File-Based Integration: The Old Workhorse That Still Earns Its Keep
APIs are fashionable, but plenty of systems still trade files. Done properly, file-based integration is reliable, auditable, and perfectly respectable.
In a world chasing real-time APIs, file-based integration gets treated as old-fashioned. But plenty of systems, especially government, banking, and legacy providers, still trade files, and done properly, a file-based integration is reliable, auditable, and nothing to apologise for. Fashion isn't the same as fit.
Nail the file specification
Layout, delimiters, encoding, headers, trailers, the receiving system is unforgiving about format. Get the specification exactly right, because a file a hair off spec is a file that gets rejected wholesale.
Confirm receipt, don't assume it
Producing a file isn't the same as the other side consuming it. Build in acknowledgement or reconciliation so you know the file arrived and was processed, not just that you sent it into the ether.
Handle the reject and resubmit cleanly
Files get rejected, a format issue, a bad record. Have a clean process to identify why, fix it, and resubmit, rather than a scramble each time. Rejections are normal; chaos handling them isn't.
Real scenario: a client dismissed their bank file integration as 'legacy' and under-invested in it, so when the bank tweaked the required format, files silently rejected and payments stalled. We treated the file integration with proper respect, tight spec, receipt confirmation, clean resubmit. Payments flowed reliably again. A file integration built well beats an API integration built badly. Respect the workhorse.