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Which KPIs should you track to evaluate your mailbot's performance?

Updated on 29/04/2025
Essential kpis to measure a mailbot's performance

Today, mailbots have become valuable allies for support teams. Available 24/7, they quickly respond to the most common email requests while relieving pressure on traditional support channels. But like any tool, it's essential to measure their effectiveness using the right metrics and to continuously optimize them. What results do they actually deliver? What are their limitations? Here are 10 essential KPIs to assess your mailbot’s performance, identify areas for improvement, and enhance the customer experience over the long term.

What is a mailbot?

A mailbot is an artificial intelligence (AI) tool designed to automate the processing of incoming emails and simplify customer request management. Far beyond traditional auto-replies, it can deeply analyze the content of messages, extract key information, and trigger appropriate actions often without any human intervention.

 

Thanks to advanced technologies like natural language processing (NLP) and machine learning, the mailbot accurately understands the messages it receives, detects customer intent and emotions, and extracts useful data such as contact details, order references, or attachments. It can also categorize emails by topic or urgency level, respond automatically when a simple action is needed (such as sending a file or resetting a password), or forward more complex requests to the appropriate team members. For multilingual exchanges, it can even handle message translation autonomously.

 

The mailbot can easily integrate with existing tools in the company, such as a CRM or a ticketing platform. The result: smoother workflows and more time for teams to focus on what really matters. This aligns with the concept of the “augmented advisor”: humans remain at the heart of customer relationships, supported by technology. The mailbot handles low-value tasks, allowing advisors to dedicate their time to situations that require listening, empathy, and expertise. The mailbot doesn’t replace human agents, it supports them, helps them work more efficiently, and enables them to deliver even greater value in every interaction.

 

Learn more: The 5 best use cases for mailbots in business

The 10 KPIs to track for effectively managing your mailbot

1. First Contact Resolution (FCR)

FCR is a key metric for assessing your mailbot’s effectiveness. It indicates how well the mailbot can provide a correct and complete answer to a request on the first interaction. A high resolution rate means the user received a satisfactory response without needing to rephrase their query or be transferred to a human agent. This is a strong sign that your automation system is well-designed, with accurate replies and well-structured workflows.

Recommended benchmark: The average FCR rate is around 70%.

 

2. Deflection rate


The deflection rate measures the percentage of customer requests that would normally require human agent involvement but are resolved automatically by the mailbot. The higher this rate, the more your mailbot is reducing your team’s workload and cutting support costs. It’s a direct indicator of return on investment and the maturity of your automation strategy.

Recommended benchmark: between 30% and 50%, depending on the complexity of customer requests.

 

3. Escalation rate to a human agent


This KPI evaluates your mailbot’s ability to handle customer requests independently. A high escalation rate suggests that many queries are misunderstood or poorly managed, requiring human intervention. It can point to issues such as incomplete data, poorly configured workflows, or insufficient training of the natural language processing engine. Conversely, a low rate indicates that the mailbot is effectively filtering and resolving requests.

Recommended benchmark: below 40%.

 

4. Customer Satisfaction Score (CSAT)


CSAT reflects how users perceive the interaction with the mailbot. It’s usually measured immediately after the exchange, via a quick question like “Are you satisfied with this interaction?” This score highlights the user's experience in terms of clarity, speed, and overall satisfaction. A strong CSAT indicates that the conversation was smooth, the response was helpful, and the resolution was effective. It's a key metric for tracking customer acceptance of your mailbot.

Recommended benchmark: a score above 70%.

 

5. Open and Click-Through Rate for enriched responses

When your mailbot includes helpful links (FAQs, articles, forms), the open and click-through rates help measure how relevant and effective those resources are. If users open the email but don’t click, it may signal a lack of clarity or interest in the suggested content. A good click rate indicates that the mailbot drives engagement and successfully guides users toward useful information.

Recommended benchmarks: open rate > 50%, click-through rate > 10%.

 

6. Average response time


Speed is one of the major advantages of a mailbot. This KPI tracks the time between receiving a request and sending a response. The shorter the delay, the smoother the user experience. A long response time can frustrate users who expect instant assistance. This KPI is also key to assessing your company's professionalism and responsiveness.

Recommended benchmark: under 1 minute.

 

7. Error or misunderstanding rate

 
This KPI reflects the mailbot’s ability to accurately understand user intent. When a mailbot gives an irrelevant or incorrect response, it can lead to frustration, confusion, or conversation drop-off. A high error rate indicates a need to improve natural language processing (NLP) or enhance the response database. This metric is crucial for refining algorithms and conversation scenarios.

Recommended benchmark: below 10%.

 

8. User engagement rate


This KPI tracks how many interactions are needed between the user and the mailbot to reach a resolution. A good engagement rate is balanced, too low may indicate a lack of usefulness or interest, while too high may signal a confusing journey or unclear responses. It’s an excellent indicator of conversation flow and overall user experience.

Recommended benchmark: between 2 and 5 exchanges per conversation.

 

9. Abandon rate


The abandonment rate measures how many users leave the conversation before receiving a satisfactory response. This can be due to lengthy dialogues, misunderstood questions, or a lack of clarity. A high abandonment rate may indicate that the mailbot is not intuitive enough or is causing frustration. It's a key metric to monitor in order to improve the user experience.

Recommended benchmark: below 15%.

 

10. Total volume of requests handled


This KPI measures the overall activity of your mailbot. It provides a global view of the workload the mailbot manages daily. Tracking this volume over time helps you anticipate activity spikes, plan resource adjustments, and fine-tune scenarios based on the most frequent types of requests. It’s a valuable indicator for assessing the mailbot’s real impact on your support operations.

Recommended benchmark: to be defined based on the size of your customer base and the service’s availability hours.

Tracking the right KPIs is more than just a reporting exercise, it’s a powerful lever for strategically evolving your customer service. By monitoring these key indicators, you gain a clear understanding of your mailbot’s real impact, relevance, and effectiveness in your users’ daily experience. This insight allows you to fine-tune workflows, strengthen weak points, and most importantly, deliver an experience that meets expectations: fast, seamless, and personalized. In the long run, a well-optimized mailbot becomes more than just a support tool, it becomes a true driver of customer satisfaction.

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