Custom websites
Websites that bring in customers: fast, mobile-friendly, and built around how your business works.
- Sites that make a strong first impression
- Online stores that make buying easy
- Landing pages that bring in customers
Fueling small business automation.
Slow websites, messy spreadsheets, and tools that don't talk to each other cost you money every day. CO5 Tech replaces them with clean, custom tech that runs quietly in the background while you run your business.
Based in San José · Serving the whole Bay Area
One point of contact, start to finish. You work directly with the person building your project.
Websites that bring in customers: fast, mobile-friendly, and built around how your business works.
Stop losing hours to spreadsheets. Custom tools take care of the busywork so you can focus on growing.
Not sure what you need? I'll cut through the noise, find the right tools, and set them up so they actually work.
Wi-Fi down? Email broken? I'll get your office tech running and keep it running.
Everything is built for your business, not squeezed into a Wix or Squarespace theme.
I'll meet you in person and see how your business actually runs.
One point of contact. No account managers, no runaround.
I'm working with a large logistics company to streamline their supply chain and day-to-day workflow: replacing manual steps and scattered tools with one system their team can rely on.

I'm the founder of CO5 Tech. I build websites and business systems for Bay Area businesses that want technology that simply works, from small shops to a large logistics company I'm working with now.
I'm also a student at San José State University, so I'm always learning the newest tools and bringing them to my clients.
I'm based in San José, so I can meet you in person, see how your business actually runs, and build around that.
Tools I build with
CO comes from chemistry: something you never see, but that's always at work. That's how good tech should run in your business. The 5 is the S in my last name, Coss. Put them together and you get CO5.
CO5 = CO + the S in Coss
CO5 Tech is a San José, California tech studio founded by R. Diego Coss. It builds custom websites, business systems (order tracking, inventory, shipping labels, dashboards, workflow automation), and provides tech consulting and IT setup and support for small and mid-sized businesses in the Bay Area.
CO5 Tech is based in San José, California and works with businesses across San José, Silicon Valley, and the greater Bay Area. Meeting in person is available for local clients.
Everything is custom-built for your business instead of using a template, you meet in person with a local developer, and you work directly with the person building your project, with no account managers in between.
Every project is different, so pricing depends on what you need. The first conversation is free: tell me about your business and your budget, and I'll tell you what's possible.
It depends on the size of the project. After the first conversation you'll get a clear plan and timeline before any work starts.
You work directly with R. Diego Coss, the founder of CO5 Tech, from the first conversation to launch and support.
Fill out the contact form at co5tech.com with what you need. You'll get a reply within 1 to 2 business days to set up a free first conversation.
Tell me what you need and I'll get back to you within 1–2 business days. The first conversation is free.