1. JavaScript

Amsterdam JS is a strong and all-embracing JavaScript community, since 2010. Covers everything JavaScript, from the browser to the server, from the framework to the crazy hack and from the hardware appliance to the data visualization.  

https://www.meetup.com/AmsterdamJS/

2. HTML and CSS

HTML and CSS is a group for all web enthusiasts with a focus on HTML, CSS and Javascript, to share knowledge and meet people with similar interests.

https://www.meetup.com/Amsterdam-HTML-CSS/

3. Android

The Dutch Android User Group organises fun and technical meetups with presentations done by Android gurus, open discussions, demo's and workshops. The Meetup where Android professionals can learn more about the Android technology.

https://www.meetup.com/dutch-aug/

4. Python

Amsterdam Python is a group for those interested in Python, Django, cloud computing, deployment, provisioning, virtualization and related technologies. Meetups held in and around Amsterdam, including the HQ of hostingcompany Byte.

https://www.meetup.com/Amsterdam-Python-Meetup-Group/

5. PHP

An English-speaking user group for PHP Developers in and around Amsterdam. Always looking for new developers to spread knowledge and resources.

https://www.meetup.com/AmsterdamPHP/

6. DevOps

DevOps Amsterdam brings together developers and operations people in a common goal: destroy silos and remove obstacle to deploy and maintain awesome software and reliable infrastructures. 

 https://www.meetup.com/DevOpsAmsterdam/

7. Internet of Things

Amsterdam IoT Living Lab is the Meetup group that gives presence to the Amsterdam project of creating a series of iBeacon and IoT enabled Living Labs to stimulate innovative startups, entrepreneurs, and SMEs across public and private industry sectors.

http://www.meetup.com/Amsterdam-IoT-Living-Lab/

8. Node

NodeSchool Amsterdam offers do-it-yourself open source workshops created by the community, for the community. NodeSchool events are a great incentive to work through the workshops with fellow local developers, sharing advice if you're ever stuck or are curious about alternative solutions.

https://www.meetup.com/nodeschool-amsterdam/

9. Hackers and founders

The Meetup where hackers and startup founders meet. This is the Meetup group by the co-working space of the same name.

https://www.meetup.com/Hackers-and-Founders-Amsterdam-NL/

10. Appsterdam

Appsterdam provides common ground for all App Makers, regardless of platform, occupation, or business model, in Amsterdam and beyond.

http://www.meetup.com/Appsterdam/

*You might also be interested in: Rough guide on how to connect to Amsterdam’s startup community.