--- title: "Technical SEO Services for JavaScript-Heavy Sites | Arbocode" description: "Crawl budget, rendering and Core Web Vitals fixes from technical seo services by engineers who change the codebase directly instead of just flagging issues." url: https://arbocode.com/services/technical-seo --- 1. [Home](https://arbocode.com/) 2. [Services](https://arbocode.com/services) 3. Technical SEO Search # Technical SEO Services for Crawl, Rendering and Migration Issues Crawl budget, rendering and Core Web Vitals problems diagnosed and fixed by engineers who can also work in the codebase beneath them. [Get a free estimate](https://arbocode.com/get-a-quote?service=technical-seo) [Speak with an engineer](https://arbocode.com/contact) NDA on request · Free, no-obligation estimate · Reply within one business day NDA signed before we start Full IP ownership on payment Your repository from the first commit Live demo at the end of every sprint Built by senior engineers [How we work](https://arbocode.com/process) Technical seo services here are the engineering side of search: crawl budget and indexation problems, JavaScript rendering issues on client-rendered sites, Core Web Vitals remediation, structured data implementation, site migrations, log-file analysis, and international hreflang setup for sites serving several regions. Strategy and content work sit with our general SEO service, and Google Business Profile and citation work sit with local SEO. Most technical SEO vendors can identify a problem in a crawl report and recommend a fix that a client's own developers then have to interpret and implement, often incorrectly, weeks later. Because we build software, the same engineer who diagnoses a rendering issue on a React or Next.js site can also open the codebase and fix the server-side rendering configuration causing it. That closes the loop between diagnosis and implementation that a pure consulting engagement cannot. We work from server log files, not just simulated crawl tools, when diagnosing crawl budget problems, since log data shows what search engine bots actually requested and rendered rather than what a third-party crawler simulated. That distinction matters most on large sites where crawl budget is genuinely constrained. ## Problems we are usually brought in to solve - Our site is built in React or another JavaScript framework and pages are not getting indexed correctly - Core Web Vitals scores are poor and we do not know which part of the stack is causing it - We are migrating to a new platform or domain and are worried about losing existing rankings - Our site has thousands of pages and search engines seem to be crawling the wrong ones - We operate sites in multiple languages or countries and search engines show the wrong version to the wrong users - Structured data errors are showing up in Search Console and nobody on our team can read the schema What we deliver ## Technical SEO services - ### JavaScript rendering audits Diagnosing whether content built with React, Vue or Angular actually reaches the indexed page, comparing rendered DOM against what a crawler retrieves, and fixing the server-side or static rendering configuration when it does not. - ### Core Web Vitals remediation Diagnosing LCP, INP and CLS issues down to the specific asset, script or layout pattern causing them, and implementing the fix directly in the codebase. - ### Crawl budget and log-file analysis Analyzing server logs to see what search engine bots actually crawl, identifying wasted crawl budget on low-value or duplicate URLs, and correcting it through robots directives and internal linking. - ### Structured data implementation Schema markup for products, articles, FAQs and organizations, validated against Google's structured data requirements rather than copied from a generic template. - ### Site migration planning Full redirect mapping, URL structure planning and staged rollout for a domain, platform or URL structure change, built to preserve existing ranking signals. - ### International hreflang setup Correct hreflang implementation across language and country variants, including the common bidirectional errors that cause search engines to serve the wrong regional version. - ### Indexation and duplicate content audits Identifying pages competing against each other for the same query, thin or near-duplicate templates, and consolidating them through canonicalization or redirects. You receive ## Deliverables - Technical audit with prioritized findings by impact - Redirect map for migrations - Core Web Vitals report tied to specific fixes shipped - Validated structured data implementation - Log-file crawl analysis - Hreflang implementation across language or country variants - Post-migration monitoring report How we work ## Our technical seo process 1. ### Technical audit A full crawl of the site combined with log-file data and Core Web Vitals field data, to separate real problems from noise a generic scanning tool would flag. 2. ### Prioritization Findings ranked by actual traffic and indexation impact, since a large site typically surfaces dozens of issues and only a handful matter enough to fix first. 3. ### Implementation Fixes implemented directly in the codebase, whether that is rendering configuration, redirect rules, schema markup or asset loading changes, rather than handed off as a recommendation document. 4. ### Validation Confirming the fix worked by comparing rendered output, Search Console data and, where relevant, updated log data, rather than assuming a code change resolved the issue. 5. ### Monitoring Ongoing tracking of crawl stats, indexation and Core Web Vitals after implementation, particularly important in the weeks following a migration. ## Log files over simulated crawls Most technical SEO audits rely entirely on a third-party crawler simulating how a search engine sees the site. That is useful, but it is a simulation, and on large sites it can miss what search engine bots are actually doing. We pull and analyze server log files directly, which show the real requests from Googlebot and other crawlers: which URLs get hit, how often, and which get ignored. That data catches crawl budget waste, bots repeatedly hitting faceted navigation or session-ID URLs, that a simulated crawl alone would not reveal, and it is the more reliable signal on any site large enough for crawl budget to matter. ## Fixing rendering issues in the codebase, not around it A JavaScript rendering problem, where content is present in the browser but missing from what a search engine indexes, usually traces back to a specific rendering decision: client-side-only rendering for content that should be server-rendered, a hydration mismatch, or content gated behind a client-side data fetch that never resolves in time for indexing. Because our technical SEO team includes engineers who work in the same frameworks, React and Next.js most often, we diagnose the exact line of rendering logic causing the gap and fix it directly, rather than recommending a rendering strategy change that a client's own developers then have to interpret weeks later. Technology ## Technologies we use - [Next.js](https://arbocode.com/technologies/nextjs) - [React](https://arbocode.com/technologies/react) - [WordPress](https://arbocode.com/technologies/wordpress) - [Webflow](https://arbocode.com/technologies/webflow) - [AWS](https://arbocode.com/technologies/aws) Industries ## Technical SEO by industry - [Retail & E-commerceInventory, POS and storefront software that stays synchronized across every channel, with EDI connected for your wholesale partners.](https://arbocode.com/industries/retail-ecommerce) - [Professional ServicesEngagement management, time tracking and client portals designed around how consulting and advisory firms bill for their time.](https://arbocode.com/industries/professional-services) - [Media & EntertainmentStreaming, subscription and rights management software organized around DRM licensing and content availability by territory.](https://arbocode.com/industries/media-entertainment) - [Travel & HospitalityBooking engines, channel managers and guest apps that keep rate and inventory data consistent across your PMS, OTAs and GDS connections.](https://arbocode.com/industries/travel-hospitality) Solutions ## Systems we build with this service - [Cloud MigrationPlanned waves of moving existing workloads to the cloud, with a migration strategy picked for each workload and no single approach forced on everything.](https://arbocode.com/solutions/cloud-migration) - [System IntegrationConnecting the CRM, ERP, billing and internal systems you already run, so data moves between them with nobody copying it by hand.](https://arbocode.com/solutions/system-integration) Budget ## What drives cost and timeline - ### Site size and architecture complexity A site with a few hundred pages on a standard CMS is a different technical scope than one with hundreds of thousands of pages generated dynamically. - ### Migration scope A full domain and platform migration with a complete redirect map and URL restructure costs more than a smaller-scale URL pattern change. - ### Rendering architecture A client-rendered single-page application typically needs more remediation work than a server-rendered or statically generated site. - ### Number of language or country variants International hreflang complexity scales with the number of region and language combinations a site needs to serve correctly. [Get a free estimate](https://arbocode.com/get-a-quote?service=technical-seo&src=pricing%5Fblock) [See engagement models](https://arbocode.com/pricing) Compliance ## Standards we design and build to None of these is a certification or attestation held by this agency. They are the standards we design and build client systems to, so your own audit or assessment starts from a sound base. - ### GDPR / UK GDPR Personal data handled on a lawful basis, with data minimisation and a documented retention policy. - ### HIPAA safeguards Administrative, physical and technical safeguards applied where a system touches protected health information. - ### PCI DSS scope reduction Card payment flows tokenised through a certified processor so cardholder data never touches your systems. - ### SOC 2 readiness Access control, change management and audit logging built in from day one, ready for a client's own SOC 2 audit. - ### WCAG 2.2 AA Keyboard navigation, colour contrast and screen-reader labelling checked against the AA success criteria. - ### OWASP ASVS Authentication, session handling and input validation reviewed against the Application Security Verification Standard. We list certifications only when they are real and current. [See our security practices →](https://arbocode.com/security) FAQ ## Questions about Technical SEO Why is our React or Next.js site not getting indexed properly? The most common cause is content that renders correctly in a browser but is missing from what a search engine actually retrieves, usually because content loads client-side after the initial page load rather than being present in server-rendered or statically generated HTML. We diagnose this by comparing rendered DOM output against what a crawler receives, then fix the rendering configuration directly. Will a site migration cause us to lose our current rankings? A migration carries real risk if redirects and URL mapping are handled poorly, but with a complete redirect map, preserved internal linking structure and a monitored rollout, most sites recover ranking signal within weeks rather than losing it permanently. We treat redirect mapping as the highest-priority deliverable in any migration project. What causes poor Core Web Vitals scores and can you actually fix it? Common causes include unoptimized images, render-blocking scripts, layout shifts from late-loading content, and slow server response times. Because our team can implement fixes directly in the codebase, whether that means image optimization, script deferral or layout changes, we address root causes rather than only reporting the scores. How do you diagnose crawl budget problems on a large site? Primarily through server log-file analysis, which shows exactly which URLs search engine bots requested and how often, rather than relying only on a simulated crawl. That reveals wasted crawl activity on low-value URLs like faceted navigation or session parameters, which we then address through robots directives, canonicalization and internal linking changes. Can you fix hreflang errors across our international sites? Yes. Hreflang errors are common, particularly bidirectional mismatches where one language version references another correctly but the reverse reference is missing or wrong. We audit every language and country variant, correct the implementation, and validate it against Search Console's international targeting reports. Do you write the structured data or just tell us what schema to use? We implement it directly, since schema markup with even small syntax or property errors often fails validation entirely. We build and validate structured data for the page types that matter to your business, products, articles, FAQs, organization data, against Google's current structured data guidelines. Related ## Related services - [SEO ServicesKeyword architecture, content briefs, on-page work and reporting from a team that can also fix what is broken in the site underneath.](https://arbocode.com/services/seo) - [Local SEOGoogle Business Profile management, citation cleanup and location pages written for each address instead of one template copied across a store list.](https://arbocode.com/services/local-seo) - [Web DevelopmentWe build company websites, content platforms and headless front ends that load fast, rank in search and send your sales team a steady flow of form submissions.](https://arbocode.com/services/web-development) - [Cloud & DevOpsWe design cloud infrastructure as code, build CI/CD pipelines and prepare your team for incidents before they happen.](https://arbocode.com/services/cloud-devops) ## Price your technical seo project Send a short description of the project. A senior engineer reads each request and answers with questions, next steps and an early budget range. [Get a free estimate](https://arbocode.com/get-a-quote?service=technical-seo) [Speak with an engineer](https://arbocode.com/contact)