Integrations are the product, not the appendix
Teams scope the feature list carefully and leave integrations as a line item called “APIs”. That line item is where the schedule goes.
Access is the first dependency
Sandbox credentials for the ERP, the payment rail and the customer's identity provider take weeks to obtain in most organisations, and none of that time is engineering time. We request them during discovery so the waiting happens in parallel with design rather than in series with the build.
Credentials take weeks and none of that is engineering time, so the waiting has to happen in parallel.
Their constraints become your product
Rate limits, batch windows and eventual consistency in a system you do not control shape what your interface can honestly promise. A screen that implies instant confirmation over a nightly batch is a support ticket waiting to be filed. We surface the real timing in the design instead of hiding it.
Respect the spreadsheet
Every operation has one file that runs something important and will not be replaced by your product. Importing it cleanly, or exporting to it faithfully, is usually worth more to adoption than a feature on the roadmap.
