Integrate your application into the HubSpot Marketplace
Software publishers, give your solution the visibility it deserves and make adoption easier for thousands of HubSpot users!
Why create a HubSpot connector?
+258,000 companies use HubSpot
Integrate your solution into one of the most popular CRMs on the market.
Enhanced and streamlined usage
Give your customers the ability to fully use your solution within HubSpot.
Data security
Ensure a reliable and secure integration for your users.

5 steps to co-build your application for HubSpot
1 – Diagnosis and exploration
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Object and data flow mapping (app ↔ HubSpot): sources, frequency, data volume, latency.
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API audit: endpoints, limits, authentication (OAuth, API keys), webhooks, error handling.
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Review of existing data flows (ETL/iPaaS, n8n/Make, scripts, middleware).
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Functional scoping: priority use cases (contact creation, deal sync, product events, invoicing, tickets, etc.).
2 – Functional specifications document
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Object modeling (HubSpot standard & custom objects) and field-to-field mapping.
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Business rules: deduplication, normalization, error handling & retries.
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Security & compliance: GDPR, permissions, retention policies, logging and traceability.
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Success KPIs: data freshness, success rate, latency, coverage.
3 – Mi4 develops or supports you in building your connector
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Connector development by Mi4 teams (private app or marketplace app), including OAuth management and webhooks.
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Test environments and monitoring.
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Technical documentation and operations guide.
OR
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Coaching for your developers (code reviews, architecture, security).
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HubSpot best practices.
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Shared Q&A sessions.
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HubSpot compliance validation.
4 – Pilot phase & adjustments
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Controlled pilot phase on a limited scope (sample of users/customers).
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Observability: logs, metrics, error and latency dashboards.
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Fast iteration loops: fixes, mapping optimizations, quota adjustments.
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Team training
5 – Publication on the HubSpot Marketplace
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Marketplace compliance: branding, scopes, privacy, HubSpot reviews and criteria.
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Packaging & listing: description, screenshots, tutorials, release notes.
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Support & maintenance: SLAs, roadmap, monitoring HubSpot API changes.
Do you have a HubSpot connector project?
Let’s talk!
Spotlight on the “Connect” app for Ellisphere
Ellisphere wanted to offer its customers who use the HubSpot CRM a B2B enrichment application that is easy to install, reliable, and GDPR-compliant.
We supported them in developing the
"Connect" app for HubSpot.
Mi4 was engaged to design and develop the application.
Objective: to keep company records complete and up to date (identifiers, industry, executives, headcount, etc.) in order to better segment and prioritize sales efforts.
🔎 Note: The integration and pilot phase were carried out specifically for the Picoty Group, which was also supported by Mi4 for its HubSpot onboarding.
Reliable enrichment at your fingertips
Native HubSpot app with logs and monitoring
- Enrichment, cleansing, and updating of company records directly within HubSpot
- Bidirectional connection
- Flexible mapping (standard and custom objects), deduplication, error handling and retries
- Customizable configuration panel within HubSpot
- Pilot phase with the Picoty Group
“Since Mi4 deployed the ‘Connect’ app with Ellisphere, our quote preparation has reached a whole new level: **3 days saved per salesperson** in the quoting process. We can finally focus on selling, not on data entry.”
Vous avez un projet d’application sur-mesure ?
Do you have questions about HubSpot connectors?
We have the answers.
How long does it take to build a HubSpot connector?
It really depends on the scope and level of customization. From a focused prototype to a full connector ready for the Marketplace, timelines typically range from a few weeks to several months. The main factors include:
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Objects and business rules (simple mapping vs. complex logic)
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Data volumes and sync frequency (real-time, batch, incremental)
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Quality and limits of the third-party API (documentation, quotas, available webhooks)
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Security and GDPR requirements, as well as internal validation
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Target usage: private use vs. Marketplace publication (reviews and packaging)
We always start with a quick diagnostic to estimate a realistic timeline and define key milestones (pilot, go-live).
Is it necessary to publish the connector on the HubSpot Marketplace?
Not necessarily.
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Private: ideal if you’re connecting an internal system (faster, more flexible).
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Marketplace: useful if you sell your app to other customers (listing, support, compliance). Mi4 handles both scenarios.
Which data and objects can be synchronized?
All HubSpot standard objects (Contacts, Companies, Deals, Tickets, Products) as well as custom objects.
Common features include: data enrichment, deduplication, event webhooks, incremental synchronization, and error handling with retries.
What about security, GDPR, and API limits?
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OAuth authentication, encryption in transit, logging/monitoring, and access controls.
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GDPR: data minimization, consent management, data subject rights (deletion, rectification), and audit trails.
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API quotas: resilient design (batching, backoff, queues) to handle high volumes.
Who maintains the connector, and what happens if the API changes?
Mi4 offers a maintenance SLA covering fixes, enhancements, and monitoring of HubSpot API versions as well as the application side.
You get documented code, a runbook, alerts, and error dashboards.
Optionally, an evolution package is available to add new use cases or objects over time.
"Nous avons confié à Mi4 la mise en place de notre nouveau CRM HubSpot, incluant une customisation avancée et le développement d’API sur mesure pour connecter nos différents outils métiers. Leur équipe a su comprendre nos besoins, proposer des solutions pertinentes et les mettre en œuvre avec une grande réactivité. Une collaboration fluide et efficace que nous recommandons sans réserve."
"Au cours des six derniers mois, notre équipe marketing a beaucoup bénéficié de la collaboration avec Mi4. La valeur qu'Irina apporte à la fois en tant qu'experte en la matière et en tant que gestionnaire de projet ne peut être ignorée. Elle nous a beaucoup aidés à amener les efforts de notre équipe au bon niveau - vivement recommandé !"
"We worked with Mi4 to set up HubSpot for our business. Their understanding of our needs was great and overall the process was smooth. The training was adequate, and their communication was on point, with great insights and ideas. A great experience overall."
“On a recours aux services de Mi4 pour utiliser au mieux les fonctionnalités essentielles de HubSpot permettant : d'améliorer notre performance commerciale en interne, d'améliorer l'acquisition de leads et d'améliorer notre communication externe. L'équipe Mi4 nous a apporté une aide précieuse autant par son implication, son professionnalisme et sa passion de la réussite.”
“Mi4 nous accompagne sur de multiples sujets ainsi que sur la mise en place de HubSpot pour nos équipes Sales. Les équipes de Mi4 sont extrêmement performantes, le tout parfois dans des délais très contraints. La mise en place de HubSpot est une réussite, l'adhésion de nos équipes commerciales (+50 personnes) acquise, et cela grâce à Mi4 !"
“L'équipe MI4 a su créer et mettre en place notre activité de prospection digitale et d'Inbound marketing. Une équipe à l'écoute, qui a su proposer des contenus professionnels pour le blog malgré la complexité de notre activité, et qui a su également transférer leurs expertises à travers différentes formations.”
“We had a big project to optimize our company's processes using HubSpot, including developing automation on the support ticket side and training the sales to the new functionalities they could find in HubSpot (we migrated from Dynamics 365). It is a real pleasure to work with the team and they always find creative ways to answer our needs. Highly recommended!”
Your HubSpot Certified Diamond Integrator
In addition to being ranked among the top 15 French agencies, Mi4 holds multiple HubSpot accreditations.
Custom Integration
Authorization to extend your CRM through custom integrations and customizations
Platform Enablement
Expertise in improving adoption rates through tailored training and change management
Certified Trainer
Certified trainer in Inbound Marketing and HubSpot expertise, supported by the HubSpot Academy