Senior Software Engineer

Tact; Greater London; Hybrid; GBP 108,000 - 132,000; Full time

Benefits offered by this job

Hybrid work option

Health insurance

Pension

25 days holiday + bank holidays

Tech kit

Learning and development

Job summary

Tact is hiring a Senior Software Engineer in London, hybrid, focusing on greenfield AI and data analytics for hedge funds, asset managers and professional credit investors. You will own end-to-end delivery, architect systems, and implement AI features using Node.js, Python and AWS.

The role emphasizes hands-on coding, architectural ownership, and delivering production-grade software in a fintech environment with meaningful impact.

Qualifications

• Strong AWS knowledge.
• Experience designing architecture and leading technical delivery.
• Experience in finance or financial services.
• Hands-on experience building AI/LLM features into products.
• Relational database experience, PostgreSQL preferred.
• DynamoDB and Elasticsearch are a bonus.

Responsibilities

• Design architecture and make key technical decisions.
• Build greenfield AI and LLM-powered features.
• Write production code across Node.js and Python.
• Work with AWS and Infrastructure as Code.
• Design and develop databases, especially PostgreSQL.
• Lead other engineers through delivery without people management.

Skills

AWS

Architecture

Financial services

AI/LLM features

PostgreSQL

DynamoDB

Elasticsearch

Job description

Senior Software Engineer // London hybrid // Fintech // £120,000

Want to take ownership of greenfield AI projects in a growing fintech?

You'll be joining a growing London fintech building data and analytics technology for hedge funds, asset managers and professional credit investors.

They've built their reputation around high-quality financial data and are now pushing further into AI, LLMs and agent-based products. With an engineering team of around 14 people, you'll have the chance to work on greenfield technology, influence how new products are built and have a genuine impact without getting lost in a huge engineering organisation.

The role

You’ll take projects from idea to production, designing the architecture, making technical decisions, writing the code and leading delivery.

You'll be working across Node.js, Python and AWS, taking ownership of:

• Designing architecture and making key technical decisions
• Building greenfield AI and LLM-powered features
• Writing production code across Node.js and Python
• Working with AWS and Infrastructure as Code
• Designing and developing databases, particularly PostgreSQL
• Technically leading other engineers through delivery

This isn't a people-management role. You'll stay close to the code while having significant technical and architectural ownership.

What they're looking for:

• Strong AWS knowledge
• Architecture and technical leadership experience
• Previous experience within finance or financial services
• Practical experience building AI/LLM features into products
• Database experience, ideally PostgreSQL
• DynamoDB and Elasticsearch are a bonus

What's on offer

• 2 days per week in central London
• Greenfield AI and agent-based projects
• 25 days holiday + bank holidays
• Health insurance and pension
• Choice of high-quality tech kit
• Learning and development

If you want to stay hands-on, solve complex engineering problems and help shape new AI-powered products, this is an opportunity to do it in a growing fintech where your work will have real impact.