# Berk D. Demir

> Cryptography Infra at Meta

Location: Menlo Park, California, United States
Profile: https://flows.cv/berkddemir

## Work Experience
### Principal Engineer @ Meta
Jan 2016 – Present | Menlo Park, California, United States
Cryptography infrastructure.

Previously:
– Authentication, authorization, and use of cryptography.
– Web Foundation: facebook.com availability and resiliency
– Traffic Foundation: global scale optimal service delivery

### Sr Staff Site Reliability Engineer @ Twitter
Jan 2012 – Jan 2016 | San Francisco, California, United States
Availability, performance, and reliability.
Complex Incident Response.
Traffic Engineering.

### Systems Engineer @ CloudFlare, Inc.
Jan 2012 – Jan 2012 | San Francisco, California, United States

### Software Architect @ StumbleUpon
Jan 2009 – Jan 2012 | San Francisco, California, United States
Availability, latency and security.

• Infrastructural Components
- Near real time MySQL to HBase replication. (Java)
- ZooKeeper based service discovery. (Python)
- Kafka based messaging system with an HTTP gateway. (Scala)
- Content addressable storage for binary large objects on top of HBase used as a CDN origin. (Scala)
- K-ordered, multi datacenter capable, distributed ID generator. (Scala)
- Time series collectors for kernel, JVM, SNMP, and proprietary APIs of appliances. (C, Python)

• Service Delivery
- Frontend serving, caching and load balancing.
- TLS termination.

• Networking
- Data center networking.
- Move from Layer 2 (VLANs) to Layer 3 (IP) leaf and spine with OSPF in the core.
- Diversifying upstream connectivity by becoming multi-homed and establishing MLPEs with BGP at the border.
- OpenBSD based packet filtering and direct server return load balancing.

• Advisory Engineer
- OpenTSDB: An open source, scalable, high performance time series database built on top of HBase and written with Java.
- An N+2 system to serve StumbleUpon badges (around 70% of the all HTTP requests StumbleUpon gets) with very low latency and high availability. Written with Scala.

### Solution Architect (Integration, Scalability, Security) @ Meteksan Sistem
Jan 2005 – Jan 2009 | Ankara, Türkiye
• Scalability
­  - Bottleneck analysis and refactoring of Java, .NET, and LAMP stack applications.
­  - RDBMS performance work for MySQL and Oracle via engine tuning, sharding, and query refactoring.
­  - Migration of aging conventional OLAP systems to Hadoop and HBase.
­  - Anycast CDNs

• Integration
­  - Peddler of Service Oriented Architecture. SOAP, XML-RPC, and RESTful web services.
­  - Enterprise Service Buses with Oracle Fusion, BEA AquaLogic and Apache ServiceMix.
­  - Message Queue, Business Process Mgmt. and Data Services Platform integrations to ESB.

• Security
­  - Security engineer for software product line and customer proprietary information security projects.
­  - Black box and white box vulnerability assessment, penetration testing, and audit automation.
­  - MSSP operations lead for homeland security, law enforcement, and finance sector customers.

• Business Continuity and Disaster Recovery Planning & Compliance (2006-2007)
­  - BCP and DRP for government information systems.
­  - ISMS auditor for ISO 27000 and PCI-DSS.

• Product Development (2004-2006)
­  - DDoS Mitigation Appliances, Load Balancers with SSL offload.
  - Kernel development for OpenBSD based network security appliances.

### Internet Systems Engineer @ Meteksan Net
Jan 2003 – Jan 2005 | Ankara, Türkiye
• Planning, deployment and administration of large scale Internet services in an ISP environment.
  - Operations on OpenBSD, Solaris, and Linux based systems.
  - Veritas and Red Hat Cluster Server based high availability clusters.

• Planning, deployment, and administration of customer premises network security devices.
  - Checkpoint, OpenBSD, and Linux based firewall, VPN, and detection systems.
  - Design and implementation of OpenBSD and Linux based embedded security appliances.

• Web services for ISP infrastructure management and monitoring.
  - XML-RPC and SOAP services implemented in C and Python.

• Integration of open source software to create high performance, scalable Internet services.

### Systems and Security Consultant @ Self-employed
Jan 1999 – Jan 2003 | Ankara, Türkiye
• Contract agent with Andersen Consulting.
• Enterprise risk assessments, penetration tests, incident handling, computer forensics.
• Unix migrations. HPC, and high availability clusters.

### Network and UNIX Systems Administrator @ birNET Information Systems Ltd.
Jan 1996 – Jan 1999 | Ankara, Türkiye
• Day-to-day administration of ISP services on Unix and Windows NT based systems.
• Technical support for WAN connectivity with Cisco and Nokia network active devices.
• End-user technical support for dial-up customers.


## Education
### M.Sc. Candidate in Software Engineering
Orta Doğu Teknik Üniversitesi / Middle East Technical University

### B. Sc. in Computer Engineering
Baskent University

### B. Sc. in Electrical and Electronics Engineering
Baskent University


## Contact & Social
- LinkedIn: https://linkedin.com/in/bddemir
- Portfolio: https://bdd.fi

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Source: https://flows.cv/berkddemir
JSON Resume: https://flows.cv/berkddemir/resume.json
Last updated: 2026-04-12