Customer Success: definition, role, and best practices

Solène Augait
Glossary
- 8 min reading
Published on
January 7, 2026

Customer service responds to problems. Customer Success anticipates them. That nuance changes everything.

In a world where retaining customers costs less than acquiring new ones, customer success has become a strategic pillar for businesses, particularly in SaaS. In this guide, discover what customer success is, how it differs from support, and how to implement it.

Customer Success: definition

Customer Success is a proactive approach that aims to ensure that customers achieve their goals through your product or service.

The central idea: if your customers succeed, you succeed.

The Customer Success Manager (CSM) does more than just respond when the customer calls. They anticipate, support, and actively work toward the customer's success.

Customer Success vs. Customer Service: The Differences

AppearanceCustomer ServiceCustomer Success
ApproachResponsiveProactive
TriggerThe customer contactsThe CSM initiates
FocusSolve problemsAchieve the objectives
Key metricSatisfaction, resolution timeRetention, expansion, adoption
HorizonShort term (the ticket)Long term (the relationship)

The two are complementary. Support deals with emergencies, while Customer Success builds longevity.

Why Customer Success has become essential

The SaaS model changed everything

With monthly subscriptions, customers can leave at any time. The initial sale is just the beginning: true value is built over time.

The cost of churn

Losing a customer means losing all the future revenue they would have generated. Customer Success is ananti-churn investment.

Expansion as a driver of growth

The best customers don't just stay: they buy more. Customer Success identifies and cultivates these opportunities.

The power of word of mouth

A successful customer spreads the word. They become ambassadors, references, and sources of qualified leads.

The roles of Customer Success

1. Onboarding

Support new customers in their first steps so that they quickly achieve their first success ("time to value").

2. Adoption

Ensure that the customer actually uses the product, discovers the relevant features, and gets the most value out of it.

3. Retention

Identify signs of disengagement and intervene before the customer leaves.

4. Expansion

Identify opportunities for upselling and cross-selling when the customer is ready and it makes sense for them.

5. Advocacy

Turning satisfied customers into ambassadors: testimonials, references, case studies.

Customer Success KPIs

Retention metrics

  • Retention rate (GRR): % of revenue retained
  • Net Revenue Retention (NRR): retained revenue + expansion
  • Churn rate: % of customers/revenue lost

Engagement metrics

  • Adoption: % of features used
  • Health Score: composite score of the customer's "health"
  • Logins / Usage: frequency of use

Growth metrics

  • Revenue expansion: additional revenue from existing customers
  • NPS: Net Promoter Score
  • CSAT: overall satisfaction

The Health Score: predicting success

The Health Score is a composite indicator that assesses the "health" of a customer account. It aggregates several signals:

  • Product use
  • Engagement with the team (responding to emails, participating in training sessions)
  • Business results achieved
  • Satisfaction expressed
  • Up-to-date payments

A declining Health Score = a warning sign for proactive intervention.

Customer Success and Customer Service: Collaboration

Both teams must work hand in hand:

Information sharing

Support sees issues in real time. Customer Success must be alerted to critical or recurring tickets.

Climbing toward the CSM

Some tickets reveal underlying issues that require Customer Success support, not just a one-off resolution.

Feedback loop

Support insights (frequently asked questions, recurring frustrations) fuel the Customer Success strategy.

Unified customer view

The CSM and support agents must have access to the same customer history for a consistent experience.

Set up a Customer Success team

1. Define your goals

Reduce churn? Increase expansion? Improve onboarding? Start with the problem to be solved.

2. Segment your customer base

Not all customers require the same level of support:

  • High-touch: Dedicated CSM, regular interactions (large accounts)
  • Mid-touch: Shared CSM, regular points (average accounts)
  • Tech-touch: automation, self-service (small accounts)

3. Recruit the right candidates

The CSM is neither a salesperson nor a support person. It combines:

  • Interpersonal skills
  • Product knowledge
  • Business vision
  • Analytical skills

4. Get equipped

Customer Success tools (Gainsight, ChurnZero, Vitally), CRM, product analytics... Data is the fuel that drives CS.

5. Measure and iterate

Define your KPIs, track them, and adjust your approach based on the results.

Automation at the service of Customer Success

Customer Success cannot do everything manually, especially with a large customer base:

Automated onboarding

Email sequences, in-app guides, activation checklists...

Automatic alerts

Notification when a Health Score drops, when usage falls, when a renewal is approaching...

Segmented communications

Emails customized according to segment, life cycle stage, behavior, etc.

Klark fits into this approach by automating part of the customer support process: instant answers to questions, detection of signs of dissatisfaction, and high-quality support that boosts retention.

Mistakes to avoid

Mistake #1: Confusing CS and Account Management

The CSM is not a salesperson. Their primary goal is customer success, not sales. Trust comes before revenue.

Mistake #2: Being reactive instead of proactive

If the CSM only intervenes when the customer calls, it's no longer Customer Success, it's support.

Mistake #3: Ignoring small accounts

Even without a dedicated CSM, small accounts deserve a Customer Success experience through automation.

Mistake #4: Not collaborating with support

The support team has valuable insights. Not taking advantage of them is a missed opportunity.

Mistake #5: Focusing solely on churn

Customer Success is also about expansion and advocacy. Don't limit yourself to preventing departures.

Frequently Asked Questions

When should you create a CS team?

As soon as churn becomes a significant issue or you have enough customers to justify the investment. In SaaS, this is often from 50-100 customers.

Can CSM and support be the same person?

In a small team, yes, but the tasks are different. As the team grows, specialization becomes necessary.

How can you measure the ROI of Customer Success?

Compare churn and NRR before and after, the cost of the CS team vs. the value of retained customers.

Does Customer Success exist outside of SaaS?

Yes, the concept applies wherever retention matters: services, subscription-based e-commerce, B2B, etc.

Conclusion

Customer Success is not a luxury, it is a strategic investment. In a world where acquisition is expensive and customers can easily leave, proactively supporting them toward success is the key to sustainable growth.

The keys to Customer Success:

  • Take a proactive approach, not a reactive one
  • Focus on the client's goals, not just their problems.
  • Segment to tailor the level of support
  • Work closely with support
  • Automate to scale
  • Measure retention, expansion, and advocacy

Your customer service directly contributes to your customers' success. Discover how Klark can help you achieve this.

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