AirBlade Software

A software studio specialising in SAAS web applications

I'm Andrew Stewart — AirBlade is my company.

I have been producing software since 2000: writing it, running it, supporting and evolving it. In at the deep end with J2EE at Reuters, Razorfish, Aspect Capital, and the UK government; and then going solo in 2006 and switching giddily to Ruby.

I have been using Rails continuously since v1 in 2006. I happily ignored all the SPA nonsense in the 2010s, stuck with Rails, and was delighted when Stimulus and Turbo came along. I'm primarily a Rubyist but seem to have become the UK's no. 1 Vimscript programmer too 😂

I have worked in a variety of fields, from fintech to fashion to national security. I set up and ran a subsidiary in Germany for a few years and can confirm the German tax office loves long words and complicated forms.

I have an M.Eng from Cambridge University (Trinity College, graduated in 1999).

Outside work I love windsurfing and CrossFit.

Andrew Stewart photo

Main Products

DoubleAgent screenshot


Launched: October 2017

DoubleAgent automates time-consuming book-keeping tasks in FreeAgent, e.g. auto-reconciling Stripe and GoCardless payouts.

It hides considerable complexity with a clear UI and saves people a lot of time. It is built on top of Factor, my Ruby client for FreeAgent's API.

Customers' comments: extremely useful, what a great tool, a big time-saver, your pricing is way too low!

Sparkle screenshot


Launched: July 2008

Sparkle is a sample-tracking system for Fashion PR agencies and brands. Can be used in English or German.

It's overdue a fresh coat of paint but it works brilliantly.

Customers said, It has transformed my business, It is a competitive advantage for us, The service Andrew provides is impeccable.

Fledgling Products

In production but not generally available yet

LORHub screenshot

Letters of Recommendation

Launched: July 2021

LOR Hub helps manage the writing of recommendation letters for lab members and academics, from collating all the necessary information to tracking progress against deadlines. Used at MIT.

Early feedback: very useful, we are much more organised now.

Colloquio screenshot


Launched: July 2019

Colloquio helps labs and research groups work together more effectively by centralising all the reference information people need. Used at MIT.

Early feedback: a hit with the lab, it's super.

By-Products & Open Source

Factor screenshot


Launched: August 2017

Factor is a zero-dependency Ruby client for FreeAgent's API. It's used by DoubleAgent for all interaction with FreeAgent, and has shown its mettle and ergonomics over 4 years of constant production use.

Beyond CRUD of FreeAgent's resources, it handles typing, auto-pagination, automatic back-off and retry, getting and refreshing OAuth access tokens via command line or web, curl output for debugging, and more.

Quo Vadis screenshot

Quo Vadis

Relaunched: May 2021

Multifactor authentication for Rails 6 and 7, designed in accordance with the OWASP Application Security Verification Standard.

Quo Vadis makes it simple to integrate 2FA and modern authentication requirements into your Rails app, with a minimal footprint.

Stimulus Datepicker

Launched: April 2022

A Stimulus-powered, accessible datepicker which uses strftime directives to parse/format dates.

stimulus-datepicker makes it trivial to add a datepicker to your Rails app.

Smash into Vim screenshot

Smash into Vim

Launched: March 2010

I wrote PeepCode's Vim screencast, one of their top three bestsellers. It was one of the few kept by Pluralsight when they acquired PeepCode. It still sells well after all this time.

People said, terrific, full of gems, a must-have, so much good stuff here, helped me immensely.

It wasn't my first time as a PeepCode author: back in 2008 I wrote Rails 2 Plugin Patterns, a 100 page PDF. There weren't many good resources at the time for learning how to extend Rails.

Outstanding work; this has bumped up my efficiency and knowledge tremendously, fantastic, very well written, and you explain complicated nasty stuff with nice simple examples.

vim-gitgutter screenshot


Launched: February 2013

I wrote and maintain this Vim plugin which shows git diff markers in the sign column and makes it easy to preview and stage hunks and partial hunks.

Wonderful – Greg Kroah-Hartman (Linux kernel maintainer). Awesome – Ilya Grigorik (Principal Engineer at Shopify). This might be the best vim plugin I've ever seen – Steve Klabnik (Rust core team).

7.6k stars on GitHub as of April 2022.