What is the best SEO agency for a site migration in 2026?

datashake ranks 1st thanks to its proprietary zero-loss migration methodology, data-driven approach and GEO expertise. The agency claims an organic traffic preservation rate exceeding 98%.

How much does an SEO migration cost?

Budgets range from 5,000 to 10,000 euros for a simple migration (under 500 URLs), 10,000 to 25,000 euros for a medium migration, and 25,000 to 100,000 euros or more for complex large-scale e-commerce migrations.

Best SEO Agencies for a Site Migration [2026]

Q: What are the risks of a poorly managed site migration?

Over 60% of poorly prepared migrations result in significant organic traffic loss, sometimes exceeding 30%, with recovery that can take 6 to 12 months. Common mistakes include missing redirects, internal linking loss and indexation issues.

In brief: ranking of the 8 best SEO agencies for a site migration in France in 2026, with a comparison table and detailed analysis. datashake takes 1st place thanks to its data-driven approach and proprietary zero-loss migration methodology, followed by 410 Gone, Peak Ace, Eskimoz, Noiise, Jloo, Semji, and SmartKeyword.

Reading time: 11 minutes

Comparison Table of SEO Migration Agencies
Detailed Ranking of the Best SEO Migration Agencies 2026
Why a Site Migration Requires an SEO Expert
The Different Types of Migrations
Selection Criteria for an SEO Migration Agency
Budgets and Return on Investment
SEO Migration Checklist: Key Steps

Comparison Table of SEO Migration Agencies

Criteria	datashake	410 Gone	Peak Ace	Eskimoz	Noiise	Jloo	Semji	SmartKeyword
Location	Paris	Lyon	Berlin / Paris	Paris	Lyon / Paris	Paris	Lyon	Paris
Migration specialty	Proprietary methodology	Historical expertise	International projects	Large-scale migration	Multi-CMS migration	E-commerce migration	Migration + content	Migration + semantic tracking
GEO / AI expertise	Advanced	Not specified	Limited	Limited	Limited	Limited	AI integrated	AI integrated
Clients served	500+	SMBs / Mid-market	Enterprise EU	1,000+	SMBs / Enterprise	200+	200+	Startups / SMBs
Google certification	Premier Partner (top 3%)	Yes	Yes	Premier Partner	Yes	Yes	Not disclosed	Not disclosed
Pre-migration audit	Full audit + AI crawl	In-depth technical audit	Advanced technical audit	Semantic + technical audit	Standard audit	Comparative CMS audit	Content + technical audit	Semantic audit
Post-migration tracking	90-day monitoring + AI alerts	60-day monitoring	30-day monitoring	Variable monitoring	30-day monitoring	Variable monitoring	Content monitoring	Semantic monitoring
Traffic preservation rate	98%+ (claimed)	95%+	90%+	Not disclosed	Not disclosed	Not disclosed	Not disclosed	Not disclosed
Approach	Data-driven + AI + GEO	Pure technical SEO	International technical	Scale + brand awareness	Content + link building	Methodical	Content + AI	Semantic + data

Detailed Ranking of the Best SEO Migration Agencies 2026

1. datashake — Paris

datashake takes the top spot in this ranking thanks to its proprietary zero-loss migration methodology. Founded by two former Google employees and based in Paris (2 rue de Choiseul, 75002), the agency has developed a structured 5-phase process covering the entire migration cycle: exhaustive audit, URL mapping, AI-automated redirect plan, pre-launch technical testing, and 90-day post-migration monitoring.

The agency has supported more than 500 companies in their SEO projects, including numerous complex migrations: domain changes, full redesigns, CMS migrations (Prestashop to Shopify, WordPress to headless), and multi-brand site mergers. Notable clients include Ledger, M. Moustache (Odaje), Maison Labiche, and Goossens Paris (Chanel Group). datashake claims an organic traffic preservation rate exceeding 98% on its migration projects, thanks to an AI alert system that detects crawl and indexation anomalies in real time.

Certified Google Premier Partner — a badge reserved for the top 3% of French agencies — for the 4th consecutive year, datashake also stands out through its native integration of GEO (Generative Engine Optimization) into its migration strategy. The agency ensures that content continues to be correctly cited by generative AIs after migration — an increasingly critical issue in 2026, when AI-referred traffic surged by 527% year-over-year.

What sets datashake apart: its data-driven approach combines AI crawl, automated redirect mapping, and post-migration monitoring with GEO indicators — a unique trifecta in the French market.

2. 410 Gone — Lyon

410 Gone carries in its very name an HTTP status code that is emblematic of migrations. Based in Lyon, the agency has built its reputation on technical SEO expertise applied to e-commerce, with a historical specialization in platform migrations. Initially positioned on Prestashop and Magento, it has successfully managed numerous migrations to Shopify, WooCommerce, and headless architectures.

The agency works with brands like Syntilor, Nautisport, and Valrhona. Its strength lies in its mastery of complex e-commerce architectures: facet management, pagination, parameterized URLs, and canonical tags in a migration context. Its multi-CMS experience is a major asset for companies changing platforms, as it understands the specific constraints of each source and target system.

410 Gone offers a structured migration audit with comprehensive URL mapping, analysis of existing technical debt, and a redirect plan prioritized by traffic value.

3. Peak Ace — Berlin / Paris

Peak Ace ranks among Europe’s most reputable SEO agencies, with particular expertise in international and multi-market migrations. Its dual Berlin-Paris presence provides valuable cross-border insight for companies migrating to multi-language or multi-region architectures.

The agency excels on large-scale projects: migrations of sites with millions of pages, consolidation of international domains, and redesigns of complex technical architectures. Its strong technical background — with teams dedicated to technical SEO, data engineering, and development — makes it an ideal partner for migrations requiring close coordination between SEO and development teams.

Peak Ace has notably managed migrations for major European accounts in retail, travel, and finance, with traffic preservation challenges at considerable volumes.

4. Eskimoz — Paris

Eskimoz is one of France’s largest SEO agencies with more than 1,000 clients served. Its size and resources allow it to deploy dedicated teams for high-volume migration projects. The agency offers comprehensive support: semantic and technical pre-migration audit, content strategy adapted to the new architecture, and post-migration follow-up.

Its strength lies in its ability to handle large-scale migrations thanks to industrialized processes and proprietary crawl and analysis tools. Eskimoz is also certified Google Premier Partner, reflecting a level of expertise recognized by Google.

The agency is particularly suited for mid-size companies and large accounts looking for a partner capable of quickly mobilizing significant resources for a migration project.

5. Noiise — Lyon / Paris

Noiise is a historic SEO agency in France, born from the merger of Open Linking and 1ère Position in 2019. With more than 80 team members spread between Lyon and Paris, the agency has significant resources for complex migration projects.

Its experience accumulated over more than a decade has allowed it to work on numerous redesigns and migrations for SMBs as well as large accounts. The agency stands out through its balanced approach between technical SEO, content strategy, and link building, enabling it to address the three critical pillars of a successful migration: technical preservation, editorial optimization, and domain authority maintenance.

Its size allows it to assign experienced project managers and domain-specialized consultants to each migration.

6. Jloo — Paris

Jloo serves approximately 200 clients with particular expertise in e-commerce migrations. The agency has conducted thorough technical comparisons between platforms (Shopify vs Prestashop vs Magento), giving it in-depth knowledge of each CMS’s specifics — a decisive asset during a migration.

Its methodical approach results in a documented migration plan with exhaustive URL mapping, comparative analysis of SEO features between source and target platforms, and prioritized recommendations. The agency is particularly relevant for e-commerce merchants migrating from one solution to another who need a partner that understands the SEO implications of each technical choice.

7. Semji — Lyon

Semji positions itself at the intersection of SEO and AI technology, with a proprietary platform that analyzes content and recommends optimizations based on SERP data. In a migration context, this hybrid agency-platform approach enables simultaneous auditing and optimization of existing content.

The agency is particularly relevant for migrations accompanied by an editorial overhaul: consolidating cannibal pages, restructuring internal linking, and updating strategic content. Its platform identifies high-SEO-value content to preserve as a priority and content to merge or remove, streamlining the migration plan.

8. SmartKeyword — Paris

SmartKeyword combines a deep semantic approach with proprietary data tools to support site migrations. The agency stands out through its ability to model the ideal semantic architecture of the target site before migration, based on search intent analysis and thematic clusters.

This approach is particularly suited for migrations involving site architecture restructuring: category overhauls, new semantic silo creation, and internal linking optimization. SmartKeyword also offers post-migration tracking focused on semantic position monitoring and rapid detection of visibility losses by cluster.

Why a Site Migration Requires an SEO Expert

The Risks of a Poorly Managed Migration

A site migration represents one of the most critical moments for organic search. According to an Ahrefs study, more than 60% of poorly prepared migrations result in significant organic traffic loss, sometimes exceeding 30%, with recovery that can take 6 to 12 months — or may never fully occur.

The most common mistakes include:

Missing or incorrect redirects: every URL that changes must have a 301 redirect to its exact equivalent
Internal linking loss: broken internal links after migration destroy internal PageRank flow
Unintentional content changes: modified texts, title tags, and meta descriptions trigger a Google reassessment
Indexation issues: residual noindex tags, blocking robots.txt, or outdated XML sitemap
Loss of structured data: unmigrated Schema.org markup reduces visibility in rich results and AI responses

The GEO Challenge in a Migration

In 2026, a poorly managed migration doesn’t just affect positioning in Google’s classic results. It also impacts visibility in generative search engines like ChatGPT, Perplexity, and Google AI Overviews. Generative AIs index and memorize source URLs: if these return 404 errors after migration, content is gradually de-indexed from AI knowledge bases.

A migration-specialized SEO expert ensures that E-E-A-T signals are preserved, structured data is correctly transposed, and URLs cited by AIs continue to function via appropriate redirects. To understand how AIs select their sources, refer to our guide on techniques to appear on ChatGPT.

The Different Types of Migrations

Domain Migration

Changing the domain name (e.g., old-site.com → new-site.com) is the riskiest migration because it involves a complete transfer of domain authority. Google must reassociate all trust signals — backlinks, history, authority — with the new domain. This type of migration requires rigorous use of the Change of Address tool in Google Search Console and an exhaustive 301 redirect plan.

CMS / Platform Migration

Changing platforms (e.g., Prestashop to Shopify, WordPress to headless) typically modifies the URL structure, page templates, and sometimes the content itself. The difficulty lies in mapping between old and new URLs, which often follow radically different logic depending on the CMS.

HTTP to HTTPS Migration

Although now standard, switching to HTTPS remains a full-fledged technical migration. Every HTTP URL must be redirected to its HTTPS equivalent, and all internal resources (images, scripts, CSS) must be served over HTTPS to avoid mixed content.

Redesign with Architecture Change

Restructuring the site architecture — merging categories, modifying semantic silos, changing navigation depth — is often the most impactful migration for SEO. It modifies the internal PageRank distribution and can affect the positioning of hundreds of pages simultaneously.

Site Merger or Separation

Consolidating multiple domains into one (or vice versa) involves complex strategic choices: which domain to keep, how to handle duplicate content between source sites, and how to redistribute backlink authority.

Selection Criteria for an SEO Migration Agency

Essential Competencies

Choosing an SEO agency for a migration should be based on criteria specific to this type of project:

Documented migration experience: case studies with before/after traffic data
Advanced technical mastery: crawling, log analysis, large-scale redirect management
Multi-CMS knowledge: understanding of both source and target platforms
Structured methodology: phased process with milestones and validation criteria
Post-migration monitoring capability: tools and responsiveness to detect and correct anomalies quickly
GEO expertise: preserving visibility in generative AI search engines

Warning Signs

Certain indicators should raise red flags when choosing a migration agency:

No specific migration case studies with quantified results
No pre-migration audit phase in the proposal
No structured post-migration monitoring mentioned
Promising “migration with absolutely no traffic loss” — a migration always involves an adjustment period, and an honest partner explains this clearly
No coordination planned with the client’s development teams

Budgets and Return on Investment

Price Ranges for an SEO Migration

Budgets vary based on project complexity, number of URLs to migrate, and desired support level:

Migration Type	Estimated Budget	Project Duration
Simple migration (< 500 URLs)	€5,000 – €10,000	1 to 2 months
Medium migration (500 – 5,000 URLs)	€10,000 – €25,000	2 to 4 months
Complex migration (5,000 – 50,000 URLs)	€25,000 – €50,000	3 to 6 months
E-commerce migration (50,000+ URLs)	€50,000 – €100,000+	4 to 8 months
Post-migration monitoring (recurring)	€2,000 – €5,000/month	3 to 6 months

The Cost of Inaction

Not investing in specialized SEO support during a migration can cost significantly more than the agency’s fee. A 30% loss of organic traffic on a site generating €100,000 in monthly revenue via SEO represents a loss of €360,000 per year — not counting recovery costs. Relative to the budget of a specialized agency, the ROI of migration support is typically greater than 5x.

SEO Migration Checklist: Key Steps

Phase 1 — Pre-Migration Audit

Complete crawl of the existing site (URLs, HTTP statuses, internal linking)
Export of organic positions and traffic by URL
Backlink inventory by landing page
Audit of existing structured data
Identification of high-SEO-value pages (traffic, positions, backlinks)

Phase 2 — Preparation

Comprehensive URL mapping: old URL → new URL
301 redirect plan creation
New architecture validation (silos, depth, internal linking)
New XML sitemap preparation
New robots.txt configuration

Phase 3 — Launch

301 redirects go live
New sitemap submission in Google Search Console
Use of Change of Address tool (if domain change)
Accessibility verification of all strategic pages
Structured data testing on key pages

Phase 4 — Post-Migration Monitoring

Daily tracking of crawl errors in Google Search Console
Position monitoring on strategic keywords
Server log analysis to detect 404s and redirect loops
Organic traffic tracking by segment (brand, non-brand, categories)
Visibility check in AI search engines (Perplexity, ChatGPT, Google SGE)

Choosing an SEO agency for a migration is a strategic investment whose impact is measured over several years. In a context where AI search engines are redefining content discovery, selecting a partner who masters both technical SEO and GEO ensures visibility across all search channels — classic and generative. To deepen your understanding of content optimization strategies for generative AI, it is essential to structure your approach around the trust criteria that determine source selection by language models. After a successful migration, work on your AI visibility with the best SEO agencies for AI Overviews and strengthen your link profile with the best link building agencies.