We kicked off 2025 by addressing one of the oldest “bottleneck” complaints in the serverless community. For years, the 6MB payload limit for synchronous Lambda calls forced us into complex workarounds involving S3 pre-signed URLs or asynchronous patterns for anything remotely data-heavy.

In January, AWS officially bumped Lambda response streaming capabilities to 200 MB. Technically, this is a massive shift in how we handle data egress. By implementing the response-stream content type, your functions can now push massive payloads, high-res media, giant JSON blobs, or real-time AI transcriptions directly to the client. This drastically reduces Time to First Byte (TTFB) because the client starts receiving data as it’s generated, rather than waiting for the entire 200MB buffer to close.

On the storage side, S3 Express One Zone, the high-performance, single-AZ sibling of S3, received a performance profile update. We saw roughly a 15% reduction in latency for small-object GETs. If you’re running high-frequency trading apps or real-time gaming leaderboards, this update effectively lowered your “distance to data.”

Engineering Tip: If you’re still using the old Invoke API for large reports, migrate to streaming. It simplifies your frontend logic and eliminates the need for “interim” S3 buckets.