Onwards & Upwards — Squarespace Dev Tools

About

Stop navigating Squarespace like it's 2015.

Squarespace's admin panel buries the tools you actually use every day. Custom CSS is three clicks away. Code injection is somewhere else entirely. The device preview gives you desktop or mobile, nothing in between. We built this extension because we were tired of wasting time on an interface that wasn't built for professional developers.

What it does:

One-click access to Custom CSS and Code Injection, added directly to the Squarespace toolbar — right where you're already working. No new panels, no floating widgets. The buttons sit alongside the native Edit button and inherit Squarespace's own styling so they look like they were always there.

The device preview gets a full replacement. Instead of a binary desktop/mobile toggle, you get a proper device dropdown covering the full Apple lineup — MacBook 13″ through 16″, every iPad from the mini to the 13″ Pro, and iPhones from the 13 Mini to the 17 Pro Max. All dimensions are correct CSS logical pixels, not physical screen resolutions, so what you see is what your users actually get. Switch orientation with a second dropdown. Hover the info icon to confirm the exact pixel dimensions at a glance.

Built for Squarespace professionals. If you're building client sites on Squarespace every day, this gives you back time you didn't know you were losing.

By Onwards & Upwards — a UK-based Squarespace design collective that pushes platform limits and delivers agency-quality without the bloat.