The best GTM engineering agencies with Clay and HubSpot experience are the firms that can show both partner directories and explain, in writing, how a Clay row becomes a HubSpot record without creating a duplicate. Eleven firms are compared below: six appear in both Clay's and HubSpot's partner directories, and five appear in Clay's directory with a HubSpot claim made on their own pages.
Best GTM Engineering Agencies Clay HubSpot Experience: The Short Answer
- Listed in both directories (alphabetical, not ranked): Aptitude 8, FullFunnel, LeanScale, Peakora, RevPartners and Understory. RevPartners is the only one of the eleven at the top tier of both (Clay Elite Studio and HubSpot Elite), which matches its own claim.
- Clay directory plus a HubSpot claim on the firm's own pages: Enablement, Frontal AI, Levver, Sculpted and Skydog Ops. Their HubSpot evidence is labelled as their own words, not a directory record.
- Clay's "CRM Enrichment - Hubspot" tag does not separate firms. It appears on 16 of the 19 Clay listings compared for this page, and Aptitude 8, a HubSpot Elite partner, does not carry it. The HubSpot directory, and its Custom Integration and Data Migration accreditations, say more.
- The deciding test is the write-back. HubSpot states that companies created through the API are not deduplicated by domain, and Clay's update action needs a HubSpot record ID. An agency that cannot describe its lookup-before-create step will fill your CRM with duplicate companies. The Write-Back Contract below lists the seven decisions to get in writing.
The Operating System a Clay and HubSpot Agency Builds
A Clay and HubSpot engagement is a loop with four stages. Clay does the research and scoring; HubSpot holds the record, runs the sequence and reports the pipeline. Each stage needs a named owner on your side, a rule for passing work to the next stage, and a line between what runs automatically and what a person approves.
| Stage | Clay side | HubSpot side | Owner after handover | Handoff rule to the next stage | Automated | Human-reviewed |
|---|---|---|---|---|---|---|
| 1. Data and signal | Import accounts from HubSpot or a source, enrich, score against written ICP rules | Company and contact records, the fields Clay may write | RevOps | A row passes only when it meets the fit score and has a dated signal and a source link | Import, enrichment, scoring, lookup against existing records | Which signals count; field ownership; a weekly sample of false positives |
| 2. Campaign | Build the first line and segment from the enriched row | Static list or sequence enrolment for the matched contact | Marketing operations with the SDR lead | A contact enters a sequence only when it has an owner and is not in an open deal | List adds and enrolment for approved plays | Copy built on an inference; first send of any new segment |
| 3. Sales handoff | Pass the trigger, its date and the source link into named properties | Lead or lifecycle change, owner assignment, task | Sales manager | The rep accepts or returns the record with a reason code within an agreed time | Assignment and the alert with its context | Accept or return; any backwards lifecycle move, because HubSpot's defaults only move forward |
| 4. Pipeline measurement | Stamp the signal type and play on the record when it is written | Deal source properties and pipeline reports | RevOps | Sourced and influenced pipeline are defined before the first report runs | Source stamping and report refresh | The definitions; a monthly keep-or-retire review of each play |
Two rules sit under the table. First, Clay writes into HubSpot through the integration's create, update and association actions, so every arrow from left to right in the table is a write that needs a match rule. Second, the owner column is your staff, not the agency's; if no one on your side can fill it, the engagement is a rental rather than a build. The guide on moving a lead from MQL to SQL sets out accept-and-return rules that transfer directly to stage 3.
Lead Seeker, which publishes this page, works at stage 1: you describe the ICP, it watches public buying signals, Lead Compass turns them into a source-backed brief and a search-ready prompt, and each search returns a verified dossier that syncs to Salesforce or HubSpot. The walkthrough of how Lead Seeker works shows that flow. It is an input an agency can wire into the loop, not an agency, so it is not a row in the rubric. Teams comparing Clay itself with other research tools can start with the best Clay alternatives for prospect research 2026.
Decision Framework: The Two-Directory Check
Every firm below is scored on the same five columns. The Two-Directory Check is the first three: what Clay's directory says, what HubSpot's directory says, and whether the firm holds the HubSpot accreditations closest to integration work.
- Clay tier. The firm's tier on Clay's Solutions Partner Directory: Elite Studio, Studio, Advanced Artisan, Artisan, in that order.
- HubSpot evidence. The tier on HubSpot's Solutions Directory where a listing was matched to the firm (Solutions Partner, Gold, Platinum, Diamond, Elite, in ascending order). Where no listing is cited, the cell quotes the firm's own HubSpot claim and labels it as such.
- Integration accreditations. Whether the HubSpot listing shows the Custom Integration and Data Migration accreditations.
- Clay listing price and minimum. The monthly band and minimum engagement on the firm's Clay listing.
- Status and relationship. Acquisitions on record and any relationship to the author or publisher.
How to weigh the columns: HubSpot awards tier points per US$100 of monthly recurring revenue a partner sources, assists or manages, and Elite partners must hold at least 80% average gross revenue retention over 12 months. Fact: a HubSpot tier measures software revenue and retention. Inference: it shows a firm has many HubSpot customers, not that it can design a Clay write-back. The integration accreditations are the closer evidence for that, and the Write-Back Contract is the direct test.
Then two questions narrow the eleven to two or three. Is your gap in HubSpot or in Clay? If the CRM data model, objects or migrations are the problem, weight the HubSpot columns and the accreditations. If HubSpot is sound and you need signals, enrichment and plays, weight the Clay tier and ask for a write-back walkthrough. Who will own stage 1 and stage 4 after handover? If nobody will, choose a firm that runs the system and accept the ongoing fee.
Evidence Table: Eleven Firms on One Rubric
Tiers, accreditations, prices and minimums in both tables are an October 2026 snapshot. Quoted phrases are the firms' own words; nothing in the tables is an outcome claim.
| Firm | Clay tier | HubSpot evidence | Integration accreditations | Clay listing price and minimum | Status and relationship |
|---|---|---|---|---|---|
| Aptitude 8 | Artisan | HubSpot directory: Elite (259 reviews) | Custom Integration, Data Migration | No price band; 3-month minimum | No relationship |
| FullFunnel | Elite Studio | HubSpot directory: Platinum | None shown | $5k+ a month; 1-month minimum | No relationship |
| LeanScale | Studio | HubSpot directory: Platinum | None shown | "Any budget"; 3-month minimum | No relationship |
| Peakora | Studio | HubSpot directory: Gold | None shown | "Any budget"; 3-month minimum | No relationship |
| RevPartners | Elite Studio | HubSpot directory: Elite (528 reviews) | Custom Integration, Data Migration | "Any budget"; 3-month minimum | Acquired by Walker Sands, announced June 10, 2026; no relationship |
| Understory | Advanced Artisan | HubSpot directory: Solutions Partner | None shown | "Any budget"; 6-month minimum | No relationship |
| Firm | Clay tier | HubSpot evidence (firm's own words) | Integration accreditations | Clay listing price and minimum | Status and relationship |
|---|---|---|---|---|---|
| Enablement | Studio | "implemented 52 Clay accounts and over 85 HubSpot instances" | No HubSpot listing cited | $5k+ a month; 3-month minimum | No relationship |
| Frontal AI | Elite Studio | A customer pipeline result "built inside their HubSpot" (vendor-reported) | No HubSpot listing cited | $5k+ a month; 3-month minimum | Renamed from ColdIQ Agency; no relationship |
| Levver | Studio | "We're a Hubspot platinum partner"; "three of the largest HubSpot accounts in the world" | No HubSpot listing cited | "Any budget"; 3-month minimum | No relationship |
| Sculpted | Advanced Artisan | A 30-day "CRM Clean-up Sprint" for HubSpot data | No HubSpot listing cited | $5k+ a month; 3-month minimum | No relationship |
| Skydog Ops | Studio | "G2's #1 Salesforce firm and #2 HubSpot firm" | No HubSpot listing cited | $10k+ a month; 3-month minimum | No relationship |
What each group is for
HubSpot-first firms that also build in Clay (Aptitude 8, RevPartners). Fact: both are HubSpot Elite partners with the Custom Integration and Data Migration accreditations, and both list custom API integrations among their HubSpot services. Aptitude 8's Clay listing describes it as "a technical solutions partner that helps companies scale operations and customer experience on HubSpot"; RevPartners' Clay page offers to "Connect Clay directly to HubSpot and your core tech stack for seamless, bi-directional revenue data flow". RevPartners' HubSpot listing states "Implementations starting at $1,5k". Inference: these fit when the HubSpot data model needs work as well as the Clay layer. For RevPartners, ask who staffs your account after the Walker Sands acquisition.
Clay-first studios with a HubSpot practice (FullFunnel, LeanScale, Peakora). Fact: all three sit at Studio tier or above on Clay and Platinum or Gold on HubSpot, and none of their HubSpot listings shows an accreditation. FullFunnel has the shortest minimum in the table (one month) at $5k+ a month; Peakora describes itself as a GTM partner in the DACH region and works in English, German and French. Inference: these fit when HubSpot is already in reasonable order and the gap is signals, enrichment and plays; ask each for the Write-Back Contract before signing.
Integrated agency (Understory). Fact: Understory is an Advanced Artisan on Clay and a base-tier Solutions Partner on HubSpot, asks for six months, and describes Clay as "a central hub to build and enrich new outbound, and paid media campaigns, enrich existing lists from your CRM, and create new ones". Understory also publishes a roundup of GTM engineering agencies in which it places itself first. Inference: this fits when paid media and outbound must run as one programme; it is the weakest HubSpot evidence among the six.
Clay partners whose HubSpot evidence is their own claim (Enablement, Frontal AI, Levver, Sculpted, Skydog Ops). Fact: each makes a specific HubSpot statement on its Clay listing or home page, quoted in the table. Sculpted's pre-work asks clients to "Provide Clay + HubSpot credentials" and to upload sample records; Frontal says it builds "inside your stack, HubSpot, Salesforce, Clay, and hand it over so your team owns it". Inference: these may be strong HubSpot builders, but the evidence is self-reported, so ask for the HubSpot directory listing and a reference customer whose portal you can discuss.
Percepture, where I am President, is not a row because it does not present itself as a Clay build studio. Its B2B intent data services cover signal mapping, campaign activation and CRM workflows with a human review step, which makes it a stage 1 and 2 option for teams whose gap is the signal itself. Its explainer on using intent data to identify sales qualified leads covers the qualification logic that feeds stage 3. For a wider set of firms that includes non-HubSpot shops and run-for-you outbound, see the roundup of the best gtm engineering agencies and consultants for b2b saas.
Three claims to check before you shortlist
- Elite Studio counts disagree. Frontal's Clay listing says "1 of 5 Clay Elite Studio Partners worldwide", its home page says 1 of 4, and Clay's directory lists six Elite Studios (FullFunnel, Frontal AI, Go Nimbly, Growth Engine X, RevPartners and The Kiln). Ask which programme and which date the claim refers to.
- The Clay tag is not HubSpot evidence. "CRM Enrichment - Hubspot" sits on 16 of the 19 Clay listings compared, including firms with no HubSpot listing cited. Check HubSpot's own directory.
- "Partner" has five HubSpot tiers. Understory and Elite firms are both HubSpot Solutions Partners; the tier and the accreditations are what differ. Ask for the listing URL rather than the badge.
The Write-Back Contract: Seven Decisions Before Anything Writes to HubSpot
This is the implementation section. Each line is a decision the agency makes during the build, whether or not it tells you. Put all seven in the statement of work, with the HubSpot fact or Clay setting that makes each one necessary.
| Decision | What has to be agreed | The platform fact behind it |
|---|---|---|
| 1. Match key per object | Contacts match on email; companies match on primary domain or a custom unique-value property; deals match on record ID | HubSpot dedupes contacts by email and companies by domain, but "companies created through API will not be deduplicated by the Company domain name property", including third-party sync apps |
| 2. Lookup before create | Every create is preceded by a Look up object step, and the row branches: update if found, create if not | Clay's Update object action requires the HubSpot Object ID; Look up object returns up to 200 matches (10 by default) |
| 3. Domain normalisation | Whether subdomains are kept or reduced to the root domain, the same way in lookups and writes | Clay reduces domains to the root by default in both create and lookup (shop.example.com becomes example.com) unless the subdomain setting is turned on |
| 4. Overwrite authority | Which HubSpot properties Clay may write, and whether a blank can overwrite a value | Clay's "Ignore blank values" is on by default, so blanks leave HubSpot values alone; turning it off lets blanks overwrite |
| 5. Associations | Which contact-to-company and lead associations Clay creates, and in what order | Clay's Create association action needs both record IDs, so the company must exist or be found before the contact is linked |
| 6. Lists and sequences | Which static lists Clay adds to, and who approves sequence enrolment | Clay can add records only to static lists, because HubSpot recalculates active lists from filters; the two sequence permissions are off by default when HubSpot is connected |
| 7. Lifecycle and ownership | Who may move lifecycle stages, how an owner is assigned, and what happens to a returned lead | HubSpot's default lifecycle updates "will only move the stage forward"; Clay's Find owner action is more reliable by owner ID than by email |
Two plan facts belong in the same document. Clay's pricing table includes CRM integrations on its Growth and Enterprise plans, not on Free or Launch, and Clay's pricing FAQ lists Growth from $495 a month. On the HubSpot side, Clay's documentation notes that custom object permissions are available on HubSpot Enterprise portals only, so a build that writes to custom objects needs Enterprise. The object-identity questions behind lines 1 to 3 are covered in more depth in the guide to crm implementation agency sales marketing service data alignment.
A worked example
The example below is invented to show the sequence; the company, people and dates are not real, and no outcome figures are implied.
Larkspur Ledger (invented) is a Series B SaaS company on HubSpot Sales Hub Professional with a RevOps manager, four account executives and two SDRs. It shortlists one HubSpot-first firm and one Clay-first studio, and asks both to walk through the Write-Back Contract against ten of its own company records, three of which have subdomain websites.
- Week 1. The RevOps manager writes the match-key line: companies by primary domain, contacts by email, and a custom unique-value property for the legacy account ID. Both firms are asked what happens to the three subdomain records. One answers with the Clay setting and a branch for each case; the other answers "Clay handles it". Larkspur hires the first.
- Weeks 2–4 (stages 1 and 2). The agency builds the enrichment table with a lookup step before every create. The RevOps manager approves the list of properties Clay may write and keeps "Ignore blank values" on. Marketing approves the first two plays and the static lists they feed.
- Weeks 5–6 (stage 3). The sales manager writes the accept-or-return rule and the reason codes before assignment is switched on, and names who may move a returned lead backwards.
- Weeks 7–8 (stage 4). Source properties are stamped on each write and the pipeline-by-source report is built in HubSpot. The RevOps manager runs a duplicate check on companies created during the build and signs off the handover.
The order is the point: match keys and overwrite rules before the first write, human approvals written before automation is switched on, and measurement inside the CRM the reps already use.
When a Clay and HubSpot Agency Is the Wrong Hire
If HubSpot itself is the problem (lifecycle stages nobody agrees on, duplicate companies already in the thousands, objects that do not match how you sell), fix the CRM first with a HubSpot implementation partner; a Clay build will write faster into the same mess. If you are on Clay's Free or Launch plan and do not plan to move to Growth, the CRM integration is not available and an agency will route data through exports or another tool. If your volume of target accounts is small enough for one person to research by hand, a data tool and a written playbook may cost less than any minimum above. And if contracts or regulators restrict where contact data can be processed, settle that before the enrichment layer is designed, because the data providers are chosen in week one.
Frequently Asked Questions
Do I need a Clay agency if I already have a HubSpot partner?
Not always. If your HubSpot partner holds the Custom Integration accreditation and can describe a lookup-before-create step, it may be able to own the Clay write-back. Aptitude 8 and RevPartners are examples of HubSpot Elite partners that also hold Clay listings. If your partner only does onboarding and marketing setup, a Clay studio will build the signal and enrichment layer, and the two firms need one written Write-Back Contract between them.
Which Clay plan do I need to sync Clay with HubSpot?
Clay's pricing table includes CRM integrations on the Growth and Enterprise plans and not on Free or Launch. Clay's pricing FAQ lists Growth from $495 a month and Launch from $185 a month. If the build writes to HubSpot custom objects, the HubSpot portal also needs to be on Enterprise, because Clay's documentation says custom object permissions can only be granted there.
How do I stop Clay from creating duplicate companies in HubSpot?
Run a Look up object step on company domain, or on a custom unique-value property, before every create, and branch the row: update the record if one is found, create one only if none is. HubSpot states that companies created through its API are not deduplicated by domain, and Clay's update action needs the HubSpot record ID, so the lookup is what keeps one company as one record. Keep the domain setting the same in lookups and writes.
What does a HubSpot partner tier tell me about a Clay agency?
It tells you how much HubSpot revenue the firm sources, assists or manages, and for Elite partners that average gross revenue retention is at least 80% over 12 months. It does not test Clay or integration skill. The Custom Integration and Data Migration accreditations on a HubSpot listing are closer evidence, and a walkthrough of the Write-Back Contract against your own records is the direct test.
How much does a GTM engineering agency with Clay and HubSpot experience cost?
On their Clay listings, FullFunnel, Frontal AI, Enablement and Sculpted show $5k+ a month, Skydog Ops shows $10k+ a month, and RevPartners, LeanScale, Peakora, Levver and Understory show "any budget"; minimums run from one to six months. Add Clay's Growth plan: a three-month engagement at $5k a month plus Growth at $495 a month comes to at least $16,485 before data-provider costs and HubSpot seats.
How to Read the Rubric
Each row uses the firm's Clay Solutions Partner Directory listing, its HubSpot Solutions Directory listing where one is cited, and the firm's own website. "HubSpot directory" in a cell means the tier shown on HubSpot's listing for that firm; a quoted phrase means the firm's own claim. "None shown" means the HubSpot listing displays no accreditation; "No HubSpot listing cited" means the row relies on the firm's own words. Rows are grouped by the strength of HubSpot evidence and listed alphabetically within each group, with no score or rank. Review counts and customer results are vendor-reported and not audited.
Sources
- Clay, Solutions Partner Directory, and partner listings for Aptitude 8, FullFunnel, LeanScale, Peakora, RevPartners, Understory, Enablement, Frontal AI, Levver, Sculpted and Skydog Ops: tiers, expertise tags, price bands, minimums and descriptions.
- HubSpot, Solutions Directory listings for Aptitude 8, FullFunnel, LeanScale, Peakora, RevPartners and Understory: tiers, accreditations, services, review counts and budgets.
- HubSpot, How Tiers Work: tier points per $100 MRR and the Elite retention requirement.
- HubSpot Knowledge Base, Deduplication of records: email and domain deduplication and the API exception.
- HubSpot Knowledge Base, Use lifecycle stages: forward-only default updates.
- Clay University, HubSpot integration: create, look up, update, association, owner, list and sequence actions, defaults and OAuth scopes.
- Clay, Pricing: plan feature table and pricing FAQ.
- RevPartners, Clay agency page: the Clay-to-HubSpot integration offer and dual-tier claim.
- Walker Sands, Walker Sands Acquires RevPartners to Expand RevOps and GTM Engineering Capabilities, June 10, 2026.
- Frontal, home page: the stack and handover statement and the Elite Studio count on the home page.
- Levver, home page: the HubSpot partner statement.
- Sculpted, home page: the CRM Clean-up Sprint and its pre-work.
- Understory, home page and 10 Best GTM Engineering Agencies for B2B SaaS: positioning and its own roundup.
- Percepture, B2B Intent Data services and How to Use Intent Data to Identify Sales Qualified Leads. Percepture is the company where the author is President.
- Lead Seeker, How it works, Lead Compass and Pricing: the signal-to-dossier flow, HubSpot sync, Pilot and free-leads offer.
About the Author
Bob Generale is President of Percepture. He works across SEO, AI search, digital PR, sales intelligence and AI-powered revenue systems, with a focus on connecting visibility, buyer intent and sales action.
Next Steps
Run the Two-Directory Check on your shortlist, then send each firm the Write-Back Contract and ten of your own company records and ask for a written answer on every line. For more on the signal and record stages, browse the lead intelligence insights library.