[world32]

Its entirely possible to get a junior ruby on rails job outside of london earning 30k, even 35k is not unheard of for a junior.

Just go on any of the big job sites, search "Junior Ruby on Rails" in your area and take a look at whats available. If you find some good jobs, apply, go for an interview - if you get an offer put that to your current employer, maybe they will match it, if not you now have the option of leaving to a higher paid job if thats what you want. Its pretty simple really!

EDIT: Sorry I read that you are "outside london", but really you said you are "just outside london" - does that mean you can commute into london? If so then at 23k you are being paid far below market rates.

[unicornfinder]

I'm 20 minutes give or take by train from central London.

Basically I'm a sole developer for this company - I do everything from developing the Rails app itself to managing a bunch of servers running Docker / Docker Swarm. Fun.

[world32]

Thats great, you are gaining a TON of really valuable experience. It also means that you are worth a hell of out lot more to this company than 23k. If you were to quit and they had to hire somebody to fill this role, they would have a very hard time finding somebody to do all that at 23k, even at 35k it would be difficult. Junior developers are not really expected to be able to do everything that you're doing right now.

If I were I would start applying to jobs, and when they ask you what salary you would expect I would go for 35k, you could reasonably push it to 40k depending on how confident you are at negotiating.

Feel free to PM me if you have anymore questions.