SaaS & B2B × Retainer Work
Best SaaS & B2B AI Agencies for Retainer Work (September 2026)
SaaS & B2B AI agencies with verified retainer client evidence — ranked by depth of documented work, then editorial quality.
Each listed agency documents retainer engagements on its own site or in a published case study; the model is never inferred from a service list.
Ranked agencies for retainer clients
Rankings updated · Newest review
Dublin, Ireland
Client evidence: 20 documented clients overall
Best for: Irish and European SMEs and founders buying a whole product build, with AI as one layer inside it rather than the whole engagement.
ontolux
#2Berlin, Germany
Client evidence: 13 documented clients overall
Best for: German public bodies, broadcasters and publishers that need tagging and search over large German-language text collections.
OstraconAI
Verified: the agency confirmed ownership from a company email address, and the listing passed editorial review#3Helsinki, Finland
Client evidence: 11 documented clients overall
Best for: Nordic marketing and sales teams that want AI tools built into HubSpot, Teams or Microsoft 365 and their own staff trained to run them.
Madrid, Spain
Client evidence: 11 documented clients overall
Best for: Consumer-facing brands and large operators in Spain evolving a digital product over years, with AI added into an existing workflow.
Redkiwi
#5Rotterdam, Netherlands
Client evidence: 9 documented clients overall
Best for: Dutch consumer brands and B2B suppliers buying a website, webshop or campaign where generative AI speeds up content production.
Found
#6London, United Kingdom
Client evidence: 8 documented clients overall
Best for: UK consumer brands in retail, insurance and hospitality that want AI applied inside paid search, SEO and campaign data.
Rotterdam, Netherlands
Client evidence: 8 documented clients overall
Best for: Mid-sized Dutch companies that want ERP, CRM and finance data in one managed Power BI environment before any AI build.
Budapest, Hungary
Client evidence: 7 documented clients overall
Best for: Banks, retailers and utilities that want a propensity or next-best-offer model on their own data, scored on a business rate.
Berlin, Germany
Client evidence: 7 documented clients overall
Best for: Product owners adding AI to an app that already has users, rather than starting from a model.
QED Software
#10Warsaw, Poland
Client evidence: 7 documented clients overall
Best for: Data-rich firms and startups with a detection, vision or forecasting problem suited to a research-led team.
ClickSlice
#11London, United Kingdom
Client evidence: 6 documented clients overall
Best for: UK online retailers that want an existing SEO campaign extended to how ChatGPT, Gemini and Perplexity recommend brands.
Warsaw, Poland
Client evidence: 5 documented clients overall
Best for: Small manufacturers, contractors and agencies automating invoice, document and CRM workflows on a Make.com or Zapier stack.
NOVOS
#13London, United Kingdom
Client evidence: 5 documented clients overall
Best for: Consumer e-commerce brands that want to be named in AI answers through SEO and digital PR, with share-of-answer tracking.
Dublin, Ireland
Client evidence: 4 documented clients overall
Best for: Software vendors and public bodies modernizing an Azure platform, where new AI has to fit systems already carrying live volume.
Contiamo
#15Berlin, Germany
Client evidence: 4 documented clients overall
Best for: German municipal utilities, housing companies and consumer brands adding GPT-based assistants to customer service and content work.
Flobotics
#16Warsaw, Poland
Client evidence: 3 documented clients overall
Best for: Operations teams that want automation bought against a payback number, especially in healthcare revenue cycle.
Boldare
#17Amsterdam, Netherlands
Client evidence: 3 documented clients overall
Best for: Consumer-facing businesses adding an OpenAI-backed chatbot or generated content to a web platform Boldare builds or runs.
Warsaw, Poland
Client evidence: 3 documented clients overall
Best for: Fintech and proptech product teams that want LLM agents or AI forms built into a JavaScript platform by a small senior team.
Intunio
#19Gothenburg, Sweden
Client evidence: 3 documented clients overall
Best for: Industrial manufacturers that want AI and interfaces designed into everyday work, with the price list published up front.
Inbold
#20Oslo, Norway
Client evidence: 3 documented clients overall
Best for: Consumer and healthcare brands needing campaign and compliance production at Nordic scale, with AI used in the making.
wukonig.com
#21Graz, Austria
Client evidence: 3 documented clients overall
Best for: B2B and industrial firms that want to be named in AI answers and will fund a measured, ongoing program.
VisualLabs
#22Budapest, Hungary
Client evidence: 3 documented clients overall
Best for: Field-service and distribution businesses on Microsoft Dynamics that want their data and processes fixed before adding Copilot or agents.
Gemmo AI
#23Dublin, Ireland
Client evidence: 3 documented clients overall
Best for: Financial-services teams with their own engineering who need a machine-learning bench for the experiment-and-prototype stage.
Madrid, Spain
Client evidence: 3 documented clients overall
Best for: Early-stage founders in Spain who need a product built quickly and will scope any real model work separately.
About this list
For software and B2B companies most retainers here fall on either side of the product boundary. Inside the product: Mobile Reality built the Nomis Index pricing and deposit-simulation MVP for Nomis Solutions in Node and React with post-update support, and CBRE Zone for CBRE Spain, neither with AI, while its open-source MDMA framework for LLM-generated forms is said to be deployed in fintech and proptech without a named client. Intunio has worked with Emerson's Rosemount Tank Radar on the user experience of its measurement software since 2021 and built Electrolux Shape from scratch in 2018, design-system retainers; model work goes to partners by its own account. Around the go-to-market: OstraconAI built Singa's inbound lead pipeline on n8n and Gemini, live in week three; Redkiwi launched Verder Liquids in 24 countries and 28 languages with quote requests up 168%; wukonig.com ran a prompting program for TCM International's sales team. Data Analytics runs managed BI, a 40-million-row environment at Deloitte, with no model in production. NOVOS's case studies are consumer e-commerce, and the curator calls B2B its weaker fit. Some retainers sit in back-office operations instead: Flobotics' bots move data between electronic health record systems for DocPlanner at more than 10,000 processes a month, 98% handled automatically.
Decide which boundary the retainer crosses. A product retainer has to work inside your release train, so ask who reviews pull requests and whether the agency's engineers or a partner's own the model; Mobile Reality's team page lists no data scientist. A go-to-market retainer runs on accounts and workflows, so ask who owns them after the engagement, the question the curator puts to OstraconAI directly.
Intro by Gabor Kiss, curator · How we rank
Expert Insight
Why SaaS & B2B experience matters
Evaluation infrastructure—The difference between a demo and a durable feature is an eval suite: test sets, regression checks on prompt changes, quality metrics tied to user outcomes. Specialists build it alongside the feature; without it, every model update is a gamble shipped straight to production
Unit-economics engineering—Per-request model costs decide whether your feature has a margin. Specialists design cost ceilings in from the start—model routing, caching, context trimming—instead of discovering at scale that the assistant costs more than the seat
Handover quality—Your engineers inherit this code. Specialists deliver documented pipelines, reproducible evals, and infrastructure your team can run; agency-shaped black boxes turn into unmaintainable dependencies the day the contract ends
Product-not-project thinking—AI features need iteration loops after launch: feedback capture, failure review, prompt and model updates. Specialists set up that loop and a sane retainer for it; project shops ship the feature and leave you with version one forever
Frequently asked questions
24 agencies in our directory combine verified retainer client evidence with documented SaaS & B2B work. The current top-ranked are Square Root Solutions, ontolux, OstraconAI — ordered by depth of documented client evidence, then our editorial scoring (portfolio quality, credibility, completeness); placement is never paid.
Published rates across this page's agencies run €20–400 per hour (median ~€65). Project totals depend on scope — the rate index at /rates breaks the computed bands down by region, country and team size.
Every agency here documents retainer work on its own site or in a published case study, describing the engagement structure rather than a service-list claim. We never infer the model from portfolio tone, so this list only contains agencies that operate retainer engagements deliberately.
2 of the agencies on this page document an embedded / team-extension working model. See the team-extension page for the full verified list, or check the engagement chips on individual profiles.