10 key marketplace metrics to measure success
Ten marketplace metrics explained: MAU, engagement, bounce rate, supply-demand ratio, repeat purchases, GMV, CPA, CLV, NPS and the Sean Ellis test.
The ten metrics covered here are monthly active users, engagement time, bounce rate, vendor-to-customer ratio, repeat purchase rate, GMV, CPA, CLV, NPS and the Sean Ellis test. Track take rate and liquidity as related measures: assess liquidity with measures such as match rate, fill rate or time to match, not bounce rate or vendor-to-customer ratio alone.
At Code23 we’ve built 50+ marketplaces over 15+ years. Tracking these measures early makes problems easier to spot. Total sign-ups and page views need context; combine them with transaction, retention and unit-economics measures to understand whether the marketplace is becoming more useful, for both the vendors selling on it and the customers buying from it.
Below are the ten metrics worth tracking, what each one actually means, and what to do when the numbers don’t add up.
There are three key marketplace KPIs worth mentioning and these revolve around monthly active users (MAU), the amount of time spent engaging on your site and the bounce rate. Define an active user by a meaningful action for your marketplace, such as searching, enquiring, listing or transacting; a visit alone may be too weak. In Google Analytics 4, bounce rate is the percentage of sessions that were not engaged sessions; if you use another analytics tool, document its definition before comparing results.
If MAU is flat, use acquisition and cohort-retention data to distinguish new-user growth from returning-user loss. Likewise, if the bounce rate is high you need to work out why visitors are not engaging and ultimately completing transactions.
Vendors may find active demand and completed transactions useful, but MAU and bounce rate need context rather than being treated as decisive on their own.
In addition to these three, there are other key marketplace metrics pertinent to online marketplace platforms that will enable you to better judge what you can change.
- Make sure you have a good vendor to customer ratio
This involves working out how many customers can be served by one vendor. Choose supply-demand measures that reflect capacity, transaction frequency and buyer demand; transaction value alone does not determine the required ratio. If demand per vendor is high, it’s even more important to make sure you focus on vendors in the early days.
- Aim for a high repeat purchase ratio
Repeat purchases can improve acquisition economics, but only when the contribution margin they generate exceeds fulfilment, support, retention and other variable costs. That’s why it’s so important that people have a good experience when using your site, you want them to come back!
"We worked with Code23 for a complete rebuild of our music related website. Excellent customer service and quality throughout and the build they have now completed is fantastic - exceeded all expectations across the board. Fantastic company with a dynamic and motivated team who are great to work with. Would highly recommend!"
- Consider your Gross Merchandise Volume (GMV)
Put simply, this is the total value of sales of your products or services in a given period of time. GMV measures the gross value transacted, not marketplace revenue or profitable growth. GMV multiplied by take rate (the percentage of GMV your marketplace keeps as commission) estimates gross platform revenue before refunds, incentives, payment costs, taxes and other adjustments.
- Work out your Cost per Acquisition (CPA)
This is the price it costs you to acquire a new customer. Track acquisition cost against the value of the customers it brings in, rather than minimising it without regard to quality. In an ideal world, customers will recommend new customers, but chances are you will have to spend something, be it on paid advertising or other marketing channels.
- Calculate your Customer Lifetime Value (CLV)
Customer lifetime value (CLV) estimates the contribution a customer generates over the time they stay with you, not simply their gross spend. When working this figure out, bear in mind how many times you expect them to purchase, the cost of the average transaction and how long you can retain them.
Estimate customer spend as average order value (AOV: GMV for a defined period divided by completed transactions in the same period) multiplied by expected lifetime orders per customer. Then apply your take rate and subtract payment, support, refund, incentive and other variable costs to estimate contribution CLV.
Compare your CPA with that contribution CLV: if acquisition cost is higher, take a good look at the customer journey on your site and at what stage people leave without completing a transaction. If it’s that not many people visit your site at all you will need to focus on customer acquisition.
If you have a high bounce rate, you might be attracting the wrong sort of people in the first place. If visitors engage but do not transact, investigate supply, pricing, trust, search, checkout, payment and technical problems before deciding that vendor supply is the cause.
Along with these values, it's worth looking at user satisfaction. NPS is one possible satisfaction or loyalty measure, alongside the Sean Ellis test.
9. The Net Promoter Score became well-known in 2003 when it featured in the Harvard Business Review. Respondents answer the question ‘How likely is it that you would recommend (your marketplace) to a friend or colleague?’ on a 0-10 scale, but NPS itself is the percentage of promoters minus the percentage of detractors, and ranges from -100 to +100. The answers are divided as follows:
- 0–6: Detractors – respondents classified as least likely to recommend the marketplace
- 7-8: Passives – these are not enthusiastic customers but they are satisfied
- 9-10 Promoters – loyal enthusiasts, though a high score doesn't guarantee they'll keep buying or refer others
Subtract the percentage of detractor customers from the percentage of promoter customers and you’ll have your NPS. Interpret the result against an appropriate benchmark and trend rather than treating universal thresholds as proof of performance. Repeat the survey consistently to track changes in NPS. Treat it as one loyalty signal alongside behaviour, retention and support data; it is not proof that overall customer satisfaction has improved.
10. The Sean Ellis test asks how disappointed active users would be if they could no longer use the product. It is commonly used as one product-market-fit signal. The question is ‘How would you feel if you could no longer use our marketplace?’.
The four possible answers are:
- Not applicable – I no longer use the product
- Not disappointed
- Somewhat disappointed
- Very disappointed
It is a useful tool, particularly alongside NPS, though it does not measure recommendation likelihood, which is what the NPS question addresses; instead, the share answering ‘Very disappointed’ is commonly treated as one product-market-fit signal, not proof that users are receiving value.
Make sure you consistently review these important metrics and keep improving your marketplace business, understand which area isn’t working and what you can do about it. And never forget to talk to your vendors and customers to ensure you are meeting their needs.
Frequently asked questions
What are the top 3 marketplace metrics to start with?
Start with measures tied to your marketplace’s current constraint. For many transactional marketplaces, that may include GMV, gross platform revenue derived from take rate, and a defined liquidity measure such as match rate, fill rate or time to match. Add acquisition, retention and contribution measures where they answer a decision you need to make.
What are the most important marketplace KPIs to track overall?
There isn’t one universal list, because it depends on your model, but the group that keeps coming up is GMV, take rate, liquidity, customer acquisition cost against lifetime value, repeat purchase rate, your vendor to customer ratio and satisfaction, measured through NPS or the Sean Ellis test. Select a small, defined set appropriate to your marketplace’s stage and model, document how each is calculated, and add measures as your operating model develops, rather than waiting until growth stalls to work out why.
What metrics matter most for a B2B marketplace?
Some B2B marketplaces have fewer, larger transactions or longer sales cycles. Where that applies, consider GMV per account, time to first transaction, response or fill rate, and repeat transactions alongside user counts. Repeat transactions can be one trust signal.
What’s a good take rate for a marketplace?
There’s no single healthy number. Take rate depends on how much value your marketplace adds beyond the introduction: payments, trust, search, logistics, and what your category can bear. A listing-only marketplace may justify a different take rate from one providing payments or dispute handling; test the rate against the value delivered and the category’s economics. If you’re not sure where yours should sit, that’s exactly the kind of question our free Marketplace Growth Review can help you judge.
Next step
These ten metrics only earn their place if you’re actually tracking them and checking them against each other: GMV against take rate, CPA against CLV, vendor numbers against customer numbers. Select a small, defined set appropriate to your marketplace’s stage and model, document how each is calculated, and add measures as your operating model develops.
The Marketplace Growth Review is a free 30-minute call that can help you work out what the trends may mean and what to investigate next; no individual set of metrics predicts growth. If you want it written down, the Marketplace Growth Plan reviews your buyer, seller and admin journeys alongside your metrics at a fixed price, credited against the build if you go ahead. We’ve built 50+ marketplaces over 15+ years.
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