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Your Best Ally in Crypto Security Since 2017

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Mission & Key Concepts

Pessimistic has been working in blockchain security since 2017. We develop security tools, provide consultation to developers, and conduct audits of smart contracts for various blockchains.

Our clients include 1inch, Lido, Zerion, Morpho, Azuro, Opium, xDAO, Sweat Economy, and other top teams. We work with new code and fresh ideas every day. It's challenging, interesting, and provides powerful growth opportunities.

How We Can Help:

  • Consulting

Pre-production code and overall architecture recommendations. Get expert guidance right from the start, ensuring a solid security foundation for your project.

  • Auditing

A combination of manual and automated auditing processes. Benefit from a comprehensive audit approach, ensuring maximum security and reliability.

  • Retainer

A subscription-based service offering ongoing support. Rely on our continuous oversight and expertise at each phase of the process.

Why Pessimistic?

  • Tailored to you Top service appreciated by clients
  • Reliable Deadlines prioritised and met
  • Cost-effective – 90% time spent on code security

History & Achievements

1/ Founded: 2017

2/ HQ: Tallinn, Estonia

3/ Auditing:

  • 250,000+ Lines of code audited
  • 400+ Security Audits Delivered
  • 2,600+ Issues Found

Our Contributions To Blockchain Security

  • Open-Sourced Detectors

Pessimistic pioneered and keeps maintaining Slitherin, a set of essential vulnerability detectors. Built on the industry-standard framework Slither, it is a must-have for anyone serious about secure blockchain development.

  • Security Monitoring System

We developed Spotter, a cutting-edge monitoring system that detects potential exploits in their early stages, often before they even reach the blockchain. Stay one step ahead of hackers with Spotter.

  • Public Keynotes and research

We're not just about providing services; we're about advancing the field. We actively share our insights through research articles and public appearances, including keynotes at major events like ETH Barcelona, ETH Belgrade, and DeFi Security Summit.

Core Team

  • Alexander Seleznev – CEO
  • Evgeny Marchenko – CTO
  • Konstantin Zherebtsov – Business Development Lead


  • Work at the forefront of technology in one of the most cutting-edge fields
  • Remote work from anywhere in the world
  • Compensation in the currency of your choice, including crypto
  • A rapidly growing team with no legacy code
  • Competitive salary, bonuses, and regular updates
  • Conference ticket payment
  • Weekly internal research for the team
  • Audits 4 out of 5 working days a week. And one day for tasks on personal working goals