Hi, my name is Klaus Breyer.

Klaus Breyer

I am a CTO and Startup Founder/Advisor, living in Berlin.

I started the social media agency buddybrand and the Influencer Marketing Software BuzzBird some time ago.

Currently I am fighting climate change, by working on how Software Engineers can understand and reduce their co2 footprint and I plan to start a slow business in this area.


I build full stack products by myself and also lead whole teams with the responsibility for product and technology.

For startups in the scaling phase, I am available as an advisory board member or as interim CTO.

I am a mentor and coach to Software Engineers and first time startup founders.

I do not only build software – I take ownership: For business model, product and technology.


When building stuff by myself, I prefer serverless with NodeJS, supplemented by JAM Stack (vanilla Javascript / react / material ui). But I am also experienced with PHP (WordPress / Symfony) and Ruby on Rails in Production.

My Stack is optimized for fast prototyping / goto market while having a lot of experience with the integration of other services: Facebook Graph API (Insights, Pages, .. – I even wrote a book about it!), Instagram Analytics API, YouTube Analytics API, Twitter API, Github API, Sign in with Google, Stripe, Paddle, Firebase – and of course AWS: IOT Core, SQS, SNS, RDS, s3, STS, IAM, SES, Route53, Cloudwatch, Cloudfront, Elastic Beanstalk & Cloudformation.


10 Years of experience as a CTO in the areas of Consulting / Agency / SaaS / B2B / B2C / E-Commerce / Apps.

  • Software engineering background before going into digital marketing
  • Leadership of technical and product teams
  • Owner of companies technical vision & software architecture
  • Building ecosystems and APIs while being an evangelist for them.
  • Fostering an innovation culture & continuous improvement of developer tools for  productivity (especially for remote teams) 
  • Managing director for bootstrapped and venture backed companies.
  • Relentless lean approach on business strategy & product leadership



  • 2019 – Now: Member of the Advisory Board at touch361, a company for Customer Experience Management with a business intelligence SaaS for marketing touchpoint analysis.
  • 2018 – Now: Member of the Advisory Board at vitalfunktion GmbH, offering B2C and B2B solutions in the area of pharma.
  • 2018 – 2019: Founder and Chief Prototyping Officer of the B2C E-Commerce Startup Fotando GmbH, pursuing the ambitious goal of massively disrupting the mobile customer journey for photo printing (from hand to wall!). 
  • 2016 – 2018 Founder and Chief Technology Officer of influencer marketing SaaS BuzzBird GmbH (venture backed, 25 FTE), connecting brands and influencers for advertising campaigns through an machine learning based matching algorithm. 
  • 2010 – 2015: Founder and Managing Director Technology of the social media agency buddybrand GmbH (bootstrapped, 40 FTE), Germany’s first Facebook agency, which has evolved into a full service digital creative agency.


  • 2019 – Now: Technology Principal for Ray Sono AG, building a IIoT Applications.
  • 2016 – Now: Technical Evangelist for Native Studios UG, transforming the market for mobile user generated video content. 


Open source


Good software is always used but never finished.

The goal is to always build the next v01. In software and in life. Zen philosophy puts it like: Nothing exists in its present form or color except in this moment. A beginners mind is free of any possessions, as it knows that all is in a state of fluid change.