Software Architect


London, GB
  • Job Type: Full-Time
  • Function: Engineering Software
  • Post Date: 06/04/2021
  • Website:
  • Company Address:

About Callsign

Callsign is the app that makes identification quick, secure and private. No more passwords, forms and even business cards. Use your single Callsign across multiple channels and applications, at work and at home.

Job Description

Software Architecture at Callsign is a mix of designing new solutions and working closely with engineering feature teams to ensure that they are implemented completely and to a high standard. A typical new feature often involves coordinating with Solution Architects and Subject Matter Experts (SMEs), reading reference documentation and specifications and developing proof-of-concept code with the aim of demonstrating the principle and removing any risk involved in the feature - with particular attention to security, maintainability and extensibility. The Software Architect is also responsible for providing adequate documentation and support for engineering teams - both during feature development and during the maintenance/bug fixing phase.


The Software Architect will:

  • Take product requirements and a solution design and create a POC from which a full production solution can be developed
  • Guide Engineering, Quality Assurance and DevOps teams in the technical aspects of creating flexible solutions that meet requirements and scale to 1000s of TPS
  • Ensure that the developed software is in line with the designed solution
  • De-risk new projects by providing a reference POC implementation to development teams, and continuing to work closely with the teams during the Agile development process
  • Work across all areas of the company - from authentication, identity and access management and machine learning. Act as a stand-in SME where required and rapidly develop an understanding of new areas or technologies
  • Work across the full stack - taking responsibility for the solution from the database all the way to the browser if necessary.
  • Have a security focus - securing products protecting our customers data as first principle
  • Collaborate with Product Owners to develop product architectural blueprints and roadmaps that align with architectural standards and technology strategy
  • Support Callsign's client facing teams with product or technical knowledge in response to requests from clients; and
  • Assist Callsign's support team by providing technical documentation, advice or product enhancement requests


The Software Architect will have a high level of technical expertise - particularly in Java, but also in database design, testing and DevOps. They will possess excellent problem solving and analytical skills in order to identify and communicate effective, pragmatic and timely solutions. As an experienced hire, the Software Architect will be able to communicate effectively at all levels both internally and externally and clearly demonstrate their technical leadership.

The Software Architect will have:

  • Demonstrated ability to lead teams and provide technical solutions that meet both functional and non-functional requirements
  • Expert knowledge of Java and Spring Boot. Good knowledge of SQL and no-SQL databases
  • A track record on delivering high performance distributed systems
  • Good understanding of general cryptography (Encryption, signatures, hashing) and authentication protocols (Oauth, OpenID connect, SAML, TLS)
  • Previous experience with containerised applications using Docker, ideally with Kubernetes
  • A good understanding of a cloud infrastructure (AWS, Azure or Google) and its associated costs
  • Broad understanding of authentication mechanisms
  • High level understanding of machine learning and artificial intelligence techniques
  • Familiarity with working in an Agile environment
  • Excellent written and oral communication skills
  • The ability to work effectively in a team or solo environment with minimal supervision

Desirable Experience

The Software Architect could have:

  • Professional qualifications in an architecture related domain (CISSP, TOGAF, AWS Solution Architect etc.) illustrating their commitment to learning and keeping their skills up to date
  • Deep knowledge of authentication protocols such as Oauth, OpenID connect, SAML, advanced cryptography etc.;
  • Experience with AWS managed services like EKS, RDS and DynamoDB
  • Recent hands on experience in one or more of the following: GitOps techniques, Terraform, Bash, Python, AWS, Kubernetes, SQL and Key / Value Pair databases
  • Experience in a Financial Services environment with PSD2 / Open Banking or Secure Customer Authentication exposure;
  • Experience in an Insurance, Healthcare or other Public Services environment
  • Experience of specifying or developing authentication and authorisation solutions


Automatic Option:

  • Health Insurance – single
  • Life Insurance
  • Employee Assistance Program
  • 3 months full pay maternity & 2 weeks full pay paternity (if the statutory minimum is met)
  • 25 days of annual leave + Callsign Bank Holiday (not included in holiday allowance)
  • Free financial advice


  • Cycle to work scheme
  • Wills and Estates – our benefits provider has partnered with a third party who offers a discount
  • Home Utilities our benefits provider has partnered with a third party who offers a discount
  • Cycle Insurance
  • Health cash plans
  • Cyclist protection
  • Discounted gym membership

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Disclaimer: Local Candidates Only
This company does NOT accept candidates from outside recruiting firms. Agency contacts are not welcome.