# Best Practices ## Recommended setup


Export Contacts attributes alongside Contacts	The Contacts entity alone won't tell you what your custom fields mean. Always add Contacts attributes as a second source in the same data flow so you have field definitions handy.
Use multiple sources in one data flow for list-level contact exports	If you need contacts from several lists, add each list as a separate Contacts lists contacts source and use the Append transformation to combine them into one output table.
Join CRM deals with pipeline stages	CRM deals contain a stage ID, not a stage name. Add CRM pipeline stages as a second source and Join on stage ID to get human-readable stage names in your reports.

## Data refresh and scheduling


Wait a few hours after a campaign send before syncing	Open and click metrics continue updating after a send. Scheduling a sync several hours post-send gives you more settled engagement data rather than preliminary counts.
Use a fixed start date for campaign history	Set your start date to the earliest campaign you care about and leave it fixed. This avoids re-pulling the same historical data unnecessarily on every sync.

## Performance optimization


Separate high-volume contact exports from CRM syncs	If you have a large contact database, running it in the same data flow as CRM entities can slow things down or trigger rate limits. Keep contact-heavy and CRM-heavy flows separate.
Use Aggregate for campaign reporting	Instead of exporting every campaign row to a spreadsheet, use the Aggregate transformation to summarize metrics (e.g., total sends, average open rate by month) before writing to the destination.

## Common pitfalls {% hint style="danger" %} Do not share or commit your Brevo API key to public repositories or spreadsheets. If exposed, regenerate it immediately in Brevo under Account settings → SMTP & API → API Keys, then update the key in your Coupler.io data flow. {% endhint %} {% columns %} {% column %} **Do** * Add Contacts attributes as a companion source when exporting Contacts * Join CRM deals with pipeline stages for readable stage names * Verify an entity has data in Brevo before troubleshooting a missing-data issue in Coupler.io * Use Append to merge email and SMS campaign data into a single performance table {% endcolumn %} {% column %} **Don't** * Use a restricted API key if you need access to CRM or account-level entities * Expect real-time accuracy on open/click rates immediately after a campaign send * Pull Contacts lists contacts without first confirming the target list has subscribers {% endcolumn %} {% endcolumns %}