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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
14th
Average Rating
8.0
Reviews Sentiment
3.3
Number of Reviews
3
Ranking in other categories
Open Source Databases (13th)
Microsoft Azure Cosmos DB
Ranking in Vector Databases
1st
Average Rating
8.2
Reviews Sentiment
7.0
Number of Reviews
112
Ranking in other categories
Database as a Service (DBaaS) (3rd), NoSQL Databases (1st), Managed NoSQL Databases (1st)
 

Mindshare comparison

As of September 2026, in the Vector Databases category, the mindshare of Faiss is 4.2%, down from 5.6% compared to the previous year. The mindshare of Microsoft Azure Cosmos DB is 5.8%, up from 4.7% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Vector Databases Mindshare Distribution
ProductMindshare (%)
Microsoft Azure Cosmos DB5.8%
Faiss4.2%
Other90.0%
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 solution is user friendly and Microsoft's technical support is good."
"Microsoft Azure Cosmos DB is very fast. Data retrieval and data storage are very quick."
"It gives us a lot of flexibility. The scaling is instantaneous as well. You immediately have all the resources available."
"I would rate it a ten out of ten for stability."
"It handles large-scale operations efficiently, such as tracking views, logs, or events."
"It is a scalable product."
"Overall, I find Microsoft Azure Cosmos DB to be cost-effective, with a good return on investment (ROI)."
"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."
 

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 could be more accessible for handling larger data sets."
"It would be beneficial if I could set a parameter and see different query mechanisms being run."
"Currently, I have no suggestions for enhancement or new implementations in Microsoft Azure Cosmos DB. However, the cost can sometimes be high, especially during cross-partition queries with large data amounts."
"Microsoft Azure Cosmos DB can be improved by providing more fine-grained control over certain aspects, such as connections and threads. There could be more control over how many connections are made."
"Sometimes, the solution's access request takes time, which should be improved."
"Because there is no local way of doing things, Azure Cosmos DB will always be considered expensive."
"The current data analytics of Cosmos DB is inefficient for large-scale queries due to its transactional design."
"I have to say technical support is not very good as it takes too long. Sometimes it can take them two or three days to respond to your ticket."
"Firstly, having a local development emulator or simulator for Azure Cosmos DB would be beneficial. It would be very handy to have a Docker container that developers can use locally."
"A couple features that would help me in architectural solutions would be customizable architecture or customizable documentation, which both Microsoft Azure or Microsoft Teams can provide."
 

Pricing and Cost Advice

"It is an open-source tool."
"Faiss is an open-source solution."
"Everything could always be cheaper. I like that Cosmos DB allows us to auto-scale instead of pre-provisioning a certain capacity. It automatically scales to the demand, so we only pay for what we consume."
"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."
"Because of the lack of understanding about RUs, the costs become unpredictable. It sometimes goes over the budget."
"The price of Microsoft Azure Cosmos DB could be a bit lower."
"Cosmos DB is expensive, and the RU-based pricing model is confusing. Although they have a serverless layer, there are deficiencies in what I can define and assign to a database. Estimating infrastructure needs is not straightforward, making it challenging to manage costs."
"Microsoft Azure Cosmos DB is moderately priced, where it is neither expensive nor cheap."
"Microsoft Azure Cosmos DB's licensing costs are monthly."
"The tool is not expensive."
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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
10%
Legal Firm
10%
Manufacturing Company
7%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
No data available
By reviewers
Company SizeCount
Small Business35
Midsize Enterprise24
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?
I have knowledge about the pricing, setup cost, and licensing aspect of Microsoft Azure Cosmos DB.
What needs improvement with Microsoft Azure Cosmos DB?
I would see improvements in Microsoft Azure Cosmos DB, particularly concerning integration with more tiers. They should integrate products like IBM Watson for analytics and offer more options for e...
What is your primary use case for Microsoft Azure Cosmos DB?
I have worked with databases like Azure SQL Database, Cosmos DB, and PostgreSQL. We had a migration where our customer wanted solutions like Microsoft Azure Cosmos DB, where they desired high avail...
 

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: August 2026.
912,801 professionals have used our research since 2012.