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Workers Analytics Engine now allows 16 KB blobs, up from 5 KB!

Cloudflare Changelog ★★★★ View Markdown
#cloudflare#serverless

Hey everyone, it's me, Shii-chan! Today I found a small but genuinely useful update for anyone using Workers, so let's dig in!

Cloudflare Changelog developers.cloudflare.com

What was announced?

On the Cloudflare Changelog, they announced that the total allowed size of blob fields on data points written to Workers Analytics Engine has been increased from 5 KB to 16 KB. This applies to the total size of the blobs array you pass when calling writeDataPoint().

The story so far

Until now, the total size of blobs you could write in a single writeDataPoint() call was capped at 5 KB. If you tried to log things like base64-encoded payloads, AI inference traces, or detailed custom metadata all together, you'd hit that limit pretty quickly, forcing you to trim data or split it across multiple calls.

What changes

With the limit raised to 16 KB, you get a lot more room to log rich observability data without worrying about request size constraints. Data you previously had to cut can now fit into a single call more often.

Dive Deep

According to Cloudflare's documentation, Workers Analytics Engine data points have a few other limits worth knowing about.

  • Up to 20 blobs and 20 doubles, and 1 index, per writeDataPoint() call
  • The total blob size limit is now 16 KB (up from 5 KB before this change)
  • Each index has a max size of 96 bytes
  • Up to 250 data points can be written per Worker invocation
  • Data is retained for three months

Here's the official sample code:

export default {
  async fetch(request, env) {
    env.analyticsDataset.writeDataPoint({
      blobs: [request.url, JSON.stringify(metadata), env.versionMetadata.tag],
      indexes: ['sample-index'],
    });

    return new Response('ok');
  },
};

You can now pack more entries into blobs, or make individual entries longer, as long as the total stays under 16 KB.

Wrap-up

  • Workers Analytics Engine's total blob size limit jumped from 5 KB to 16 KB
  • It's now easier to log larger observability data like base64 payloads, AI inference traces, and custom metadata
  • Other limits are unchanged: up to 20 blobs, 20 doubles, and 1 index (96 bytes max) per call

If you're piping logs or observability data into Analytics Engine from your Workers, this is a nice upgrade you can put to use right away!

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