---
title: 'AppSec - Vulnerability Management Engineer at Trendyol'
canonical: 'https://feeny.ai/job/appsec-vulnerability-management-engineer-trendyol-istanbul-1e3tsr510a2q'
type: 'job'
last_seen: '2026-09-10'
---

# AppSec - Vulnerability Management Engineer at Trendyol

- **Company:** Trendyol
- **Location:** Istanbul, Turkey / Maslak
- **Employment:** full-time
- **Work type:** hybrid
- **Posted:** 2023-06-20
- **Last confirmed live:** 2026-09-10
- **Apply:** https://jobs.lever.co/trendyol/aaf3bc42-3153-4875-997c-ab85561ad411

## Job description

## ABOUT THE TEAM

We’re shaping the future of financial technology at Trendyol. As Trendyol’s technology teams, we’re not only building for today we’re designing the financial experiences of tomorrow. From payment infrastructure and digital wallets to smart credit systems and personalized financial services, we create solutions that empower millions of users across our ecosystem. With Trendyol Pay, we enable fast, secure, and seamless payment journeys. Through Trendyol Finance, we develop inclusive and accessible products that simplify financial decisions.

We are united by a shared purpose:To create a positive impact in our ecosystem by enabling commerce through technology

## About the Role

As an Application Security Engineer, you’ll work closely with Trendyol’s engineering teams to enhance application security across our platforms. You’ll perform web and mobile security testing, validate fixes through code reviews, and provide expert guidance on secure coding practices. In this role, you’ll support our bug bounty program, develop custom security tools, and help drive root-cause analysis and remediation. We’re looking for a collaborative, open-minded teammate who is eager to improve, communicate clearly, and promote security best practices throughout the organization.

Your Main Responsibilities:

- Ability to work collaboratively in a team environment and is a friendly, humble, responsible teammate.
- Be a subject matter expert and guidance to Trendyol Engineering for secure coding practices, application security.
- Experience in performing web security testing on web applications and mobile applications.
- Ensuring to confirm of the fix of the vulnerability by making manual code review on the relevant commit.
- Experience identifying and protecting against web application and web-service security vulnerabilities including those found in the OWASP Top 10.
- Experience in fixing vulnerabilities, documenting and remediation guidance for discovered vulnerabilities.
- Developing custom security tools and security rules(e.g. Semgrep / Nuclei)
- Promoting security best practices among developers.
- Ability to conduct root cause analysis against vulnerabilities and determine feasible technical solutions.
- Managing Bug Bounty Platform.

Qualities We Are Looking For:

- Experience with multiple programming/scripting languages (such as, Java, Golang, Python etc.)
- Having excellent communication skills.
- Experience with vulnerability management and enterprise remediation efforts.
- Being an Agile minded team player.
- Eagerness on self-improvement, open-minded, future-oriented.
- English language skills for reading technical documentation and to fix the vulnerabilities with international developers.
- Professional certification (e.g. eWPT, eWPTXv2, OSWE, eMAPT, GWAPT) preferred.
- Familiarity with front-end and back-end web application frameworks (i.e. Spring, Gin, React, etc).
- Bonus points for community contributions like public CVEs, bug bounty recognition, blogs, etc.

## What We Offer

A hybrid working model with flexibility — a schedule that helps you find the right balance between flexibility and team bonding, including work-from-abroad opportunities and a summer working model. A customizable FlexBenefits budget — Adjust your daily meal allowance, choose your health insurance package (and extend it to your spouse or children), and pick from additional benefits like fuel support or Trendyol shopping credits. Comprehensive wellbeing support — Take advantage of our extended health package, which includes annual mini health screenings, access to location-based in-house doctors, psychologist and dietitian support, and HPV vaccination coverage. Personalized training allowance and learning opportunities — Use your annual budget for any training or conference of your choice, explore our Learning Management System (LMS) anytime, and join in-person learning sessions offered throughout the year. Responsibility from day one — Take full ownership from the start in a culture where every voice is heard and valued. A diverse, international team — Collaborate with global peers across our offices in Berlin, Amsterdam, Dubai, and beyond, in a startup-spirited and collaborative environment. Opportunities to grow with the best — Tackle meaningful challenges, develop through hands-on experience, and grow with the support of expert guidance and global mentoring. Meaningful connections beyond tasks — Be part of team rituals, events, and social activities that help us stay connected and inspired.

Take the Next Step If this role excites you, apply now and let’s take the next step together. Want to get to know the team better first? Explore our Career Website, LinkedIn, or YouTube to learn more about #LifeatTrendyol and how we work.

## About Trendyol

## Company Overview
- **One-liner**: Trendyol is Turkey's leading e-commerce platform and a top EMEA player, operating a tech-driven ecosystem that connects customers, sellers, payments, and delivery across 35 countries.
- **Entity Type**: Private (decacorn; 70% owned by Alibaba Group)
- **Headquarters**: Istanbul, Turkey (Maslak Campus, Spine Tower)
- **Founded**: 2010
- **Founders**: Demet Mutlu, Evren Üçok, Begüm Tekin

## Core Business
- **Primary industry**: E-commerce / Online marketplace (with integrated logistics, fintech, and technology services)
- **Target customers**: B2C (consumers) and B2B/B2B2C (sellers, local manufacturers, brands)
- **Mission or purpose**: To provide customers globally with a seamless e-commerce experience, while enabling the digital transformation of hundreds of thousands of sellers and supporting inclusion in the digital economy — including women entrepreneurs.

## Products & Services
- **Trendyol Marketplace**: The core e-commerce platform offering fashion, electronics, home goods, and more to ~40 million customers, with 2.5+ million packages delivered daily.
- **Trendyol Tech**: One of the region's leading R&D hubs, powering AI-driven recommendations, data capabilities, and marketplace infrastructure.
- **Trendyol Express**: A fast-growing in-house delivery network handling first-mile and last-mile logistics.
- **Dolap**: The largest second-hand goods platform in the region, integrated into the Trendyol ecosystem.
- **Trendyol Fintech**: Payments and embedded financial services arm supporting transactions within the ecosystem.
- **Trendyol Go (by Uber Eats)**: On-demand delivery service (noted in alumni talent flows; part of the broader ecosystem).

## Market Standing
- **Valuation/Market Cap**: Decacorn status (valued at over $10B; exact figure not publicly disclosed). Backed by Alibaba Group, General Atlantic, SoftBank Vision Fund, Princeville Capital, and leading sovereign wealth funds.
- **Key Metric**: Annual Revenue: **$2.5B** (reported); Total Funding: **$1.89B** across 5+ rounds, including a $1.5B private equity round in August 2021 led by General Atlantic and SoftBank Vision Fund.
- **Notable Investors/Partners**: Alibaba Group (majority owner, ~70%), General Atlantic, SoftBank Vision Fund, Tiger Global Management, Kleiner Perkins, Princeville Capital.
- **Growth Signals**:
  - Headcount grew **+12.4% YoY** to 5,973 employees; active job postings up **+100% YoY**.
  - International expansion across Gulf and Central & Eastern Europe; now serves **10M+ international customers** (Romania, KSA, UAE, Germany, Netherlands, and more).
  - Workforce distributed across **30 countries**.
  - Ecosystem expansion into fintech and second-hand marketplace (Dolap).

## Competitive Advantages
- **Alibaba backing**: Strategic ownership provides capital, supply chain expertise, and global best practices.
- **Integrated ecosystem**: Unlike pure-play marketplaces, Trendyol owns its tech R&D, logistics network (Trendyol Express), fintech arm, and second-hand platform — creating strong lock-in across the value chain.
- **Scale and data moat**: 40M customers, 2.5M+ daily packages, and AI-driven systems generate compounding data advantages for personalization and seller tools.
- **Regional dominance**: The leading e-commerce platform in Turkey, a top player across EMEA, with deep local seller/manufacturer relationships.

## Strategic Focus
- **International expansion**: Growing aggressively in the Gulf region (especially Saudi Arabia) and Central & Eastern Europe (Romania and beyond).
- **Fintech growth**: Expanding payments and embedded financial services within the ecosystem.
- **Sustainability**: Executing the Trendyol Sustainable Impact Plan focused on responsible growth, people, and planet.
- **Seller empowerment**: Continuing digital transformation for hundreds of thousands of sellers, including support for women entrepreneurs.

## Why Work Here
- **Culture**: Values include "Customer First," "Stronger as a Team" (#OneDreamOneTeam), "Always Sincere and Humble," "Strive to Be Better Every Day," "Results Matter," and "Trust in Data." The company describes itself as having a startup spirit with open communication and constructive feedback.
- **Work environment**: Hybrid work arrangements (e.g., hybrid roles in Bucharest and Istanbul); flexible work policies; a young, diverse team — average age 32, with 35+ nationalities represented.
- **Growth & development**: Comprehensive onboarding, diverse learning programs, rotation opportunities, and early empowerment/ownership for new hires.
- **Scale with startup energy**: Opportunity to work on tech challenges at massive scale (2.5M+ daily packages, AI systems, logistics tech) while maintaining an agile, dynamic culture.
- **Engineering & technical team**: ~1,600 technical employees (14% of workforce); strong talent pipeline from companies like Hepsiburada, Amazon, Turkcell, and Getir.

## Sources
1. [careers.trendyol.com](https://careers.trendyol.com/)
2. [careers.trendyol.com - Life At Trendyol](https://careers.trendyol.com/life-at-trendyol)
3. [careers.trendyol.com - Culture](https://careers.trendyol.com/culture)
4. [jobs.lever.co/trendyol](https://jobs.lever.co/trendyol)
5. [linkedin.com/company/trendyolgroup](https://linkedin.com/company/trendyolgroup)

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