No is correct because Azure Front Door will not Brotli compress responses that exceed the service compression size limits so a 25 megabyte XML response was simply not eligible for compression and you do not need to purge edge caches to force compression.

Azure Front Door applies response compression such as Brotli only when the client sends the appropriate Accept-Encoding header and when the response content type and size fall within the supported ranges. Large payloads are commonly excluded from on-the-fly edge compression to protect resource usage and throughput so a 25 megabyte file will typically be served uncompressed even though the feature is enabled.

Because the XML was not compressed at the edge in the first place purging cached content will not change that behavior. Compression is determined at response time based on headers and size so you can either enable compression at the origin for large files or check the documented size limits and content type rules if you need them to be compressed by the CDN edge.

Yes is incorrect because removing cached objects from the edge will not cause Azure Front Door to compress responses that are too large. Purging only clears stored content and does not alter the compression eligibility checks that prevented Brotli from being applied to the 25 megabyte XML.

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