# Planning a Software Integration Before Writing the First API Call
Connecting two business systems is often described as moving data from one place to another. The harder work is agreeing on what the data means, which system owns it, and what should happen when only part of the operation succeeds.
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# Name the source of truth
For each shared field, choose the authoritative system. A customer may have an account in a CRM and a billing profile elsewhere, but that does not mean both systems should freely overwrite the same address. Record ownership field by field and define which changes must travel in each direction.
Use stable identifiers to match records. Names and email addresses can change or be shared. When there is no reliable common identifier, design an explicit matching and review process before importing production data.
# Write the failure story
Suppose the CRM saves a new job but the scheduling system is unavailable. Is the job pending, rejected, or eligible for a later retry? Give the state a name and make it visible to the people who depend on the workflow.
Retries need a rule for recognizing operations already completed. Otherwise, a lost response can produce duplicate appointments or duplicate records. Agree on who investigates failures that cannot be retried automatically.
# Design the first reconciliation report
A connection can appear healthy while quietly missing records. Plan a report that compares expected and received changes, including a time window and the reason for each mismatch. The report should help an operator take a specific action rather than display only an unexplained error count.
# Launch with a bounded sample
Start with a controlled group of records and verify both sides. Include updates, deletions where supported, permission changes, and retries. Keep a way to stop synchronization without losing the evidence needed to reconcile pending work.
An integration is ready when its normal path and its recovery path are understandable. The API call is only one part of that agreement.
Published by Tg Apps, a software development company building business applications, backend APIs, and integrations.