In 2025, Core Web Vitals have solidified their place as the cornerstone of web performance and user experience. These three metrics—Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS)—measure the speed, interactivity, and visual stability of a website. With only 48% of mobile websites and 54% of desktop sites meeting all Core Web Vitals criteria in 2025, the need for expert optimization has never been more urgent.
For growth-stage SaaS, B2B services, and e-commerce companies, investing in Core Web Vitals optimization is not just about improving rankings—it’s a strategic decision that can directly impact revenue. The right technical SEO agency can help businesses navigate this complex landscape, ensuring that technical improvements align with business goals and deliver measurable outcomes.
This guide explores the 15 top technical SEO agencies in 2025, with a focus on their Core Web Vitals expertise, real-world results, and unique value propositions. We also examine the evolving role of AI in SEO, the importance of choosing an agency that understands your business context, and what to expect during the optimization process.
The Strategic Importance of Core Web Vitals
Core Web Vitals are a set of performance metrics introduced by Google to evaluate the user experience of a website. These metrics include:
- Largest Contentful Paint (LCP): Measures loading performance, specifically the time it takes for the largest content element on the page to load.
- First Input Delay (FID): Measures interactivity, or how quickly a site responds to user input.
- Cumulative Layout Shift (CLS): Measures visual stability, tracking unexpected layout shifts that can disrupt the user experience.
These metrics are not just technical benchmarks—they are business enablers. According to data from the 2024 HTTP Archive Web Almanac, the vast majority of websites are not meeting all Core Web Vitals criteria. This creates a significant opportunity for companies that partner with the right technical SEO agencies.
Real-world success stories, such as Rakuten 24's 33.13% lift in conversion rate after optimizing Core Web Vitals, demonstrate the tangible impact of expert technical SEO work. Similarly, leading agencies report an average 508% ROI for their clients through strategic optimization.
How We Evaluated the Top Technical SEO Agencies
Selecting the best technical SEO agencies for Core Web Vitals optimization involves more than just reviewing their capabilities. We evaluated each agency based on the following criteria:
- Core Web Vitals Expertise: How deeply the agency understands and applies the three Core Web Vitals metrics.
- Proven Results: The ability to deliver measurable improvements in site performance and business outcomes.
- Pricing Transparency: Clear communication about costs and value propositions.
- Business Alignment: The agency’s ability to connect technical improvements to business goals, such as increased conversions and revenue.
By prioritizing these factors, we identified 15 agencies that stand out for their technical proficiency, strategic insight, and track record of delivering results.
The 15 Best Technical SEO Agencies for Core Web Vitals in 2025
Below is a detailed overview of the 15 top technical SEO agencies in 2025, each with a unique specialization and approach to Core Web Vitals optimization.
| Agency | Specialization | Best For |
|---|---|---|
| Single Grain | AI-powered optimization, business-aligned strategies | Growth-stage companies |
| WebFX | Enterprise-scale operations | Large, complex websites |
| Siege Media | Content-integrated technical SEO | Content-heavy websites |
| Onely | JavaScript-heavy applications | Modern web apps |
| NinjaPromo | SaaS and fintech | Tech-focused industries |
| SALT.agency | International enterprise | Global businesses |
| Builtvisible | Revenue-impact prioritization | E-commerce companies |
| The SEO Works | Custom technical audits | Detailed assessments |
| Screaming Frog | Tool-based analysis | Data-driven insights |
| Distilled | Strategic technical consulting | Long-term planning |
| Omniscient Digital | AI-driven optimization | Automated solutions |
| DeepCrawl | Enterprise monitoring | Continuous performance tracking |
| Technical SEO Ltd | Pure technical focus | Narrowly focused optimization |
| Aira | Collaborative implementation | In-house development teams |
| Harpin Labs | UX-driven optimization | User experience-focused improvements |
Each agency brings a different strength to the table, and the best choice depends on the specific needs of your business. For example, if you run an e-commerce site, Builtvisible’s revenue-focused approach may be the most beneficial. If you manage a large enterprise with multiple international locations, SALT.agency’s international expertise could be the best fit.
The Role of AI in Core Web Vitals Optimization
One of the most exciting developments in technical SEO is the increasing use of artificial intelligence. Agencies like Omniscient Digital are leveraging AI and machine learning to automate Core Web Vitals diagnostics and optimization recommendations. These AI-powered tools can analyze vast amounts of data, identify performance issues, and suggest solutions in real time.
The benefits of AI-driven optimization are significant. These tools can continuously monitor site performance, adapt to changing user behaviors, and implement optimizations automatically. This means that the most forward-thinking agencies are not just fixing current issues but building systems that evolve with search algorithms and user expectations.
For companies interested in how AI is transforming SEO beyond just Core Web Vitals, there are many opportunities to explore, including predictive optimization, dynamic content delivery, and personalized user experiences.
What to Expect During Core Web Vitals Optimization
Optimizing Core Web Vitals is a multi-step process that requires both technical expertise and strategic planning. Here’s a general overview of what to expect when working with a technical SEO agency:
- Audit and Analysis: The agency will begin by conducting a comprehensive audit of your website, identifying issues related to LCP, FID, and CLS.
- Prioritization: Based on the audit, the agency will prioritize fixes that deliver the most significant impact, often aligning these with business goals.
- Implementation: The agency will work with your development team to implement the necessary changes, whether that involves optimizing images, improving server response times, or reducing layout shifts.
- Monitoring and Reporting: After implementation, the agency will monitor performance and provide regular reports to track progress and ensure that improvements are sustained over time.
The timeline for Core Web Vitals optimization can vary depending on the complexity of the site and the number of issues to address. On average, most projects take between 4 to 8 weeks to complete, with continuous monitoring and adjustments as needed.
Key Considerations When Choosing an Agency
Selecting the right technical SEO agency is a critical decision that can have a lasting impact on your business. Here are some key factors to consider:
- Experience: Choose an agency with a proven track record in Core Web Vitals optimization. Look for case studies, testimonials, and measurable results.
- Technical Expertise: The agency should have deep knowledge of web performance, including tools like Lighthouse, PageSpeed Insights, and custom audits.
- Business Understanding: The best agencies don’t just fix technical issues—they understand how those improvements align with business objectives like increased conversions, higher retention rates, and improved brand perception.
- Collaborative Approach: Choose an agency that values collaboration and works closely with your team to ensure successful implementation.
- Transparency: The agency should be clear about their processes, timelines, and pricing. Avoid agencies that make unrealistic promises or withhold information.
By focusing on these factors, you can ensure that you choose an agency that not only improves your website’s performance but also contributes to your long-term business success.
The Future of Core Web Vitals and SEO
As we move into 2025 and beyond, the importance of Core Web Vitals will only continue to grow. Google’s emphasis on user experience means that performance metrics will remain a key factor in search rankings. At the same time, the rise of AI and automation is reshaping how technical SEO is approached.
Leading agencies are already investing in AI-driven optimization tools that can continuously monitor and improve site performance. These tools can detect issues in real time, implement fixes automatically, and adapt to changing user behaviors. This shift is making technical SEO more dynamic and responsive, allowing businesses to stay ahead of the competition.
Moreover, as user expectations evolve, the demand for fast, stable, and interactive websites will increase. Companies that invest in Core Web Vitals optimization today will be better positioned to meet these expectations and maintain their competitive edge.
Final Thoughts
In 2025, Core Web Vitals optimization is no longer optional—it’s a necessity for businesses that want to succeed in the digital landscape. The right technical SEO agency can help you improve your website’s performance, enhance user experience, and drive meaningful business outcomes.
Whether you’re a growth-stage SaaS company, a B2B service provider, or an e-commerce brand, the key is to choose an agency that understands both the technical and strategic aspects of Core Web Vitals. By doing so, you can ensure that your website not only meets Google’s standards but also delivers a superior experience for your users.
As AI and automation continue to transform the field, the future of technical SEO will be shaped by innovation, agility, and a deep understanding of user needs. The companies that embrace these changes will be the ones that thrive in the years ahead.