The most common API integration mistakes are unclear data ownership, failures that happen silently, duplicate records, ignoring API limits, and no monitoring. Each one is avoidable with a little design up front: decide which system owns each record, handle errors and retries deliberately, and make every integration observable.
1. No clear owner for each type of data
When two systems can both edit the same record, they eventually disagree. Decide which system is the source of truth for customers, orders, products and invoices, and sync in that direction.
2. Failures that nobody notices
An integration that fails quietly is worse than none, because people assume data is correct. Log every run and alert someone when something needs attention.
3. Duplicate records
Retries and repeated webhooks can create the same record twice. Use unique identifiers and check whether a record already exists before creating it (idempotency).
4. Ignoring rate limits and API changes
APIs limit how many requests you can make and change over time. Respect limits, queue work when needed, and keep track of API version updates.
5. Hard-coding business rules
Mapping rules, such as which status means 'paid', change. Keep them in configuration where they can be updated without rebuilding the integration.
6. Weak security
- Use secure authentication and rotate credentials
- Grant only the access each integration needs
- Encrypt data in transit and avoid logging sensitive fields
7. Testing only the happy path
Test with real data, including missing fields, duplicates, slow responses and outages, before going live.
Want help putting this into practice? Explore our Systems Integration services or see related work in our Australian food van and event catering business case study.
Have systems that don't communicate?
Discuss Your Integration