Shopify
Shopify is the best platform for online stores, as well as a diverse company of happy polyglots who hack on everything between UX, data warehouses, and low-level CRuby VM performance issues. 
We value personal growth, and developer quality of life in a huge way and show it by having safe deployment systems anyone can trigger; facilitated retrospectives + off-sites with Corey Haines; GitHub and PRs for everything; small, mixed teams of folks with 0 to 30 years of experience, and encouragement from the still-hacking CEO to give back to open source on company time.
<a href="http://shopify.com/careers" > – apply to any dev/ops job and mention HN and I’ll give you a hand.
Here’s a sampler of the current teams at work:
Reports
High throughput + realtime tools for customers; we hired the author of SkyDB to continue making it more awesome. People on this team have backgrounds in low-level kernel work,  Smalltalk VM development, and deployment of national wireless systems.
Stack
The right thing to do should be the easiest thing to do; this team works on things like implementing Kafka across the entire Shopify system to let anyone pub/sub to any call-site, opening the door for easy instrumentation/experimentation.
Performance
We’re in the process of sharding Shopify in order to isolate and better service stores experiencing $3000000+/hour flash sales. People working on IBM’s specialized JVM are now hacking here, while also contributing context threading patches to CRuby off the side of their desk for fun.
Point of Sale
If you like making beautiful hardware + beautiful software that you can see used by customers who tell you this is the Holy Grail of retail systems, then you go here.
Operations
Engineers here work on projects like Chef, distributed cloud+iron failover systems, DDOS mitigation stuff and our new datacenters.
More teams
Data (giant, columnar data-stores + PhD withbackgrounds in finance and astrophysics)
Admin (Batman.js + UX professionals + designers who code)
Self help (machine learning for people learning)
Apps (JS SDKs for seamless iframes + APIs)
Checkout (provide low-latency experiences while dealing with high-latency payment gateways; don’t drop any of the zillion$$$ going by)
Platform + Growth (biz dev science + gamification of ecommerce education)
Internal tools (Fast Company-covered staff bonus system aka “Unicorn”, Bayesian classification of customer questions assigned to support experts, hand-made phone queueing systems wrapped around Twilio, etc., etc.)
Billing (hard-core testers need only apply)
Payments (integrations with Stripe + fraudster f-ing)
Core/API (everything not here)
(more but secret)
Seeking full-time programmers, and data analysts to work in Toronto, Montreal, and Ottawa, Canada. We’ll help with visas.
Seeking operations staff anywhere (remote friendly).
<a href="http://shopify.com/careers" > – apply to any dev/ops job and mention HN and I’ll give you a hand.