13Core

Carbondale, Illinois, United States

Website design, development, hosting, and marketing from WordPress core contributors

Women-owned and based in Carbondale, Illinois, 13Core has run as a web and marketing firm since it was founded on November 1, 2011. The staff includes WordPress core contributors and digital marketing specialists, each with at least 10 years of experience in their field, and the firm has reached 14 years in business, more than 100 clients served, and over 50 custom sites built.

Services cover website design, frontend and backend development, technical SEO, Google Ads management, and paid and organic social media campaigns, paired with managed web hosting and WordPress-specific hosting. Beyond initial builds, 13Core has cleaned more than 400 hacked websites and monitors client sites for uptime through evenings, weekends, and holidays.

Day-to-day operations follow set rules meant to protect client sites and response times. Office hours run 7:30am to 4:30pm Central, Monday through Friday, with a four-hour maximum turnaround for first responses to client emails, and no site changes go live on Fridays besides content updates. One project, built for a regional food guide, was recognized as the Southern Illinois Eats Best Website.

15
YEARS IN BUSINESS
2
SERVICES

Capabilities

Services

What these services involve

Social Media Management (SMM)
Ongoing social content planning, publishing, and community management.
Website Optimization
Improvements to speed, UX, SEO foundations, and site performance.

Agency details

Team size
11-50 people
Founded
2011 (15 years)

About this agency on Agency List

13Core holds an Agency List Score of 67 out of 100.

That score is higher than 16% of the 36,920 agencies Agency List has assessed so far.

The Agency List Score measures how well an agency documents its work in public: named clients, quantified outcomes, and whether those outcomes are attributed to the agency rather than to the client.

It does not measure client satisfaction, price, or availability.

How the Agency List Score is measured

Assessment date

Agency List assessed 13Core in September 2026, reading 6 pages published on 13core.com.

The score reflects what 13Core had published by that date; anything published since has not been read.

Directory hubs

Browse the wider directory 13Core is listed in.