Lead / Principal Engineer - Full Stack

Sahaj Software; Greater London; On-site; GBP 110,000 - 170,000; Full time

Benefits offered by this job

Unlimited leaves

Life insurance & private health

No hierarchy

Open Salaries

Job summary

Sahaj Software is seeking a Principal Consultant to join small, high-ownership teams and drive architectural direction while staying hands-on. You will frame problems with customers, shape approaches, and mentor teams through complex technology and business decisions.

The role blends consulting and delivery in data-heavy, distributed environments. You'll work with customers and engineers, translating goals into strategy, and leading technical workshops to ensure scalable, secure systems.

Qualifications

• Demonstrable building software systems in complex environments.
• Strong engineering fundamentals; expert in at least one language, ideally polyglot.
• Hands-on experience designing and delivering distributed systems at scale.
• Deep grasp of architecture, system design, and engineering trade-offs.
• Direct experience working with customers and business stakeholders.

Responsibilities

• Frame problems and propose solutions; translate business goals into a technology strategy.
• Lead discovery sessions, architecture reviews, and technical workshops.
• Stay hands-on across design, implementation, and review; guide delivery with teams.
• Mentor practitioners, manage stakeholders, and influence organisations through decisions.
• Operate across technology domains: distributed systems, data engineering, DevOps/SRE.

Skills

Software systems

Distributed systems

Polyglot language

Architecture trade-offs

Customer engagement

Job description

• Small teams, high ownership, flat structures
• Radical compensation transparency
• Sense of ownership in collective success
• Work with exceptional people who deeply care about their craft

A different kind of organisation

• Small teams, high ownership, flat structures
• Radical compensation transparency
• Sense of ownership in collective success
• Work with exceptional people who deeply care about their craft

The role

As a Principal Consultant, you're often the first person a customer meets to brainstorm a business problem. You should be at home debating distributed systems with engineers and framing decisions with leadership. You'll frame the problem with customers, shape the approach with the team, provide technical direction, and stay hands-on through delivery. You will work in self-managing, experienced, small, and high-impact teams, solving hard problems. This is a consulting & tech delivery role and while you will not have direct reports, you will regularly influence teams, mentor practitioners, manage stakeholders, and guide organisations through complex technology and business decisions.

What the work looks like

We can't promise which problem you'll pick up, but the menu right now looks something like this:

• Redesign a ClickHouse schema so an ad buyer can query 85 billion rows in under two seconds, and discover that pre-exploding the rows 168x is actually the right answer.
• Keep a vehicle telemetry platform moving billions of messages a day without the Kafka consumers falling over.
• Build the engineering spine of a mobile wallet used by more than two billion people across four continents.
• Ship the data product behind peer-review submissions for one of the world's largest scientific publishers.

The list changes every quarter. The pattern doesn't: data-heavy, distributed, and often sitting on top of something that already exists and isn't perfect.

What you'll do

Frame Problems & Propose Solutions

• Help customers find the right problem before jumping to a solution.
• Facilitate discovery sessions, architecture reviews, and technical workshops.
• Translate business goals into a technology strategy and an execution plan.

Lead Through Technical Excellence

• Stay hands-on; contribute directly to design, architecture, implementation, and review.
• Make pragmatic calls balancing business needs, engineering quality, and delivery timelines.
• Guide teams to build scalable, resilient, secure systems and the practices that keep them that way.

Influence, Advise, and align

• Act as a trusted advisor on technology and investment decisions; assessments, due diligence, advisory.
• Build trust and alignment across Sahaj and customer teams
• Converge competing priorities into a path forward.
• Communicate complex ideas clearly to technical and non-technical audiences.
• Shape new work through discovery and proposals; mentor others and raise the bar as you go.

Operate Across Technology Domains

Distributed systems, data engineering, AI & agentic systems, DevOps/SRE. Depth in few areas; breadth across, and appreciation for trade-offs in context.

You’ll thrive here if

• You reach for the simplest solution that gets the job done and distrust accidental complexity.
• You think in systems, not isolated parts.
• You stay calm when the path is unclear and build clarity for those around you.
• You move easily between the org-level picture and the technical detail.
• You're curious by default and pick up new domains fast.
• You’d rather be in the room with a customer solving a real problem.

What we’re looking for

• Demonstrable building software systems in complex environments.
• Strong engineering fundamentals; expert in at least one language, ideally polyglot.
• Hands‑on experience designing and delivering distributed systems at scale.
• Deep grasp of architecture, system design, and engineering trade-offs.
• Direct experience working with customers and business stakeholders.

What will you experience in terms of culture at Sahaj?

• A culture of trust, respect and transparency
• Opportunity to collaborate with some of the finest minds in the industry
• Work across multiple domains

What are the benefits of being at Sahaj?

• Unlimited leaves
• Life insurance & private health insurance
• No hierarchy
• Open Salaries