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Faiss vs Microsoft Azure Cosmos DB comparison

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Comparison Buyer's Guide

Executive SummaryUpdated on Jan 25, 2026

Review summaries and opinions

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Categories and Ranking

Faiss
Ranking in Vector Databases
15th
Average Rating
8.0
Reviews Sentiment
3.3
Number of Reviews
3
Ranking in other categories
Open Source Databases (12th)
Microsoft Azure Cosmos DB
Ranking in Vector Databases
1st
Average Rating
8.2
Reviews Sentiment
6.9
Number of Reviews
114
Ranking in other categories
Database as a Service (DBaaS) (3rd), NoSQL Databases (1st), Managed NoSQL Databases (1st)
 

Mindshare comparison

As of October 2026, in the Vector Databases category, the mindshare of Faiss is 4.2%, down from 5.4% compared to the previous year. The mindshare of Microsoft Azure Cosmos DB is 5.6%, up from 5.0% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Vector Databases Mindshare Distribution
ProductMindshare (%)
Microsoft Azure Cosmos DB5.6%
Faiss4.2%
Other90.2%
Vector Databases
 

Featured Reviews

Kalindu Sekarage - PeerSpot reviewer
Senior Software Engineer
Integration improves accuracy and supports token-level embedding
The best features FAISS offers for my team include seamless integration with Colbert and the ability to use FAISS via the Ragatouille framework, which is tailor-made for using the Colbert model. Feature-wise, FAISS allows for more accurate result retrieval, and retrieval speed is also good when comparing the index size. Regarding features, I also emphasize that the usability of FAISS is very seamless, particularly its integration with Colbert and Ragatouille. FAISS has positively impacted my organization by helping us increase the accuracy of retrieval documents; when we store documents in token-level embedding, the accuracy will be high. Additionally, we do not need any external server to host FAISS, allowing us to integrate it with our backend framework, making it a very flexible framework.
Michael Hasenfang - PeerSpot reviewer
Director, Platform Engineering - Infrastructure Systems and Automation at a computer software company with 1,001-5,000 employees
Collecting compliance data has become more efficient while managing unstructured inputs for reporting
The features that I find most valuable within Microsoft Azure Cosmos DB are probably the cost, as the cost optimization is good. The storage and queryability are good for what we're doing; it's a lot of unstructured data, so having a platform to put that in and then be able to harvest that data out for the reporting we do is essential. In terms of cost saving, it was probably easily 30 to 40% cheaper than doing a standard SQL, which is what we saw just on piloting and getting in there. We were initially thinking 20 to 25%, but we were probably more at the 35 to 40%. We are using Microsoft Azure Cosmos DB's hybrid search today. The value that it has added to my AI or search workloads is that I think it's optimized that process and made it easier. We have a lot of unstructured data coming from different dissimilar systems and different data sources, so correlating those things together and making sense of it has been very beneficial. Microsoft Azure Cosmos DB has had pretty good performance with searching through large amounts of data; it's been fast, and we haven't seen a lot of performance degradation while building larger queries and bringing in a large set of data. The dynamic auto-scale or serverless model from Microsoft Azure Cosmos DB has helped reduce costs and operational effort; however, it's hard to quantify how that plays out since you're using a shared service. It shifts my focus away from building, managing, and upgrading to adding value.

Quotes from Members

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Pros

"I used Faiss as a basic database."
"The product has better performance and stability compared to one of its competitors."
"The solution is scalable, and we intend to increase our usage."
"In Microsoft Azure Cosmos DB, one valuable feature is its ability to store data in multiple regions. If one region fails, it automatically switches to a healthy region, ensuring minimal latency and disaster recovery without impacting data latency in applications."
"Microsoft Azure Cosmos DB's dynamic auto-scale or serverless model helps reduce costs or operational efforts, though I don't have extensive knowledge about this feature."
"Microsoft Azure Cosmos DB's most valuable feature is latency."
"Microsoft Azure Cosmos DB has reduced our total cost of ownership by about half, allowing us to sell our product for about half of what we were selling it before, and Microsoft Azure Cosmos DB is probably 70% of the reason why that's true."
"The dynamic autoscale or serverless model of Microsoft Azure Cosmos DB has indeed helped reduce our costs and operational effort by allowing us to scale horizontally in a straightforward manner according to our needs."
"Cosmos is preferred because of its speed, robustness, and utilization. We have all the merchandising information in Cosmos DB, which provides concrete and optimized data when searching for new products on the site. It is faster than other relational databases."
"Our customer is very satisfied with it."
 

Cons

"One of the drawbacks of Faiss is that it works only in-memory. If it could provide separate persistent storage without relying on in-memory, it would reduce the overhead."
"It would be beneficial if I could set a parameter and see different query mechanisms being run."
"It could be more accessible for handling larger data sets."
"There's a little bit of a learning curve because I was new to Azure. But once you learn the tool, it's pretty straightforward."
"One area for improvement is the ease of writing SQL queries and stored procedures in Microsoft Azure Cosmos DB. Writing an SQL query and a stored procedure on top of that is a little challenging."
"I have been a devoted Microsoft fan, but Redis DB's memory caching capabilities are really making progress. Even if Cosmos DB is continuously improving and is quite advanced in the field of internal memory optimization, I would still recommend Redis DB to a customer."
"The one thing that I have been working on with Microsoft with regard to this is the ability to easily split partitions and have it do high-performance cross-partition queries. That is the only place where either our data size or our throughput has grown beyond one partition, so being able to do cross-partition queries efficiently would be my number one request."
"There aren't any specific areas that need improvement, but if there were a way to achieve the right cosine similarity score without extensive testing, that would be very beneficial."
"It would be beneficial if Cosmos supported batch and real-time use cases to make the system more seamless."
"There are no particular factors that need improvement. There is a little bit of a learning curve with scaling workloads, but it works smoothly."
"They can implement a better backup system or alert system on Microsoft's end. We do receive notices for regular maintenance or updates, but sudden issues create significant problems."
 

Pricing and Cost Advice

"Faiss is an open-source solution."
"It is an open-source tool."
"The cost is the biggest limitation of this solution."
"Cost isn’t a big hurdle for us right now. The solution is not costly."
"Cosmos DB is a PaaS, so there are no upfront costs for infrastructure. There are only subscriptions you pay for Azure and things like that. But it's a PaaS, so it's a subscription service. The license isn't perpetual, and the cost might seem expensive on its face, but you have to look at the upkeep for infrastructure and what you're saving."
"We are not consuming so much yet since we are at the beginning of using this solution. I would rate the pricing of Microsoft Azure Cosmos DB a six out of ten."
"Pricing is one of the solution's main features because it is based on usage, scales automatically, and is not too costly."
"Pricing, at times, is not super clear because they use the request unit (RU) model. To manage not just Azure Cosmos DB but what you are receiving for the dollars paid is not easy. It is very abstract. They could do a better job of connecting Azure Cosmos DB with the value or some variation of that."
"The customer had a high budget, but it turned out to be a little bit cheaper than what they expected. I am not sure how much they have spent so far, but they are satisfied with the pricing."
"I would rate Cosmos DB's cost at seven out of ten, with ten being the highest."
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Top Industries

By visitors reading reviews
Financial Services Firm
15%
Comms Service Provider
10%
Manufacturing Company
10%
Computer Software Company
8%
Financial Services Firm
11%
Outsourcing Company
11%
Legal Firm
10%
Manufacturing Company
8%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
No data available
By reviewers
Company SizeCount
Small Business36
Midsize Enterprise24
Large Enterprise59
 

Questions from the Community

What is your experience regarding pricing and costs for Faiss?
I did not purchase FAISS through the AWS Marketplace because FAISS is an open-source product. My experience with pricing, setup cost, and licensing is straightforward, as there is no cost for acqui...
What needs improvement with Faiss?
I currently do not think there is anything to be improved based on our experience, as Faiss performs as we expected for our workflow. I would like to see improvement in the fact that FAISS currentl...
What is your primary use case for Faiss?
My main use case for FAISS is in a retrieval-augmented generation project using it with OpenAI, where we use FAISS to store our embeddings created by the Colbert model and for retrieval as well. In...
What is your experience regarding pricing and costs for Microsoft Azure Cosmos DB?
I have knowledge about the pricing, setup cost, and licensing aspect of Microsoft Azure Cosmos DB.
What needs improvement with Microsoft Azure Cosmos DB?
One thing which has troubled us is the cost model for Microsoft Azure Cosmos DB. It is comparatively very difficult to understand. Sometimes without any efficiency, the cost increases. The cost mod...
What is your primary use case for Microsoft Azure Cosmos DB?
I have been working with Microsoft Azure Cosmos DB for two years, and I have been working with the Azure ecosystem for four to five years.We use Microsoft Azure Cosmos DB because it provides a scal...
 

Comparisons

 

Also Known As

No data available
Microsoft Azure DocumentDB, MS Azure Cosmos DB
 

Overview

 

Sample Customers

1. Facebook 2. Airbnb 3. Pinterest 4. Twitter 5. Microsoft 6. Uber 7. LinkedIn 8. Netflix 9. Spotify 10. Adobe 11. eBay 12. Dropbox 13. Yelp 14. Salesforce 15. IBM 16. Intel 17. Nvidia 18. Qualcomm 19. Samsung 20. Sony 21. Tencent 22. Alibaba 23. Baidu 24. JD.com 25. Rakuten 26. Zillow 27. Booking.com 28. Expedia 29. TripAdvisor 30. Rakuten 31. Rakuten Viber 32. Rakuten Ichiba
TomTom, KPMG Australia, Bosch, ASOS, Mercedes Benz, NBA, Zero Friction, Nederlandse Spoorwegen, Kinectify
Find out what your peers are saying about Faiss vs. Microsoft Azure Cosmos DB and other solutions. Updated: September 2026.
916,240 professionals have used our research since 2012.