Since we shipped Polar we've been listening to feedback from our users as to the default behavior and functionality of web capture.

Web capture (or just capture) is what we call converting an HTML page to a format that can be persisted and used within Polar.

This code started off as an advanced proof of concept but it had a few issues in practice that holds it back from perfectly solving the problem of offline web pages as documents.

Here's what we're working on in the background.


EPUB will become the default format. Internally, EPUB is just HTML and CSS and if we migrate web capture to use EPUB then this means we also support EPUB as a primary file format in Polar.

It also means less code to debug since everything is EPUB.

We're going to work on a converter to take our PHZ format and convert it to EPUB so that existing documents will convert in place.

Based on Web Extensions

We're going to migrate everything to a web extension.

This means the native Electron capture will migrate to being completely browser based.

Our goal is to support Chrome, Firefox, and Safari extensions during this process as our Firefox extension is nearly finished.

The advantages here are the ability to use regular chrome extensions like uBlock, Ad Block Pro, Mercury Reader, or Easy Reader.

The new extension will completely bundle the pages resources and send them to the Polar cloud or desktop app.

Fluid Layout.

The new format will not require a fixed document size like the previous version. This was needed due to the layout algorithm for placing highlights. The new version should support placing highlights based on text.

One UI change might be that area highlights for HTML documents will anchor to images since the flow can change this means that an area you select might move when you resize.

Mobile and Tablet Support

Once we've migrated to EPUB as a backend, captured content will work on mobile and tablet devices.

We're also going to have capture work on mobile by sending the raw URL to the Polar cloud backend and having it perform the capture for you in the background.

This way capture will work on all devices.

Lightweight Capture (URL only)

We're also going to work on lightweight capture where we store the URL only. I think for a lot of users it might not make sense to store 300k per document as part of Polar so storing just the URL and annotations will mean much lower storage requirements.


I think these issues will solve 95% of the initial problems we had with capture and make the entire platform much more reliable.

Posted on: Oct 06, 2019
Polar Team

Written by Polar Team
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