Offensive security services platform providing pentest-as-a-service with access to a vetted community of security researchers for app testing.
Top Rated10+ YearsEnterprise
Application Security TestingThe Top 10
The absolute best in application security testing
Elite threat intelligence and incident response firm, now part of Google Cloud Security.
Top Rated15+ YearsEnterprise
Cybersecurity ServicesApplication Security Testing
Comprehensive cybersecurity platform provider specializing in network security, cloud security, and AI-driven security operations.
Top Rated15+ YearsEnterprise
Cybersecurity ServicesApplication Security Testing
Cloud-based IT security and compliance platform with web application scanning (WAS) for automated DAST and API security testing.
Top Rated15+ YearsEnterprise
Application Security Testing
Crowdsourced security platform providing managed bug bounty programs, PTaaS, and vulnerability disclosure for application security testing.
Top Rated10+ YearsEnterprise
Application Security Testing
Leading bug bounty and PTaaS platform connecting organizations with vetted global security researchers for application vulnerability testing.
Top Rated10+ YearsLarge Team
Application Security Testing
Premier security testing platform combining AI-powered automation and elite ethical hackers for continuous penetration testing at scale.
Top Rated10+ YearsLarge Team
Application Security Testing
AI-powered API security platform providing runtime protection, API discovery, and behavioral analytics to stop API-based attacks.
Top Rated10+ YearsMid-Size
Application Security Testing
Unified API protection platform combining automated discovery, business logic vulnerability testing, and runtime security for applications.
Top Rated10+ YearsMid-Size
Application Security Testing
Software testing solutions provider with static analysis, API testing, and security-focused testing tools for enterprise application security.
Top Rated15+ YearsLarge Team
Application Security TestingTop 10 Application Security Testing Agencies — FAQ
Common questions about the best application security testing agencies in California.
Who is the #1 application security testing agency in California in 2026?
As of 2026, the top-ranked application security testing agency in California on AgencyCluster is Cobalt, with an AgencyCluster Score of 97/100. Rankings are based on verified evidence across credibility, proof of work, reputation, category specialization, delivery maturity, and freshness. Rankings are updated periodically as new evidence becomes available.
How were the top 10 application security testing agencies in California selected?
This list features 10 agencies selected from AgencyCluster's curated directory. Each agency was evaluated using the AgencyCluster Score (0–100), with particular weight on demonstrated expertise in application security testing. Only agencies with verified credentials are eligible, and rankings cannot be purchased. The agencies on this list average 19+ years of experience. For full methodology details, see our How We Rank page.
What should I look for when choosing a application security testing agency from this list?
Ask for case studies with measurable outcomes relevant to your specific project. Check team composition — do they have specialists or generalists? Ask about their communication cadence and project management approach. Request client references from companies of similar size and complexity to yours.
How much do the top application security testing agencies typically charge?
Project costs vary significantly based on complexity, team size, and engagement model. Request proposals from 3–5 agencies to benchmark pricing. Be cautious of quotes that are dramatically lower than others — they usually indicate corners being cut.
Trusted Rankings
Every agency on this list has been reviewed by our editorial team. Rankings are based on our transparent methodology which evaluates credibility, outcomes, and reputation.
No paid rankingsVerified credentialsUpdated regularly
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