Senior Software Engineer, Data and Platform

Senior Software Engineer, Data & Platform Every new customer adds 1,000 career pages to crawl daily, scaling to 1.5M a day by Series A. We're fixing a Google-scale problem, pointed at Staffing & Recruitment. Backed at seed by Reed, the £1BN UK Recruitment group. We need someone who loves building from the bottom up and can lead the team that follows. The problem Illumini crawls every career page and every hiring manager relationship in the world, and turns it into signal recruiters pay for. We are at £143K ARR and are targeting £1.8M+ ARR by March 2028. Between now and then, the fleet of career pages we crawl goes from thousands to millions, and the infra cost per licence has to come down while coverage holds at 95%+. The core problem is not building new features, it's onboarding licence after licence, holding coverage, and driving unit economics down as the system scales 10x to 100x. AI is part of how we build, from the crawl layer to the enrichment pipelines to the dev workflow itself. What you'll own

• The data acquisition engine, crawling, enrichment routing, orchestration, everything. Backend-leading development, minor frontend fixes.
• Coverage at 95%+ sustained, with the observability and resilience to hold it there through 10x to 100x volume
• Hiring manager coverage to 95%+, matching hiring managers to vacancies. 
• Infrastructure cost per licence, driving it down as volume goes up
• Incident response patterns, multi provider routing, reliability under load
• Team lead track. By month 6 to 8, if targets are hit, you hire and onboard engineer number two and start building the team under you  What you'll bring
• 5 to 8 years shipping production Python systems at Series A or B startups
• Strong AWS. Fargate or ECS, Lambda, DynamoDB, S3, CloudWatch
• Shipped data acquisition, crawling, or API integration at real scale
• Previously owned reliability of a customer facing system
• Experience driving infrastructure cost per customer down on live systems
• Comfortable using AI in your day to day. LLMs for code generation, agents for repetitive work, modern tooling where it saves time, you're not shipping anything you don't understand.
• Backend first, but happy to do simple frontend fixes when the business needs it
• Early-stage builder. You can take v1 code and shape it into the platform that scales, not just maintain what's there.
• Systems thinker, when you touch infra, you think about cascading effects
• Broad across the stack, crawling, data pipelines, distributed systems, cost engineering, whatever you've gone deep on. You can own crawling AND infra AND cost architecture, and you bring one of them to Staff level
• Commercial about engineering, you understand unit economics and business value Core stack: Python, FastAPI, AWS, Terraform, GitHub Actions, CloudWatch. A big plus: experience reducing infra cost per customer on live systems with real numbers to show. A bonus, not a must: Staffing & Recruitment, HR tech, or data licensing background. Why this role Illumini is backed at seed by Reed, the £1BN UK recruitment group. One technical founder today, team of five by June 2027, team of 20+ post Series A in March 2028. This is engineer number one, team lead track, the engine has been in production for 18 months. You take it from v1 to the platform that scales 100x into Series A. On target, by month 6 to 8 you hire engineer two & by Series A you're leading the team. Early equity pre-Series A at 0.5-1.5% means a meaningful payout upon exit. Compensation and logistics
• Salary £85,000 to £115,000
• 6% annual bonus
• Stock options 0.5 to 1.5%, 4 year vest, 1 year cliff
• 12 month comp refresh pre committed if targets are hit
• 25 days annual leave + UK bank holidays
• Hybrid, Tue to Thu in Liverpool Street office
• Pension, L&D budget, regular socials
• Full time, Permanent
• Reports to Founder How to apply Send your CV with one paragraph on the biggest volume-and-variability problem you have ever owned, where the inputs run into the millions, keep shifting shape, and the system has to hold. Email blynch@illumini-technology.io & expect a reply within 24 hours.