ROAS is revenue divided by spend. The hard part is the revenue: platform-reported ROAS counts conversions by the platform's rules, often claims sales another channel closed, and never sees refunds.
Connect Meta Ads, Google Ads or TikTok Ads by signing in and BrainyMetrics pulls spend per day and ad, with campaign, ad set and ad ids and names, impressions and clicks. The first sync imports the last 30 days; afterwards it runs every hour and re-reads the last three days as platforms adjust. Other networks import by CSV or API. Spend joins attributed revenue through the same ids your ad URLs carry, with no manual mapping.