Distributed Persistent Rendering (DPR)

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Like Jamstack, Netlify is coining this term.

If your reaction is: great, a new thing I need to know about and learn, know that while Distributed Persistent Rendering (DPR) does involve some new things, this is actually a push toward simplification and leverages ideas as old as the web is, just like Jamstack.

It’s probably helpful to hear it right from Matt Biilmann, CEO of Netlify:

In that short video, he makes the point that React started out very simple and solved a lot of clear problems with JavaScript architecture and, as time goes on and it tries to solve more use-cases, it’s getting a lot more complicated and risks losing the appeal it once had in its simplicity.

Jamstack, too, faces this problem. The original simplicity of it was extremely appealing, but as it grows to accommodate more use-cases, things get complicated.

One of those complications are sites with many-thousands of pages. Sites like that can have really slow build times. It’s nice to see frameworks tackle that (Google “Incremental Builds {Your Favorite Framework}”), but heck, if you change one link in a site footer, you’re re-building the whole site based on that one change.

So instead of building many-thousands of pages during a build, say you just… didn’t. Until that page is requested once, anyway. That’s DPR.

Here’s Zach Leatherman doing that. He finds a spot on his site that generates some 400 pages on each build and tells Eleventy that instead of building it during the normal build process, defer it to the cloud (literally a lambda will run and build the page when needed).

Deferring those 400 pages saves seven seconds in the build. Say your site is more dramatic, like 16,000 pages. Scratch pad math says you are saving four minutes there. It’s not just time either, although that’s a biggie. I think of all the electricity and long-term storage you save building this way.

Here’s the Netlify blog post:

Just like coining the term “Jamstack” didn’t mean inventing an entirely new architecture from scratch, naming this concept of “Distributed Persistent Rendering” doesn’t mean we’re creating a brand new solution.

The term “DPR” is new to us, but in a lot of ways, we’re taking inspiration from solutions that have worked in the past. We’re simply reworking them to fit with modern Jamstack best practices.

I like that it’s not like this entirely new thing. I’m sure Netlify’s implementation of it is no joke, but for us, it’s very easy to think about:

  • Some pages are pre-built as usual
  • Some pages are not built (deferred)
  • When the non-built pages are requested for the first time, then they are built and cached so they don’t need to be built again.

That’s it, really.

It reminds me of how old WordPress caching plugins used to work. When a page was requested for the first time it would run the PHP and MySQL queries and all that, then save the result as an .html file to the disk to serve subsequent requests. Not new, but still efficient.

The trick to a DPR architecture on Netlify is using their (beta) On-Demand Builders, so here’s the blog post that explains everything and will get you to the docs and such.