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Faiss vs Microsoft Azure Cosmos DB comparison

 

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
13th
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
109
Ranking in other categories
Database as a Service (DBaaS) (3rd), NoSQL Databases (2nd), Managed NoSQL Databases (1st)
 

Mindshare comparison

As of July 2026, in the Vector Databases category, the mindshare of Faiss is 4.3%, down from 6.2% compared to the previous year. The mindshare of Microsoft Azure Cosmos DB is 6.1%, up from 4.0% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Vector Databases Mindshare Distribution
ProductMindshare (%)
Microsoft Azure Cosmos DB6.1%
Faiss4.3%
Other89.6%
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

"The product has better performance and stability compared to one of its competitors."
"I used Faiss as a basic database."
"The most valuable feature of Microsoft Azure Cosmos DB is its real-time analytics capabilities, which allow for turnaround times in milliseconds. This is crucial for applications like fraud detection."
"The solution is scalable, and we intend to increase our usage."
"Specifically, we are using the MongoDB API, so we leverage it in that way. I like the flexibility that it offers. My team does not have to spend time building out database tables. We can get going fairly quickly with being able to read and write data into a MongoDB collection that is hosted inside Azure Cosmos DB."
"The best feature about Microsoft Azure Cosmos DB is its interface, which is awesome for accessing data."
"I like the scalability, there aren't any constraints for posting in the geolocation, and I also like the SQL architecture."
"The best features of Microsoft Azure Cosmos DB include the speed to query data; as long as you index properly, retrieving data is fast and lightweight."
"Microsoft Azure Cosmos DB helped improve our organization's search result quality significantly when we started using it about eight years ago."
"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."
 

Cons

"It could be more accessible for handling larger data sets."
"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."
"The UI needs enhancement. Unlike SQL, Cosmos DB's UI is not as straightforward, making it a bit challenging to use efficiently."
"The tool's pricing is expensive."
"The biggest problem is the learning curve and other database services like RDS."
"Continuing to educate customers on how they can take better advantage of Microsoft Azure Cosmos DB without having to completely rewrite their entire application paradigm would be beneficial. They can help them understand that there are multiple options to interact with it. They do not necessarily have to start from scratch. They can refactor their existing application to be able to use it better."
"Because there is no local way of doing things, Azure Cosmos DB will always be considered expensive."
"The customer service is lacking. We have a premier support agreement, but support is hit and miss."
"Areas of improvement for Microsoft Azure Cosmos DB include indexing. While it makes data retrieval easier, it also increases costs. If there's a better way to improve indexing at a lower cost, that would be really helpful, but that's the major point for now."
"I would like the speed of transferring data to be improved."
 

Pricing and Cost Advice

"Faiss is an open-source solution."
"It is an open-source tool."
"Because of the lack of understanding about RUs, the costs become unpredictable. It sometimes goes over the budget."
"Microsoft Azure Cosmos DB pricing is based on RUs. Reading 1 KB document costs one RU, whereas writing one document costs five RUs. Pricing for querying depends on the complexity of the query. If you increase the document size, it will automatically increase the RU cost."
"The pricing and licensing model was initially difficult to understand, but as soon as I learned what was going on and how it was priced, it was pretty easy."
"Microsoft Azure Cosmos DB's licensing costs are monthly."
"Microsoft provides fair pricing."
"Cosmos DB's pricing structure has significantly improved in recent months, both in terms of its pricing model and how charges are calculated."
"The pricing model of Microsoft Azure Cosmos DB is a bit complex."
"With heavy use, like a large-scale IoT implementation, you could easily hit a quarter of a million dollars a month in Azure charges if Cosmos DB is a big part of it."
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Top Industries

By visitors reading reviews
Financial Services Firm
15%
Comms Service Provider
9%
Manufacturing Company
9%
Computer Software Company
9%
Financial Services Firm
12%
Legal Firm
11%
Comms Service Provider
8%
Manufacturing Company
8%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
No data available
By reviewers
Company SizeCount
Small Business33
Midsize Enterprise22
Large Enterprise58
 

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?
Microsoft Azure Cosmos DB's pricing model has aligned with my budget expectations because I can tune the RU as I need to, which helps a lot. Microsoft Azure Cosmos DB's dynamic auto-scale or server...
What needs improvement with Microsoft Azure Cosmos DB?
I have not utilized Microsoft Azure Cosmos DB multi-model support for handling diverse data types. I'm not in the position to decide if clients will use Microsoft Azure Cosmos DB or any other datab...
What is your primary use case for Microsoft Azure Cosmos DB?
We have a very large team of developers who develop a solution for our customers. In the part where they need some infrastructure on Microsoft Azure, we deploy entire environments of different type...
 

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: June 2026.
904,928 professionals have used our research since 2012.