Security Engineer, StackOne
+ Meaningful share options (EMI)
2 days a week in office
Integration infrastructure for AI agents
Be an early applicant
Integration infrastructure for AI agents
21-100 employees
Be an early applicant
+ Meaningful share options (EMI)
2 days a week in office
21-100 employees
Company mission
To build the integration infrastructure that lets AI agents act — securely, reliably, across any system.
Role
Who you are
- 3+ years in security engineering with hands-on AWS security: IAM, KMS, networking, secrets, GuardDuty / Security Hub
- Strong coding ability in TypeScript or Python — comfortable shipping production code, not just configs and scripts
- Application security fluency: OWASP Top 10, threat modeling, and code-level reviews on real systems
- Experience securing a B2B SaaS multi-tenant production environment
- Comfort owning end-to-end work: scope, ship, measure. You don’t wait for a queue
- Clear communication with engineers, product, and non-technical stakeholders
- Bias toward automating security checks instead of running manual checklists
- (Preferred) Experience with Aikido, Drata, Cloudflare Workers, or pen testing in a compliance-mature environment
What the job involves
- We’re looking for a Security Engineer to be a key hire on our Engineering team and own our cloud and product security posture as we scale. You’ll work across our AWS and Cloudflare estate, harden our secure SDLC, run pen testing efforts end-to-end, and threat-model the features powering our connectors, OAuth flows, and agent execution paths
- It’s a hands-on, DevSecOps-heavy role: you write code, ship tooling, and embed security into how engineers work every day. You’ll report directly to the CTO and have broad scope across the platform — from CI/CD pipelines to multi-tenant APIs to incident response on authentication flows
- Own the secure SDLC: drive SAST, dependency scanning, secrets detection, and PR-blocking standards across every repository
- Harden our AWS and Cloudflare estate: IAM, secrets, network segmentation, KMS, WAF, GuardDuty, and zero-trust patterns
- Run pen testing end-to-end: scope and coordinate engagements with both AI-driven scanners and human researchers, then drive findings through fix and retest
- Threat-model product features before they ship — OAuth flows, multi-tenant APIs, connector executions, and agent tool-calling paths
- Build detection and response capability around credential and authentication flows, with observability that closes incidents fast
- Partner with engineering to raise the bar day-to-day: architecture reviews, written standards, and security embedded in code review
- Use LLMs and agents to accelerate security workflows (triage, code review, evidence gathering) with guardrails you trust
- Support compliance work where it intersects security engineering: SOC 2, ISO 27001, customer security reviews, and pen test responses
Salary benchmarks
Our take
The explosion of SaaS tools has created an integration nightmare for companies. More and more B2B customers are expecting their SaaS tools to integrate with each other natively. But building and managing API connections in-house as a software vendor is time-consuming and costly, diverting teams from their core roadmap and stopping sales teams from selling.
As the next-generation integration platform, StackOne is solving the challenge of building SaaS integrations at scale once and for all. Founded in 2023 by ex-Google and Oracle executives, StackOne has seen exceptionally fast growth since its launch. With its best-in-class security and real-time architecture, the company is well-positioned to become a category leader in the API integration solutions market.
Steph
Company Specialist at Welcome to the Jungle
Company
Funding (last 2 of 3 rounds)
Apr 2025
$20m
Series A
Nov 2023
$3.6m
Seed
Total funding: $23.9m
Company benefits
- Meaningful share options (EMI) - share in the company's success as we grow
- 25 days holiday + 1 additional day per year of tenure
- Hybrid working friendly - typically 2 days/week in our London office. We’re open to discussing flexible arrangements—please share any preferences in your application
- Private health insurance - including dental & optical
- £15/day lunch budget when working from our London office, up to £120/month
- £1,000 for your home office set up + £500/year top-up
- Health, fitness and gift card discounts
- Cycle2Work and Electric Car Scheme
- Monthly in-person socials
- Annual team offsite to sunny spots (last ones were in Spain and Portugal!)
Company HQ
Central London
Articles
Leadership
Romain Sestier
(Co-Founder & CEO)Previously worked for Google as co-founder and Product Lead of Area120, VP of Product and Sales at Yieldify, co-founder and CEO of Upper.ai and Head of UK Professional Services at ContentSquare.
Guillaume Lebedel
(Co-Founder & CTO)Previously VP of Engineering at Yieldify until its acquisition by Epsilon/Publicis. Also co-founded another start-up and worked at Maxymiser (acq. by Oracle) as a developer.
Diversity, Equity & Inclusion at StackOne
Yasmin Chalmers (Head of People)
- Women @ StackOne community
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