Top API & Integration Development Companies in California

We ranked 6 API and integration developers in California on client reviews, how many are verified, service focus and profile completeness. Updated October 2026. How rankings work

Specialists who connect the tools a business already uses, build APIs and automate the data flowing between systems.

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Codepilot
San Francisco agency that builds and maintains custom web apps, mobile apps and APIs for companies from startups to large enterprises.
No reviews yet
San Francisco, CA
- Web Development
- API & Integration Development
- Mobile App Development
Team
10-49 people
WebCentriq
San Diego software studio delivering fixed-price web apps, mobile apps, MVPs and business automation in 4 to 16 weeks.
No reviews yet
San Diego, CA
- Custom Software Development
- Web Development
- Mobile App Development
Projects from
$15,000+
Team
50-99 people
Primero Systems
San Diego firm that builds, modernizes and supports custom enterprise applications, active since 1994.
No reviews yet
San Diego, CA
- Custom Software Development
- API & Integration Development
- AI & Automation
Team
50-99 people
Nisman Solutions
San Diego team of software engineers and architects building custom web, mobile, e-commerce and integration projects.
No reviews yet
San Diego, CA
- Custom Software Development
- Web Development
- API & Integration Development
Team
10-49 people
AKOS
Scottsdale AI and data studio and certified Palantir partner building operational systems for manufacturing, logistics and biotech.
No reviews yet
San Diego, CA
- AI & Automation
- Custom Software Development
- API & Integration Development
Clear Digital
San Jose agency that designs and builds enterprise websites and CMS platforms for B2B technology and other complex companies.
No reviews yet
San Jose, CA
- Web Development
- UX/UI Design
- API & Integration Development