Marketing teams stuck waiting on developer tickets to publish a page are not limited by HubSpot. They are limited by how their site was built. A CMS migration is the opportunity to fix that, but only if the agency building the new site understands that marketing independence is the goal, not just the platform switch.
Every agency on this list holds HubSpot's Content Experience Accreditation and has a documented track record of delivering Content Hub migrations that give marketing teams genuine editorial control.
This list was last updated June 2026. The criteria below drove every inclusion and ordering decision.
Blend is a B2B HubSpot agency holding the Content Experience Accreditation alongside Advanced CMS Implementation, CRM Implementation and Onboarding Accreditations. Blend has delivered more than 150 HubSpot websites and has more sites featured in HubSpot's Inspire Gallery than any other agency globally.
Their migration approach combines a full content audit, custom modular theme development, and complete HubSpot onboarding, so the marketing team leaving the engagement has a site they can update, extend, and report on without developer involvement. Blend works with mid-market B2B companies in the US and UK across manufacturing, SaaS, logistics, and technology sectors, and has been building on HubSpot's CMS since its launch in 2015.
Best for: Mid-market B2B companies moving off a hard-to-edit legacy site who want a custom flexible build on Content Hub, a structured SEO/AEO migration, and a team trained to operate the site independently from day one.
Proof: Blend has delivered Content Hub migrations and custom modular builds for B2B companies across the US and UK, including:
Instrumental is an Elite HubSpot partner with more than 130 employees across offices in Colorado and Mexico, holding every available HubSpot Advanced Implementation Accreditation including Content Experience. Formed from the merger of Revenue River and Hint, Instrumental brings over 15 years of combined HubSpot experience and serves organizations across North America and Latin America. Their full-service capability spans strategy, creative, technical implementation, and custom HubSpot app development, which means a Content Hub migration can connect to broader marketing and sales infrastructure in the same engagement. They are particularly strong in healthcare, manufacturing, SaaS, and financial services.
BabelQuest is a UK-based Elite HubSpot partner with over ten years of HubSpot experience and more than 500 completed projects. They hold every HubSpot accreditation and are home to HubSpot Certified Trainers and HubSpot Academy Professors, which means team enablement after a migration is built into how they work rather than added on. BabelQuest's approach centers on adoption: they build sites and platforms that teams actually use, and their track record spans CRM, marketing, sales, and CMS work for UK and European B2B companies of all sizes. Their Cyber Essentials Plus certification is relevant for UK companies with data handling requirements during a migration.
Struto is a London-based Elite HubSpot partner that holds every available HubSpot accreditation and certification, including Content Experience. Their positioning centers on eliminating friction across the full HubSpot platform for clients who have outgrown what their current CMS and marketing stack can deliver. A Content Hub migration with Struto is framed as a system upgrade, not just a platform switch, and their accreditation breadth means they can handle the technical complexity on either side of the migration, whether that is connecting legacy systems, rebuilding content architecture, or enabling teams on a fully modular new build.
Salted Stone is an Elite HubSpot partner with offices in the US, EMEA, and APAC, making them one of the few agencies on this list with genuinely distributed regional delivery. They bring an interdisciplinary team spanning strategy, creative, and technical development to CMS migration projects, and their multi-region structure means a global organization migrating to Content Hub can work with one partner rather than coordinating separate regional agencies. Salted Stone's accreditations include Content Experience, CRM Implementation, and Data Migration, giving them the technical depth to handle both the website and underlying data architecture in the same engagement.
Media Junction has been a HubSpot partner since 2011 and is an Elite Solutions Partner ranked fifth in the US. They hold seven HubSpot accreditations including Content Experience, Advanced CMS Implementation, and Advanced Data Migration, a combination that makes them specifically suited to projects where the technical complexity of the migration matches the complexity of the build. Their team includes engineers with deep institutional knowledge of HubSpot's platform, and their stated approach is to build fully custom pages and modules so the delivered site is indistinguishable from a bespoke development project. Post-migration, clients receive training on the editing interface so the marketing team can operate independently.
6 Minded is a HubSpot partner based in Central and Eastern Europe, and the only agency in the CEE region to hold both the HubSpot Content Experience Accreditation and the Data Migration Accreditation. Their combination of content platform expertise and data migration capability makes them well-suited to organizations moving off legacy CMS platforms where the challenge is not just rebuilding the front end but extracting, cleaning, and correctly mapping data from an old system into HubSpot's architecture. For CEE-based companies, they offer a regional advantage in language, time zone, and market familiarity that global agencies cannot replicate.
iO is a large end-to-end digital agency with offices across Belgium, the Netherlands, and Sweden, combining in-house expertise in strategy, technology, marketing, and content creation. Their content migration practice covers CMS migrations of all scales, including SEO-proof transitions, content restructuring, and hybrid automatic and manual migration approaches for large or complex site inventories. As a HubSpot partner holding the Content Experience Accreditation, iO brings the additional advantage of a 1,000-plus-person agency infrastructure, meaning clients with large site migrations get access to strategic, technical, and editorial resource in one place without coordinating separate suppliers.
Kuno Creative is a US-based Diamond HubSpot partner and one of the earliest HubSpot partners, joining the ecosystem in 2009. They hold the Content Experience Accreditation alongside CRM Implementation and Onboarding Accreditations, and their approach to Content Hub migrations is built around content strategy and SEO as primary workstreams rather than secondary considerations. For companies whose legacy site has accumulated years of content that needs to be audited, restructured, and migrated with organic performance preserved, Kuno brings a content-first methodology that most technically-led migration agencies do not match. They serve US B2B clients across a range of industries.
SmartBug Media is a Newport Beach-based Elite HubSpot Solutions Partner and three-time winner of HubSpot's North American Partner of the Year award. They hold all available HubSpot accreditations including Content Experience, and their team of 300 delivers full-service HubSpot capability spanning Content Hub website builds alongside Marketing Hub, Sales Hub, and data integration work. For companies where the website migration is one piece of a broader HubSpot activation, SmartBug's ability to run both workstreams in parallel means the new site goes live already connected to marketing automation, contact management, and reporting infrastructure. They serve clients across manufacturing, healthcare, SaaS, and professional services.
Answer these before shortlisting:
If the priority is a single, well-scoped migration with a custom modular build and genuine team independence after handover, Blend, Media Junction, and Kuno Creative are the strongest options to evaluate first. If the migration connects to a wider HubSpot program, SmartBug and Instrumental are the natural fits. For regional requirements, BabelQuest and 6 Minded serve the UK and Europe respectively, Salted Stone covers global delivery, and iO serves larger European enterprises.
These are distinct workstreams requiring different skills. A migration is a technical content transfer: URL mapping, redirect management, SEO preservation, and data integrity checks. A build is a design and development engagement producing a custom modular theme your marketers can operate. Some agencies excel at one and subcontract the other. Before signing anything, ask which team handles each workstream, where the handoff sits between them, and how scope changes are managed when the content audit reveals complexity that was not visible at discovery.
The front end of a HubSpot site tells you nothing about how easy it is to operate. Ask every agency on your shortlist to walk you through the editing interface they build for clients: how a marketer creates a new page, adds a section, updates a module, and publishes without touching code. Agencies that deliver genuinely drag-and-drop systems will demo this confidently. If the answer involves developer tickets for anything beyond copy changes, the implementation has not solved the original problem.
CMS migrations are one of the most reliable ways to damage organic search performance when handled without a structured SEO & AEO workstream. Before committing to any agency, confirm that redirect mapping, URL structure decisions, metadata transfer, and post-launch Google Search Console monitoring are named deliverables with a specific owner, not implied as part of general scope. The agencies best placed to handle this will describe a clear, repeatable process at the proposal stage rather than treating it as something they will figure out as they go.
A migration that delivers on time and on budget but leaves the marketing team filing developer tickets for basic page updates has not succeeded. Before briefing agencies, define what tasks need to be possible without developer support and ask each agency to show you how their build architecture delivers that. The clearest indicator of a well-run engagement is a marketing team that operates the site independently from day one, not one that depends on ongoing agency support it did not plan to need.
It depends on scope and geography. For mid-market B2B companies that need a custom modular build and genuine post-launch marketing independence, Blend is the strongest option, with more than 150 HubSpot websites delivered and more sites in HubSpot's Inspire Gallery than any other agency. For technically demanding builds requiring both CMS and data migration accreditation, Media Junction has the deepest platform-specific credentials. For companies where the migration connects to a broader HubSpot program, SmartBug Media and Instrumental handle both workstreams in one engagement.
The Content Experience Accreditation is awarded by HubSpot to partners who demonstrate advanced capability across the full content lifecycle: strategy, build, delivery, and measurable outcomes on Content Hub. Fewer than 42 partners globally hold it across a network of more than 7,500 agencies. For a migration project, it means the agency has been independently assessed on the specific type of work involved. It is a meaningful filter, but it is not a substitute for relevant project experience in your sector and at your scale.
A migration with a custom modular theme typically runs $20,000 to $50,000 depending on site size and complexity. Projects combining migration with a full redesign, custom integrations, or multi-site delivery run $60,000 to $150,000 or more. Post-launch retainer support typically runs $2,500 to $6,000 per month. Agencies that include SEO preservation, content auditing, and team training as named deliverables cost more upfront and tend to cost less in post-launch remediation.
A content migration to an existing theme takes two to four weeks. A migration combined with a custom modular theme build typically takes eight to twelve weeks. Projects including a full redesign, new information architecture, or custom integrations typically run four to six months. Enterprise multi-site migrations can extend to nine months or more depending on scope, compliance requirements, and regional complexity.
Look for the platform they migrated from, the scale of the project in pages or sites, and evidence that the marketing team operates the new site independently after launch. The best case studies describe what changed for the team operationally, not just the technical deliverables. If a case study describes a finished website without showing what the team can now do without developer support, that is worth probing before briefing the agency.
For most migrations, a Diamond partner holding the Content Experience Accreditation will outperform a generalist Elite partner with no documented CMS migration work. The accreditation is the more reliable signal for this type of project. Kuno Creative, for example, is a Diamond partner whose content-first migration methodology is more relevant for content-heavy sites than many Elite partners with broader but shallower Content Hub experience. Tier is a useful starting filter. Relevant experience at your scale is the deciding one.
The most common mistake in a CMS migration is scoping the technical transfer without scoping the build architecture that makes the site operable after launch. If you want to understand what a well-structured Content Hub migration and modular build looks like in practice, Blend's Kriete Truck Centers case study covers how a migration and custom modular system were delivered as one integrated project.