Senior Backend Software Engineer (APIs)

Posting Open Date: 08/24/2026

Senior Backend Software Engineer (APIs), Security Products

Some of the largest sites on the internet trust Fastly to keep them safe. The Security Products Console team owns the public-facing interface they use to do it - configuring Next-Gen WAF, DDoS protection, Bot Management, and the products we're building next.

Our APIs meet critical business needs. Customers deploy them during active attacks, automate them through Terraform and CI/CD, and build entire security workflows on top of them. When the threat landscape moves, our APIs are how customers move with it. A bad release here leaves them exposed when they need us most: a great one is invisible, and that's the bar.

We're hiring as the API surface scales for new product launches and a growing developer ecosystem. You'll be one of the engineers shaping what that surface looks like for the next several years.

What You'll Do:

• Design, ship, and own public-facing APIs and backend services in Go -from technical proposal & design docs through implementation, testing, and production rollout and on-call support.
• Use AI coding agents as part of your daily workflow.
• Partner with frontend engineers, product managers, and security researchers to ship the customer experience end-to-end.
• Take ambiguous or broadly-scoped problems and turn them into well-defined technical plans that the team can execute on.
• Author design and architectural documents and use them to drive alignment across engineering and product teams
• Collaborate with internal platform teams, product managers, and stakeholders across the organization to understand their needs and deliver impactful solutions
• Consider stability, performance, and scalability in your designs and in the guidance you provide to the team
• Mentor and grow other engineers on the team through code review, pairing, and technical leadership
• Participate in an on-call rotation

What We're Looking For:

• Hands-on experience designing and building reliable, large-scale backend systems - most Senior Engineers at Fastly have at least 5 years of relevant experience
• 5+ years shipping production Go as your primary language.
• 3+ years on public APIs with external consumers. You've shipped a breaking change to customers who'd already integrated against your API. You've written a deprecation notice that actually went out.
• You drive projects, not just tasks. You've owned a multi-week effort end-to-end: design doc through post-launch.
• Good judgement on RESTful API design: resource modeling, versioning, idempotency, error semantics, pagination, OpenAPI. You've made one of these calls wrong in production and remember what it cost to clean up.
• You design for the people downstream of your API. The customer hitting your endpoint at 3am, the support engineer debugging their escalation, the frontend teammate integrating against your contract. You've watched a vague error message of yours confuse someone and changed how you write them since
• Testing and observability as subtraction, not addition. You can name a metric you added that paid off — and one you'd delete now.
• Coding agents as a daily driver, not reluctantly. This team uses them heavily

• Built or operated security products (WAF, bot, DDoS, app security).
• Working knowledge of auth at API scale (RBAC, OAuth, JWT, SAML)

Work Hours:

• This position will require you to be available during core business hours (Pacific Time) and occasional nights and weekends as required for on call support

Work Location(s) & Travel Requirements:

This position is open to the following preferred office locations:

• San Francisco, CA, USA
• Denver, CO, USA

There is a strong preference for Hybrid near a local office. However, we may be willing to consider exceptionally qualified remote candidates within US Pacific and Mountain time zones.

Salary:

The estimated salary range for this position is $181,220 - $217,464

We offer a comprehensive benefits package including medical, dental, and vision insurance. Family planning, mental health support along with Employee Assistance Program, Insurance (Life, Disability, and Accident), a Flexible Vacation policy and up to 18 days of accrued paid sick leave are there to help support our employees. We also offer 401(k) (including company match) and an Employee Stock Purchase Program. For 2026, we offer 11 paid local holidays, 12 paid company wellness days.