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🐍 Email Security Gateway Engineer | Python | SaaS | AI (πŸ“Remote - with flexible hours)

Published on 12 of May of 2026

Madrid

Published on 12 of May of 2026
Location
Madrid
Category
IT and telecommunications
Category
Programming
Sector
Programming, consulting and other computing activities
working day
Full Time
Modality
Remote work
Professional level
Employee
Department
Engineering

Description

🌍 Remote Worldwide | πŸ•’ Full-time | πŸ—£οΈ Fluent English

πŸ‘‰ Are you driven by building robust cybersecurity architectures implemented with the versatility of Python/Django and the algorithmic intelligence of AI?

πŸ‘‰ Do you want to work at the intersection of AI, cybersecurity, and SaaS, within the startup ecosystem of Google, AWS, Nvidia, and CrowdStrike?

πŸ‘‰ Are you looking to grow fast in a high-impact role where you can take ownership of AI initiatives from the ground up in a Google-backed startup?

This is your opportunity. Build the future of cybersecurity with us.

At Zepo, we are building an AI-powered cybersecurity SaaS platform that protects thousands of users from real-time threats. Your main mission will be to lead the technical development of our new security platform, a critical tool designed to defend thousands of people against cyber threats in real-time.

We are a team of 50+ people, recently backed by a $15M funding round and selected by Google for Startups. We are looking for a Senior Python Engineer specialized in email security Gateway who wants to scale our architecture for the future.

The role

We are looking for a Senior Software Engineer specializing in Python to lead the development and architecture of our Email Security Gateway. Your mission will be to build the core of our email processing engine, ensuring a high-availability architecture capable of analyzing, filtering, and neutralizing threats (phishing, malware, spear-phishing) in real-time, before they reach the end user's inbox.

As part of our engineering team, you won't just be writing code; you will be defining how our platform processes billions of emails under the highest standards of security, speed, and precision.

What You'll Do (Responsibilities)

  • Core Gateway Development: Architect and build the email processing engine using Python, ensuring ultra-low latency and high throughput capacity.
  • Email Protocol Management: Implement advanced logic for protocol handling (SMTP, IMAP, MIME parsing) and email authentication (SPF, DKIM, DMARC).
  • AI Integration: Develop pipelines that connect our email flow with our ML models, enabling real-time decision-making regarding message security.
  • Scalability and High Availability: Design resilient systems capable of handling traffic spikes without compromising email delivery, utilizing asynchronous programming (asyncio, FastAPI) and Celery to manage complex, distributed background task processing.
  • Security by Design: Ensure the system is not only fast but intrinsically secure, implementing load testing, static analysis, and robust cloud deployments.

Your benefits of leveling up at Zepo

  • ✨ Work flexibility: Remote work worldwide, with access to one of the most exciting office spaces in the city, events, and networking opportunities in our HQ in Madrid.
  • πŸ“š Professional development: Participate in advanced programs with Google for Startups, with direct access to experts from the Google ecosystem and top-tier tech partners.
  • 🌍 Direct impact: Build AI-driven solutions that protect thousands of companies and employees.
  • 🀝 Open and collaborative culture: A growing startup where ideas matter and ownership is real.
  • πŸ”₯ High-impact projects: Lead AI initiatives in a platform recognized internationally for innovation in cybersecurity.
  • πŸ’΅ Flexible Compensation: Tax-free benefits via Cobee, including childcare vouchers, transport passes, and meal tickets.
  • πŸ’° Competitive compensation: Attractive salary + potential performance-based incentives.

Minimum requirements

What We're Looking For

  • Solid Experience: 5–8+ years in Backend development, distributed systems, or high-performance architecture. You have a proven track record of building systems that handle large volumes of data in real-time.
  • Python Mastery & Task Queues: Advanced command of Python and asynchronous frameworks (e.g., FastAPI, asyncio) to build high-concurrency processing engines. Deep experience with Celery for distributed task management, monitoring, and scaling asynchronous workflows is essential.
  • Email Integration Expert: Hands-on experience integrating solutions with email providers (Google Workspace, Microsoft 365, Exchange). You have a deep understanding of routing management (SMTP Relay, Journaling), resolving MIME header conflicts, and ensuring compatibility between our platform and customer infrastructure.
  • Protocol and Security Domain: Deep knowledge of the email technology stack (SMTP, IMAP, MIME parsing) and authentication standards (SPF, DKIM, DMARC).
  • Data Architecture & AI: Experience implementing processing pipelines where AI/ML is integrated into the data flow. You know how to build inference systems that make millisecond-level decisions on whether an email is a threat.
  • Engineering Culture: Experience managing the Software Development Life Cycle (SDLC) with a focus on critical systems, versioning, and zero-downtime deployments.
  • Rigorous Testing Culture: Proven experience in Unit Testing, Load Testing, and attack simulations.
  • Technical Analysis: Ability to translate RFCs, complex technical documentation, and threat intelligence reports into clean, scalable, and automated code.
  • Professional English: Full fluency, as you will collaborate in an international environment.

πŸ”Ή Nice to have

  • Authentication Protocols: Expertise in OAuth2, OpenID Connect, and SAML.
  • Cloud & API Integrations: Hands-on experience with Microsoft Azure, Microsoft Graph API, and Google APIs.
  • Messaging & Transport Systems: Integration experience with Email (Transport Rules), SMS, Slack, and Microsoft Teams.
  • Experience in high-growth startups or building proprietary SaaS products.More about Zepo

More About Zepo.

πŸ“Ή https://youtu.be/4m7c_hHO9Gs

πŸ’Ž https://zepo.ai/blog/zepo-raises-15m-seed-round-agentic-social-intelligence

πŸš€ Meet the team: https://zepo.ai/

Join Zepo and lead AI innovation in a cybersecurity platform that protects companies and people from digital threats.

We’re really looking forward to meeting you! πŸš€

Legal notice

The personal data provided in your application and during the recruitment process will be processed by Zepo Intelligence, S.L. (β€œZepo”), acting as Data Controller. By submitting your CV, you consent to the processing of your personal data for the purpose of evaluating and selecting you as a candidate for the position. Your personal data will be treated confidentially and will only be used for the recruitment process related to the selected job offer.

Regarding the data retention period, your personal data will be deleted after three months of inactivity, in compliance with GDPR and applicable data protection regulations.

If you wish to exercise your rights of access, rectification, erasure, portability, or objection regarding your personal data, you may do so by contacting contact@zepo.app, in accordance with GDPR.

For more information, please visit: https://zepo.ai/privacy-policy

By submitting your application, you confirm that you have read and understood this notice and agree to the processing of your personal data as described above.