Continuous API security testing and runtime protection platform specializing in mobile, web, and cloud application security analysis.
Top Rated10+ YearsMid-Size
Application Security TestingTop 10 Elite
The very best agencies • View detailed Top 10
Agencies 11–25
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Leading software QA outsourcing company offering AI-driven testing, automation, and manual QA services for startups to Fortune 500 companies.
Top Rated15+ YearsEnterprise
QA & Test AutomationApplication Security Testing
Mobile security company providing defense-grade automated mobile application security testing and third-party app vetting solutions.
Top Rated15+ YearsSmall Team
Application Security Testing
Full lifecycle API security platform using distributed tracing for deep visibility, testing, and runtime protection of application APIs.
Rising Star5+ YearsMid-Size
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Runtime application security platform embedding code analysis and attack prevention directly into the SDLC via patented instrumentation.
Rising Star10+ YearsMid-Size
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Lightweight, customizable SAST platform for CI/CD pipelines providing fast code scanning with developer-friendly rules and low false positives.
Rising Star5+ YearsEnterprise
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Next-gen application security observability platform providing runtime analysis, SCA, and SBOM generation for cloud-native applications.
5+ YearsSmall Team
Application Security TestingComplete Top 25 Application Security Testing Agencies in California
Full numbered list of all 17 agencies
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Complete Top 25 Application Security Testing Agencies in California
Full numbered list of all 17 agencies
- 1.Cobalt — California
- 2.Mandiant (Google Cloud) — California
- 3.Palo Alto Networks — California
- 4.Qualys — California
- 5.Bugcrowd — California
- 6.HackerOne — California
- 7.Synack — California
- 8.Salt Security — California
- 9.Cequence Security — California
- 10.Parasoft — California
- 11.Data Theorem — California
- 12.QASource — California
- 13.Quokka (formerly Kryptowire) — California
- 14.Traceable AI — California
- 15.Contrast Security — California
- 16.Semgrep (Return to Corp) — California
- 17.Deepfactor — California
Top 25 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 25 application security testing agencies in California selected?
This list features 17 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 16+ 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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