--- title: Legacy Image Provider to Cloudflare Images: Traffic... description: Mercari's Platform Network team shares how they migrated a legacy image transformation pipeline to Cloudflare Images while keeping existing URLs intact. Key... canonical: https://daily.dev/posts/legacy-image-provider-to-cloudflare-images-traffic-estimation-and-safe-rollout-gvq0ff3wg twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Legacy Image Provider to Cloudflare Images: Traffic Estimation and Safe Rollout | daily.dev og:description: Mercari's Platform Network team shares how they migrated a legacy image transformation pipeline to Cloudflare Images while keeping existing URLs intact. Key... og:url: https://daily.dev/posts/legacy-image-provider-to-cloudflare-images-traffic-estimation-and-safe-rollout-gvq0ff3wg og:image: https://api.daily.dev/og/posts/GVq0FF3Wg.png og:image:alt: Legacy Image Provider to Cloudflare Images: Traffic Estimation and Safe Rollout og:image:width: 1200 og:image:height: 630 og:locale: en --- [Mercari Engineering](https://daily.dev/sources/mercari) [Read post](https://api.daily.dev/r/GVq0FF3Wg) # [Legacy Image Provider to Cloudflare Images: Traffic Estimation and Safe Rollout](https://api.daily.dev/r/GVq0FF3Wg "Go to post") Mercari's Platform Network team shares how they migrated a legacy image transformation pipeline to Cloudflare Images while keeping existing URLs intact. Key challenges included TLS/SSL issues with legacy S3 bucket naming conventions, egress cost estimation due to Cloudflare's different compression behavior (WebP files up to 50% larger), and zero-downtime rollout mechanics. They resolved S3 access via host-header-style routing with Terraform, validated image quality through pixel-level comparison and adjusted quality settings, estimated costs using 30-day APPROX\_COUNT\_DISTINCT queries on access logs, and rolled out traffic gradually using regex-based image ID matching (from 0.1% to 100%) with a three-phase cache rebuild strategy to avoid S3 rate limit overloads. [#aws-s3](/tags/aws-s3 "Check all #aws-s3 posts") Aug 06•10m read time•From [engineering.mercari.com](https://api.daily.dev/r/GVq0FF3Wg "engineering.mercari.com") [](https://api.daily.dev/r/GVq0FF3Wg "Go to post") Table of contents [Abstract](https://api.daily.dev/r/GVq0FF3Wg "Abstract")[What the migration looked like](https://api.daily.dev/r/GVq0FF3Wg "What the migration looked like")[Migration challenges](https://api.daily.dev/r/GVq0FF3Wg "Migration challenges")[How we resolved it: S3 access from Cloudflare](https://api.daily.dev/r/GVq0FF3Wg "How we resolved it: S3 access from Cloudflare")[How we resolved it: image quality, egress and cost](https://api.daily.dev/r/GVq0FF3Wg "How we resolved it: image quality, egress and cost")[How we resolved it: zero-downtime rollout details](https://api.daily.dev/r/GVq0FF3Wg "How we resolved it: zero-downtime rollout details")[Conclusion](https://api.daily.dev/r/GVq0FF3Wg "Conclusion") 165 Impressions Comment Bookmark Copy Share your thoughtsPost [](https://daily.dev/sources/mercari) [Mercari Engineering](https://daily.dev/sources/mercari "https://daily.dev/sources/mercari") Mercari's platform is a resource for developers and technology enthusiasts, offering insights into e... 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