#”Clojure(Script)?” Developers


Reporting to our CTO, you will be helping to build Yapster - working both on the client app and the back-end services. We are looking for 1-2 smart and capable developers to join our team and help us build the product faster and more robustly. Each day will present new challenges, requiring continual learning on the job.


  • Annual salary of up to £60k (dependent on experience)

  • 25 days annual leave + your birthday off

  • Flexible working as standard

  • Quarterly team offsites and regular social events

  • Fun, friendly office environment in the heart of Soho

About Yapster:

Yapster is an investor-funded retail & hospitality tech start-up. Our mission is to empower people working in roles previously untouched by decent enterprise technology. With your help, our chat app will be downloaded, used and loved by millions of workers operating “on the shop floor” of the UK’s favourite High Street brands. Customers include Ann Summers, Caffe Nero and Krispy Kreme.

Based near Old Street, we’re a friendly, fun, and fast-growing team united by a passion for building a first class product and company culture. Our product is only as good as our team - you can expect to work alongside brilliant people and join a fast-paced culture in which everyone relishes getting ‘stuck in’.

The dev team:

Yapster’s dev team currently consists of 4 engineers (including the CTO). We are self-motivated, enthusiastic and bring a wealth of different experience - we are welcoming of new viewpoints and the increased problem-solving capability they bring to our development process. We are currently quite un-siloed and each of us can, and do, work on any part of the Yapster application (front-end, back-end, Android, iOS, web). We are currently mostly working remotely with a regular office-day in London each week - this has advantages for optimising flow and minimising interruptions, but we are also wanting to establish a more office-based dev presence, so if you prefer to work from our office that’s also an option.

Major Responsibilities / Accountabilities:

  • Software development: Working with Co-founder CTO to develop features on the Yapster app(s) and backend.

  • DevOps: Working with Co-founder CTO to reliably deploy and monitor the Yapster app and backend components.

Technology stack

Yapster consists of a mobile and web app, and the backend, together forming an asynchronous messaging platform. It’s built on modern storage and messaging components, there is code-sharing between front and back-ends, and pervasive schema-checking. Almost everything is implemented in either Clojure or ClojureScript.

The Yapster app is available on iOS, Android and browser platforms, and is written in ClojureScript with Reagent and re-frame. We are using Apache Cordova to deploy the app to iOS and Android.

The back-end has a REST API implemented in asynchronous Clojure with Yada, and a stream-processing component built on Kafka+Onyx. We use Apache Cassandra for persistence and Apache Kafka for persistent messaging. The back-end is deployed to AWS in containers on DC/OS.

Required skills and experience - technical:

  • Clojure || ClojureScript (both is a bonus!)

  • Linux

  • Good understanding of functional programming paradigm

  • Familiarity with web apps, HTML and CSS (not visual design)

  • Happy to pull apart other people’s code to find out why something isn’t working as expected

Required skills and experience - personal:

  • Good written and oral communications skills

  • Able to work with little direct supervision (though there will be plenty of supervision available, it won’t always be co-located)

  • Able to work effectively in a team environment where team members may not be co-located

  • Self motivated and proactive

  • Excellent problem-solving skills

  • Interested in better ways of doing things, yet remaining aware of the realities of delivering features to customers

  • Flexible approach to day to day tasks and coping with a challenging workload

Desirable skills and experience - but can be learned on the job:

  • Asynchronous programming techniques

  • Data modelling and operational experience with Apache Cassandra

Desirable education/certifications:

  • A demonstrable understanding of computer architecture and operation - whether acquired through formal education or otherwise isn’t important.

Diversity policy:

We aspire to build a team that properly reflects the communities we serve and welcome applications from people with diverse perspectives and backgrounds.

How to apply

Please send your CV to hr@yapster.info with Software Developer Application in the subject line.