking to connect your software in Toulon or the Var region? Tell DEV2PUB about your requirements, including the tools involved and the step your team currently repeats. We can review the integration options and define a useful initial scope.