Senior Software Engineer (Database Reliability)
Confirmed on the employer's own hiring board on Nov 14, 2026. First seen by Alion on Sep 28, 2026. Capital on Tap scores A on the Alion truth index.
We’re Capital on Tap
Capital on Tap started because small businesses were underserved. Big banks were slow, their products weren't fit for purpose, and small business owners often couldn't access what they needed. We set out to fix that.
Today we're a financial platform - not just a credit card company. We offer a best-in-class business credit card, SME-focused spend management platform, a savings product that hit £1 billion in funds within its first year, and a growing suite of tools and financial products that make running a small business easier.
1,000+ employees, £20bn in annual card spend, 200,000+ customers, 17,000+ Trustpilot reviews averaging 4.7 stars, and we're profitable. We’ve done a pretty good job so far, but we’re just getting started!
This is a Hybrid role, the Database team work from our Moorgate (London) Offices 2 days per week.
The Role
Our platform runs on .NET and SQL Server on Azure, and it has scaled well beyond its original design parameters. We're hiring our first dedicated Database Software Engineer to own performance and scale: to make the fast paths faster, keep them ahead as volume grows, and give every engineer here the tooling and judgement to write data access that holds up in production.
You'll join a small, agile team of Database Engineers and SREs in a hands-on, senior individual contributor role. You won't be working a ticket queue. You'll choose the work that moves the needle on latency, cost and reliability, and you'll be trusted to call out what needs re-architecting.
What You'll Do
- Evangelise advanced database technologies to the software engineering teams. Research, demo and promote technologies such as graph databases, vector stores and zero-downtime data migrations, and how they can be used in C# via Entity Framework or other ORM technologies.
- Build and enhance self serve tooling to enable development teams to identify query plan regressions along with self service diagnostic tools to allow teams to debug their own query performance.
- Work alongside Product Engineering and our data analytics team, reviewing designs before they ship and levelling up how the whole engineering org thinks about data access.
- Own performance across our transactional SQL Server estate, using execution plans, Query Store, wait statistics, real production telemetry and other data-driven measures.
- Investigate and implement scaling techniques such as multi-cluster architecture, contained availability groups, sharding, etc, to ensure Capital on Tap’s distributed software estate can continue to support a fast growing customer base and increasing service count.
What We're Looking For
- Experience working with ORMs (ideally Entity Framework) and the particular performance tradeoffs that come with an ORM.
- Experience with programming in C# /.NET.
- Substantial experience running Microsoft SQL Server in production at scale, whether that be self managed, Managed Instances, or on Azure SQL, in a business where downtime and latency have direct commercial impact.
- Real depth in the internals. The query optimiser and plan cache, indexing and statistics, locking, blocking and isolation levels, tempdb, and the wait types that tell you which of those is actually hurting you.
- A track record of specific, measurable performance wins you can walk us through end to end.
- Experience scaling relational data past the point where tuning alone works. Partitioning, archival, denormalisation, caching, read replicas, or a considered move to a different store.
- Comfortable writing application code, not just scripts. T-SQL to an expert level, plus PowerShell, and infrastructure as code.
- Hands-on with HA/DR design and with leading production incidents.
- An ability to translate technical concepts and trade-offs to non-database specialists.
Suggested Interview Process
- 30 minute screening with a Talent Partner.
- 60 minute tech chat with Hiring Manager
- 90 minute technical interview with 2 team members
- 30 minute values interview with Head of Platform Engineering
Diversity & Inclusion
We welcome, consider and encourage applications from anyone who shares our commitment to inclusivity. Join us in creating a space where authenticity thrives, and everyone can do their best work.
Great Work Deserves Great Perks
We try not to take ourselves too seriously (all the time) so we make sure our office is decked out with a pool table, arcade machine, beer tap, and a couple of office dogs thrown in for good measure. Check out our benefits:
Private Healthcare including dental and opticians services through Vitality
Worldwide travel insurance through Vitality
Anniversary Rewards (£250, £500, £750, 4-week fully paid sabbatical)
Salary Sacrifice Pension Scheme up to 7% match
Octopus EV Salary Sacrifice Scheme
28 days holiday (plus bank holidays)
Annual Learning and Wellbeing Budget
Enhanced Parental Leave
Cycle to Work Scheme
Season Ticket Loan
6 free therapy sessions per year
Dog Friendly Offices
Free drinks and snacks in our offices
Check out more of our benefits, values and missionhere.
Other Info
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Email [email protected] if you have any questions.
Excited to work here? Apply!
If you’d like to progress your career within our fast growing, profitable fintech then click apply and we will aim to get back to you within 3 working days (during busy periods this could take up to 5 working days.)