Cloud Efficiency Engineer (AWS/FinOps)

About the role

About Buildkite

Buildkite's CI platform is trusted by the world's leading engineering teams, helping ship software used by more than 1 billion people every day. Companies including Canva, Meta, Mistral AI, and NVIDIA rely on Buildkite to run builds, tests, and deployments on their infrastructure, ours, or both — giving them the speed, reliability, and flexibility to ship with confidence.

About the Role

Every build, test, and deployment our customers run costs us something. Right now we can see the top-line number — our AWS and Datadog spend — and we can see revenue. What we can't see clearly enough is the line between them: which operations drive our cost of goods sold, how that changes as customers scale, and which changes would move it. If you’ve been in a similar role but have been frustrated by not being able to go super deep on this and model different categories/scenarios and costs then you’ll be able to scratch that itch here.

Cost questions arrive from the exec team as business questions, and today the answers get assembled part-time by people whose main job is something else. This role is designed to close this gap.

This is a hands-on engineering role, not a reporting one: you'll own Buildkite's cloud efficiency picture end to end — tracing COGS signals down to the tight loop technical drivers that cause them, building the models that explain them, then shipping or driving the changes that bring them down, and proving afterwards that the saving actually landed. You'll report to the VP Engineering Platform and pair closely with him for your first month or two before running with substantial autonomy.

You'll also partner with our CTO, Platform engineering, with the Data team who own the canonical COGS model, and with Finance on the FinOps side. The constraint that makes this interesting is that none of this work can come at the expense of reliability, throughput, or customer experience. Ultimately this role will help us with cost optimisation and directly driving growth through technical efficiency.

Cutting the bill is easy. But cutting the bill without anyone noticing except the CFO is basically the crux of the job.

What You'll Do

Follow the money

- Trace cost signals to their technical causes — down to customer-level job costs & state machine changes, GraphQL cost by function, and per-operation unit economics — rather than stopping at service-level totals.

- Build and maintain cost models for our most common and most expensive operations, so that when the shape of our traffic changes, we can explain what it does to our margin before the invoice arrives.

- Rank the opportunities into a defensible portfolio: expected saving, risk, effort, and who has to be involved.

Ship the fix

- Implement safe, measurable optimisations yourself where the change sits in code or configuration you can own.

- Partner with the engineering teams who own affected systems on the larger work, bringing them evidence rather than an edict.