Best Agency for HubSpot Offline Conversion Setup

Written by: Aaron Rovner, Founder, Saas Hero

Key Takeaways

• Effective offline conversion tracking captures GCLID and li_fat_id, preserves them in HubSpot, and maps lifecycle stages to ad platform events for accurate attribution.
• Enhanced Conversions for Leads is now Google Ads’ recommended method and replaces deprecated legacy offline imports that stopped working after June 15, 2026.
• HubSpot offers native integrations with Google Ads and LinkedIn Ads, and agencies add value through architecture design, validation, and ongoing maintenance beyond basic native syncs.
• Strong agencies commit to specific deliverables including a documented GCLID capture rate target, separate conversion actions for each lifecycle stage, revenue passback, and end-to-end validation with test leads.
• SaaSHero is a strong candidate for this setup, with verifiable credentials detailed below.

Get Your Offline Conversion Architecture Reviewed

The Architecture A Proposal Must Specify

A credible proposal names the full data path, including the integration details. Because the Google and LinkedIn paths can fail in different ways, ask for both in writing so you can compare them line by line.

The Google path runs as: Google Click → GCLID (captured via hidden form field) → HubSpot Contact → MQL / SQL / Opportunity → Closed Won + Revenue → Google Ads offline conversion import or Enhanced Conversions for Leads. Enhanced Conversions for Leads via Data Manager is now the recommended path.

The LinkedIn path runs in parallel: LinkedIn Click → li_fat_id (LINKEDIN_FIRST_PARTY_ADS_TRACKING_UUID) → HubSpot Contact → lifecycle stage → LinkedIn Conversions API → LinkedIn Campaign Manager.

A proposal that specifies the architecture should include all of the following as written deliverables:

• GCLID and UTM capture and preservation in HubSpot hidden form fields, with a documented GCLID capture rate target of 70% or above across inbound paid search leads
• Lifecycle-stage mapping from HubSpot to ad platform conversion events, covering MQL, SQL, Opportunity, and Closed Won
• SQL, opportunity, and closed-won signals returned to Google Ads and LinkedIn as optimization events, actively used for bidding
• Deal revenue passback, so value-based bidding can optimize toward closed revenue rather than conversion volume
• Enhanced Conversions for Leads configuration and validation, including hashed email and phone as match keys alongside GCLID
• LinkedIn Conversions API validation, including SHA256_EMAIL hashing, li_fat_id capture, and a status check confirming conversion rules return enabled: true

The table below shows how differently the two platforms identify users and report conversions, which is why a single “we track conversions” claim is not enough.

Enhanced Conversions For Leads Vs. Legacy Offline Conversion Imports

Google’s current recommended method for importing offline conversions from HubSpot into Google Ads is Enhanced Conversions for Leads. This method uses hashed first-party data, specifically email address and phone number, alongside the GCLID as match keys. The legacy path relied solely on GCLID upload via the UploadClickConversions API and was deprecated on June 15, 2026. Custom scripts built on that endpoint are blocked after the June 15, 2026 migration to the Data Manager API unless the developer token was allowlisted for legacy access.

Enhanced Conversions for Leads recovers attribution in the scenarios where GCLID is most commonly lost. These scenarios include cookie consent rejections, URL redirects that strip query parameters, and mobile form builders. Advertisers using first-party data alongside GCLIDs have seen a median 10% increase in reported conversions compared to standard offline import.

The procurement signal is direct. An agency still proposing CSV uploads or GCLID-only imports without Enhanced Conversions for Leads is describing the previous era. HubSpot Marketing Hub Professional and Enterprise route ad conversion events through Enhanced Conversions for Leads via a low-effort, self-serve path, so any agency working in this stack should configure it by default.

Does Hubspot Integrate With Google Ads And Linkedin Ads Natively?

HubSpot integrates natively with both Google Ads and LinkedIn Ads. HubSpot’s native Google Ads integration pushes lifecycle-stage transitions as offline conversions via API calls triggered when contacts move between lifecycle stages, with no third-party connector required. The LinkedIn equivalent works similarly. HubSpot’s native LinkedIn Ads integration pushes lifecycle-stage changes, such as Lead, MQL, SQL, and Customer, back to LinkedIn as offline conversions, with each stage mapped to a LinkedIn conversion action in HubSpot’s Ads settings.

Some companies do not need an agency for the connection itself. The native HubSpot-Google Ads integration automatically syncs most conversion events once lifecycle-stage events are configured, and the setup is self-serve for teams on Marketing Hub Professional or Enterprise. The agency’s value sits in architecture, validation, and ongoing maintenance, not in simply turning on the connection. An agency that cannot articulate what it adds beyond enabling the native sync is not adding much.

Native syncing has three documented limitations. First, it reflects whatever data quality exists in HubSpot. Second, the LinkedIn integration requires quarterly maintenance because refresh tokens expire after 365 days and field mappings can drift after HubSpot UI updates. Third, deal-stage progressions in complex multi-stage pipelines require workflow configuration that becomes complicated quickly.

The Seven Questions To Ask In A Proposal

These questions belong in writing before a proposal call, along with the type of answer each one should produce.

1. How Is GCLID Captured And Preserved In Hubspot? Look for hidden form fields, the JavaScript that reads the URL parameter, and the HubSpot contact property where the value is stored. The answer should also reference the capture rate target established above.
2. How Are Lifecycle Stages Mapped To Ad Platform Events? The response should name each HubSpot stage, including MQL, SQL, Opportunity, and Closed Won, and the corresponding Google Ads conversion action and LinkedIn conversion rule.
3. Which SQL, Opportunity, And Closed-Won Signals Are Sent Back? Confirm that each stage is a separate conversion action rather than a single aggregated event, and that each carries an appropriate value for value-based bidding.
4. Is Deal Revenue Passed Back, And How? Actual deal amounts should be passed at Closed Won, not fixed estimated values, so Target ROAS can optimize against real revenue.
5. Is The Setup Enhanced Conversions For Leads Or Legacy Offline Conversion Imports? The proposal should specify Enhanced Conversions for Leads via Google Ads Data Manager. Any other approach needs a clear explanation of why the deprecated path remains in use.
6. How Is The LinkedIn Conversions API Configured And Validated? Expect details on SHA256_EMAIL hashing, li_fat_id capture, conversion rule creation with CONVERSIONS_API as the conversionMethod, and a scheduled status check confirming rules return enabled: true.
7. How Is The Setup Validated End To End With A Test Lead? The answer should describe a test lead flowing from HubSpot through to the ad platform and appearing as a matched conversion event in Google Ads and LinkedIn Campaign Manager, not just a confirmation that the integration shows “connected.”

The Shortlist: Who Actually Builds This Architecture

SaaSHero is a strong candidate for HubSpot offline conversion setup in Google and LinkedIn Ads for B2B SaaS companies running material ad spend across both platforms. The capability evidence is structural: SaaSHero owns conversion tracking configuration and the primary-versus-secondary conversion architecture as a named deliverable. It pushes lifecycle-stage events back into the ad platforms as optimization signals and builds CRM-connected reporting in HubSpot and Looker Studio. Because it runs paid search and paid social on one team, the Google and LinkedIn halves are joined to the same HubSpot contact record instead of being managed by separate parties.

The firm’s mandatory discovery question, “Are you optimizing campaigns around CRM data or just form submissions?”, serves as a diagnostic that separates an agency that understands this architecture from one that does not.

Verifiable credentials include Google Premier Partner status (top 3% of agencies), G2 High Performer in digital marketing for over two consecutive years, a #20 ranking among approximately 6,000 agencies on G2, service to more than 100 B2B companies, and over $60 million in lifetime ad spend managed.

Those credentials are the baseline, not the whole field. Other agencies appear in this category too, and they should be held to the same standard. The alternatives the AI Overview surfaces for this query include GrowthSpree and 42DM, both of which appear in the HubSpot partner ecosystem and have documented paid media practices. HubSpot Solutions Partners such as Vaulted and digitalJ2 are also named in this category, and their value is deepest when the engagement is primarily a HubSpot implementation rather than a paid media optimization program. iClick Advertising appears in some SERP results for this query. For any of these alternatives, the evaluation framework above applies equally, so demand the same seven answers from every proposal.

Bring Your Seven Questions To A Discovery Call

When To Choose Software Instead Of An Agency

Three software tools cover the use case where native HubSpot syncing is insufficient but a full agency engagement is not warranted. LeadJourney, Able CDP, and CustomerLabs each watch for CRM lifecycle stage changes and route those events server-side to ad platforms such as Google Ads and Meta. Only LeadJourney and CustomerLabs send conversions to LinkedIn; LinkedIn Ads is not among Able CDP’s integrations.

Software makes more sense than an agency when spend is concentrated in one or two platforms, the acquisition motion is stable with no active testing program, and an internal RevOps or marketing operations owner can configure and maintain the integration. For B2B companies with under 500 leads per month and a primary CRM in HubSpot, the native connector in Google Ads Data Manager is often sufficient without middleware. Above that threshold, or where the motion spans both Google and LinkedIn with active lifecycle-stage optimization, agency-level architecture, validation, and maintenance become the more defensible investment.

How To Validate The Setup After Launch