Organic search is usually the cheapest channel a business owns and the slowest one to build. An SEO agency is the supplier you hire when you want that channel worked on continuously, by people who do it every day, instead of squeezing it between other jobs. The agencies listed on this page offer that service, and the city and country pages further down narrow the list to a single market. Before you contact anyone, it pays to know what the work actually consists of, what you are entitled to ask for, and what a sane commercial arrangement looks like.
What an SEO agency actually does
SEO work splits into four streams, and they rarely sit with the same person. Knowing which stream your site needs is most of the buying decision.
- Technical. Crawlability, indexation control, rendering of JavaScript pages, load behaviour on real devices, internal link structure, canonical and hreflang handling, structured data. This is where a rushed migration or a stray noindex tag removes traffic overnight.
- Content. Query research, mapping queries to pages so two of your own URLs never chase the same term, briefs that writers can follow, and rewrites of pages that already rank but collect no clicks.
- Off-site. Earning links and brand mentions through digital PR, partnerships, original data, and industry listings. How an agency acquires links is the single most revealing question you can ask.
- Measurement. Search Console and analytics wired up correctly, rank tracking segmented by intent rather than a vanity list, and a monthly document that explains what changed and what caused it.
A team that sells only one of these streams is not doing anything wrong, but you need to know which one you are buying. A content production shop will not fix a rendering fault, and a technical consultancy will not write your category copy. When paid and organic have to move together under one owner, a digital marketing agency is often the closer fit; when the gap is editorial capacity, look at content marketing agencies instead.
Questions that separate a specialist from a reseller
A large slice of the SEO market is white labelled. Work is sold by one company, delivered by another, and the buyer never learns who touched the site. That is not automatically bad, but it has to be disclosed, because it decides who answers the phone when rankings drop. Put these to every shortlisted supplier:
- Who does the work, by name, and how many other accounts does that person carry?
- Is any part of delivery subcontracted, and to whom?
- Can you show an audit written for a client of my size, with the name redacted and the reasoning intact?
- How are links acquired? A team that cannot describe its outreach in plain language is buying placements.
- Which of my pages would you leave alone in the first quarter, and why?
- What do you need from my developers, and what is your plan when they are busy?
The last two carry more weight than they appear to. A supplier who wants to rewrite everything on day one has not read your analytics. A roadmap that assumes unlimited engineering time will stall in month two, and both sides will blame each other for the delay.
Access and ownership, settled before the first invoice
Get this in writing while everyone is still friendly. Analytics and Search Console properties live in accounts your company owns, with the agency added as a user, never the reverse. Content is published in your CMS under a license you keep. The tag container belongs to your workspace. Reporting dashboards can be theirs; the data sources behind them cannot. Prising a Search Console property out of a former supplier is slow, and the historical data you lose in the process is worth more than the argument.
Retainer, fixed project, or performance deal
| Model | Suits | What to watch |
|---|---|---|
| Monthly retainer | Sites that need continuous technical, editorial and off-site work under one roadmap | Deliverables written as outputs, not as hours; a notice period you can actually use |
| Fixed-scope project | An audit, a migration plan, a one-off information architecture rebuild, or a market entry | Who implements the recommendations, and whether implementation is priced separately |
| Performance or revenue share | Mature ecommerce and lead sites with clean attribution and stable margins | Which conversions count, what happens to brand traffic, and how long the agency keeps earning after the contract ends |
Performance pricing sounds risk free and rarely is. It pushes the supplier toward whatever converts fastest, which is usually your brand terms and your existing customers, not the market you were trying to reach. If you use it, exclude branded queries from the calculation and agree the exclusion in the contract.
Writing a brief that produces comparable proposals
Most proposals are impossible to compare because every agency was answering a different question. A brief of one page fixes that. Include the commercial goal in your own words, the markets and languages involved, your platform and who can deploy to it, whether content is written in house, what you tried before and why it stopped, any legal or regulatory limits on claims, and a budget band. Naming a band is not weakness. It stops three of the five proposals from being irrelevant and saves a fortnight.
If you would rather write that once and let matching agencies respond, send your brief through Edvido and compare what comes back.
Reading the proposals side by side
Score every proposal on the same five columns: quality of the diagnosis, what is delivered each month, which named people deliver it, reporting cadence and format, and exit terms. The diagnosis column decides most decisions. An agency that inspected your site before pitching will describe a problem you recognise; one that did not will describe the industry.
Treat a promise of specific positions by a specific date as a disqualifier. Nobody controls the ranking system, and a supplier confident enough to guarantee output is planning to hit the number with terms nobody searches for. What a serious proposal does contain is a sequence: what gets fixed first, what that should move, and how you will both know.
Where SEO budgets get wasted
- Starting a retainer while the site is mid-replatform. Wait, or hire the migration work as its own project.
- Commissioning articles that compete with pages you already rank with, then wondering why both slipped.
- Judging results on the agency dashboard instead of clicks, enquiries and revenue in systems you control.
- Cancelling before anything could have surfaced. Technical fixes show up quickly, new content and authority work take quarters.
- Splitting one site between two suppliers with nobody owning the roadmap, which produces conflicting changes and an unarguable blame loop.
Online retailers face an extra version of the last point, because catalogue structure, faceted navigation and feed quality straddle the line between search and merchandising. If that is your situation, weigh specialists against eCommerce agencies that already work inside your platform.
Hiring in a market you do not operate in
Result pages are localised, competitors differ street by street, and language is only part of it. A supplier in the target market reads the result page the way a customer there does, knows which directories and publishers carry weight, and writes copy that does not feel translated. A supplier at home is easier to manage and cheaper to meet. Many buyers resolve it by keeping strategy and technical work central and contracting local partners for content and outreach. The city and country pages below this section list agencies market by market, for example SEO agencies in London or SEO agencies in New York.
Browse SEO agencies by location and compare verified agencies in each market.
By region
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Related categories
digital marketing agencies · content marketing agencies · eCommerce agencies
Frequently Asked Questions
How long before organic traffic moves?
Indexation and technical faults can resolve within days of a fix. Content and authority work moves on a scale of quarters, and competitive commercial terms take longer still. Judge an agency in the first months on the quality of its diagnosis and the pace of implementation, not on rankings.
Is a small agency riskier than a large one?
The risk profiles differ. A small team gives you senior attention and disappears if one person leaves. A larger firm has cover and process, and may staff your account with its least experienced people. Ask who is assigned either way, and how that changes after the first quarter.
Should the agency write the content as well?
It works when the agency has genuine editorial capacity and your subject can be researched from outside. In technical or regulated fields, the stronger arrangement is usually agency briefs plus your own experts, with the agency editing for search and the expert owning accuracy.
What does an SEO audit actually give me?
A ranked list of what is limiting the site, each item tied to evidence and to an owner. An audit that lists every warning a crawler produced, without deciding what matters, has transferred the analysis back to you.
Can I bring this in house later?
Yes, and a good supplier plans for it. Keep documentation, source files and access in your systems from the start, and ask early what a handover would include. Agencies that resist the question are telling you how the relationship ends.
How do I check references properly?
Ask for a client who left, not only for current ones. Then ask the reference what went wrong at some point and how the agency behaved when it did. Every engagement has a bad month, and the answer to that question predicts your own experience better than a case study.
