API integrations: turn separate applications into a manageable data flow

Choose the entry point for your situation

If no integration exists yet, begin with the business event. Who performs the current action and which information is copied? Describe the next step you actually want. The connector-versus-custom guide then helps investigate the simplest suitable solution. The cost guide translates the scope into comparable work without attaching an arbitrary price to an assignment that has not yet been understood or tested.

Take a different route when a connection already exists. Incorrect records often make identity and ownership the first investigation points. Missing transactions require understanding receipt, processing and reconciliation. During an incident, begin with impact and preserved evidence. Replacing an existing connection before that investigation can simply reproduce unclear business rules in a different technical product, leaving the fundamental source of mistakes unchanged.

Describe the handover before selecting technology

Use a sentence with a starting event, a condition and an outcome. For example, when an employee approves an order, one reviewable draft appears under the correct accounting customer. Identify what remains for an employee to assess and which actions intentionally remain outside automation. This gives a more useful assignment than listing product names that should somehow communicate with each other.

Work through one exception as well. What happens when the customer reference is missing or an order changes after approval? A simple process with an explicit exception route can be more valuable than a broad connection attempting to resolve everything. The first release should be useful and manageable. Later expansion can then rely on actual evidence about volumes, missing details and the decisions employees encounter in daily work.

Compare existing solutions using the same trial

First investigate whether a connector supports the required event, fields and recovery behaviour. An integration platform can provide more configurable components without taking responsibility for the business rules you select. Custom implementation can support particular meanings and exceptions, together with its maintenance responsibilities. Scenario evidence is more useful than a general ranking in which one technology is assumed to be inherently superior.

Use the same normal instruction, missing field and repeated submission for every candidate. Inspect destination records and the messages shown to employees. Distinguish what demonstrably works, what requires configuration and what is unsupported. This prevents comparing one product’s polished demonstration against a substantially more demanding acceptance list for another. It also identifies whether a modest adaptation could be sufficient before committing to a broader development project.

Clarify identity and authority over information

Recognising an organisation is different from comparing two strings. A changed name, shared email address or second administration can make simplistic matching unreliable. Preserve source and destination references after a relationship has been confirmed. Review ambiguous matches instead of silently converting uncertainty into a new record or an automatic merge that may be difficult to undo later.

Then assign authority per field. A CRM might own commercial contacts while accounting owns approved billing information. That is one possible arrangement rather than a universal rule. The synchronisation guide examines versions, empty values, removals and concurrent changes. A shared field contract allows technical and business colleagues to follow the same decisions, and provides a clearer basis for investigating a disputed update than assuming that the latest arrival must be correct.

Where applications use different concepts, a bounded translation layer can make the differences explicit. Microsoft describes that design choice in its Anti-Corruption Layer pattern. Assess whether the boundary helps your mapping; the pattern does not require introducing another system in every project.

Microsoft Azure Architecture: Anti-Corruption Layer ↗

Design repetition and timeliness together

Messages may arrive again or be processed in an unexpected order. The integration therefore needs to distinguish a new instruction, repetition and a change to existing work. The duplicate-prevention guide investigates that boundary. The webhook-versus-polling guide then examines how changes arrive and how a backlog or missed event can be discovered without relying only on a successful delivery notification.

Fast notification and complete reconciliation serve different purposes. A combined approach can work when both use common business protection. A fictional target might be finding a missed order later while preventing a delayed notification from creating another draft. Test the interaction. Two individually successful paths can cause unintended repeated actions together when they do not share identity, scope and a consistent view of previously confirmed processing.

Treat cost as a bounded assignment

Access, field meaning, business rules, verification, recovery and support all influence implementation effort. Connecting the same two products can mean copying contacts or handling order changes in both directions. Those are different assignments. Make included work and exclusions explicit. Investigate uncertain API capabilities before committing every aspect of implementation, especially when access to the required administration has not yet been provided.

Use actual proposed rates and subscriptions for your own budget. Separate setup, continuing use and human checking. Released capacity is not automatically reduced expenditure. Decide how to measure whether the process actually reduces repeated entry, investigation or uncertainty about unfinished work after launch. The same measurement helps determine whether later expansion is worthwhile, rather than treating a growing count of automated tasks as evidence of business value by itself.

Prepare introduction and daily recovery

Separate historical loading from ongoing changes. Existing records may need a supervised matching exercise, while new instructions follow a different route afterwards. Introduce a limited selection, check contents and references and retain the decisions. A second execution should understand previous mappings instead of treating every relationship as unknown and attempting to recreate work already completed during the first run.

Define a temporary operating method for interruption. If employees continue manually, resumed processing must recognise that work. The recovery guide separates cause, uncertain results and backlog. A green server indicator does not close an incident. The operational owner should be able to assess whether relevant business actions are confirmed, deliberately excluded with evidence or explicitly awaiting a responsible decision about how they can proceed safely.

Build a transferable first release

At handover retain a system map, field mapping, account inventory, acceptance cases and recovery instructions alongside code. Assign responsibility for business review and technical operation. Ask another authorised person to investigate a representative exception using the instructions. This exposes documentation that appears complete on paper but lacks essential access or explanation when somebody tries to use it during an actual problem.

Prepare an initial conversation with one example instruction, two exceptions, the applications involved and named owners. Use safe test information and keep credentials out of public enquiries. The service pages can then support discussion of the actual assignment. This cluster helps establish which flow is needed, which decisions have been made and what a working delivery must demonstrably mean in your organisation’s own circumstances.

Explore each decision

Turn the explanation into a project decision

Record your assumptions, unknowns and acceptance checks in the matching tool. Use the service guides to discuss delivery and scope.

• API integration ↗
• CRM integration ↗

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