Best Open Source Vector Databases: A Comprehensive Guide

JD Prater

September 11, 2023

Table of Contents

Vector databases have quickly become a must-have in the tech world. Originally made to power search engines with smart algorithms, now they're also key for running cool AI projects, like those using LLMs.

These aren't your usual databases. Unlike the classic ones that store data in tables or the newer types that use JSON, vector databases are all about handling vectors — think of them as super-focused tools for specific AI tasks.

Vectors are like shortcuts that help AI understand and use data faster and smarter, coming from the intense training that machine learning goes through. So, when we talk about storing and finding data in the world of AI, vector databases are where it's at.

What's out there for folks looking to store these high-tech vectors, and how do you pick the right tool for your project? Before we dive into the best open-source vector databases and libraries that are making waves in 2024, let's break down what sets these solutions apart and why they're so cool for anyone diving into AI.

Open Source Vector Databases: An Overview

Let's kick things off by defining what exactly we mean by open source vector databases. Simply put, they are data storage systems that manage, store, and retrieve data in a vector format. As you can probably guess, these databases are open-source, meaning their source code is freely available and modifiable. This offers some considerable advantages, but we'll get to that later.

Now, why are vector databases so significant to the AI world? Well, they are designed for handling high-dimensional data, like the kind you often find in AI applications. From image processing to recommendation systems, these databases are the unsung heroes behind the scenes, making AI magic possible.

Let's break it down:

  • Manage: Open source vector databases handle data in its raw form, effectively organizing and managing it for the AI models to use.
  • Store: These databases store vector data, which can also include high-dimensional data coming from various AI applications.
  • Retrieve: Open source vector databases are particularly good at retrieving data efficiently, ensuring that AI models get the information they need, when they need it.

The great thing about open source vector databases is their flexibility. You can modify them to suit your specific needs, making them a powerful tool for AI developers. Plus, being open source, they provide a cost-effective solution for handling data in AI applications.

But with so many open source vector databases out there, which one should you choose for your AI project? Well, that's what we're going to explore next. So, get ready as we dive into the world of open source vector databases, and discover how they can enhance your AI applications.

Check out The 12 Best Vector Databases For AI Apps (Comparisons, Reviews, Demos, and Limitations)

How Do Open Source Vector Databases Work

Alright, now that we've seen why open source vector databases are great, let's look under the hood and understand how they work.

At the heart of it, open source vector databases manage data by using mathematical vectors. But wait a minute, what's a vector? In simple terms, a vector is a mathematical object that has both a direction and magnitude.

In the world of open source vector databases, these vectors are used to represent complex data, like images or text. Each piece of data is transformed into a vector in a high-dimensional space.

best vector database open source

Now comes the magic part. When you need to find similar pieces of data, the database doesn't have to sift through every single entry. Instead, it calculates the distance between vectors. The closer the vectors are, the more similar the data.

This approach is incredibly efficient and can handle large volumes of data much faster than traditional databases. Plus, because the software is open source, developers can fine-tune the algorithms to fit their specific needs.

In essence, open source vector databases turn the complex task of data management into a simple game of connect the dots. And who said data science couldn't be fun?

Check out the 14 Top Open Source Text Embedding Models

9 of the Best Open Source Vector Databases

Alright, let's jump right into the meat of the matter. In the world of open source vector databases, some names stand out for their performance, flexibility, and robustness.

Let's take a look at these top contenders:

1. Milvus

Launched by Zilliz, Milvus is a highly customizable, open source vector database that shines when it comes to handling large-scale data. It's an excellent choice when you need to work with vast amounts of data, thanks to its superb scalability. Milvus makes unstructured data search more accessible, and provides a consistent user experience regardless of the deployment environment.

milvus database architecture

2. Faiss

Developed by Facebook's AI Research team, Faiss is another impressive vector database that excels in high-dimensional vector search. It's known for its efficiency and speed, making it a great pick for time-sensitive applications. Faiss is a library for efficient similarity search and clustering of dense vectors. It contains algorithms that search in sets of vectors of any size, up to ones that possibly do not fit in RAM. It also contains supporting code for evaluation and parameter tuning. Faiss is written in C++ with complete wrappers for Python/numpy. Some of the most useful algorithms are implemented on the GPU.

3. Annoy (Approximate Nearest Neighbors Oh Yeah)

Annoy, created by Spotify, is a lightweight yet powerful database. It's designed for lightning-fast searches of large datasets, making it perfect for applications that need quick results. It’s a C++ library with Python bindings to search for points in space that are close to a given query point. It also creates large read-only file-based data structures that are mapped into memory so that many processes may share the same data.

annoy visualized
ANNOY visualized

4. Nmslib (Non-Metric Space Library)

Nmslib is a specialized open source vector database that focuses on non-metric space. It's a great choice for those unique projects that require a more niche solution. The goal of the project is to create an effective and comprehensive toolkit for searching in generic and non-metric spaces. Even though the library contains a variety of metric-space access methods, the main focus is on generic and approximate search methods, in particular, on methods for non-metric spaces. NMSLIB is possibly the first library with a principled support for non-metric space searching.

5. Qdrant

Qdrant (read: quadrant) is a vector similarity search engine and vector database.It provides a production-ready service with a convenient API to store, search, and manage points—vectors with an additional payloadQdrant is tailored to extended filtering support. It makes it useful for all sorts of neural-network or semantic-based matching, faceted search, and other applications.

qdrant database architecture

Qdrant is written in Rust 🦀, which makes it fast and reliable even under high load. See benchmarks.

6. Chroma

Chroma is the open-source embedding database. Chroma makes it easy to build LLM apps by making knowledge, facts, and skills pluggable for LLMs. Chroma is designed to be simple enough to get started with quickly and flexible enough to meet many use-cases. You can use your own embedding models, query Chroma with your own embeddings, and filter on metadata.

chroma database architecture

7. LanceDB

LanceDB is an open-source database for vector-search built with persistent storage, which greatly simplifies retrieval, filtering and management of embeddings. LanceDB's core is written in Rust and is built using Lance, an open-source columnar format designed for performant ML workloads. LanceDB APIs work seamlessly with the growing Python and Javascript ecosystem. Manipulate data with DataFrames, build models with Pydantic, store and query with LanceDB.

lancedb diagram

8. Vectra

Vectra is a local vector database for Node.js with features similar to Pinecone or Qdrant but built using local files. Each Vectra index is a folder on disk. There's an index.json file in the folder that contains all the vectors for the index along with any indexed metadata.  When you create an index you can specify which metadata properties to index and only those fields will be stored in the index.json file. All of the other metadata for an item will be stored on disk in a separate file keyed by a GUID.

Keep in mind that your entire Vectra index is loaded into memory so it's not well suited for scenarios like long term chat bot memory. Use a real vector DB for that.

9. Vespa

Vespa is an open-source platform for applications that need low-latency computation over large structured, text and vector data. is used to make AI-driven decisions using big data, in real time, at any scale, with unbeatable performance.

vespa architecture

Organizations use to solve problems such as structured, text, and vector search, and real-time recommendation, personalization and targeting.The platform is open source under an Apache 2.0 license.It can be downloaded from, or used as a serverless managed service at

Wrap up

Each of these databases brings something unique to the table. Your choice should depend on your specific needs. For instance, if you're working on a project that requires high-speed data retrieval, Annoy might be your best bet. On the other hand, if your project involves non-metric space, then Nmslib could be the perfect fit.

Remember, the best open source vector database for your project is the one that suits your requirements the best. So, take the time to understand each option, and make an informed choice. The right database could make all the difference in your AI application's performance. Stay tuned as we delve deeper into how these databases support scalable AI applications.

5 Benefits of Using Open Source Vector Databases

Let's get straight to the point: why should you care about open source vector databases? Well, there are plenty of reasons to love them, and here are some of the biggest benefits:

  1. Community Support: One major advantage of using open source tools is the large and active community behind them. This means you have a whole army of developers and users ready to help with any issues or improvements.
  2. Flexibility: Because open source vector databases are open to modification, you can tailor them to your specific needs. Want to add a new feature? No problem. Need to optimize the database for your unique data? Go ahead. It's your playground.
  3. Cost-effectiveness: No licensing fees, no subscription fees, no hidden costs. With open source, you get a powerful vector database without the hefty price tag. The only investment required is your time and effort.
  4. Transparency: With proprietary software, you're at the mercy of the vendor. But with open source vector databases, you can see exactly how they work. This transparency allows you to trust the software and to use it more effectively.
  5. Continuous Improvement: Open source vector databases are always evolving, thanks to the contributions from the community. This means you're always getting the latest features and improvements.
Two-Stage Semantic Search Engine
Two-Stage Semantic Search Engine with Graft

So, you see, open source vector databases are more than just a budget-friendly option. They're a powerful, flexible, and transparent tool that can make your data management and analysis much more efficient. And that's just scratching the surface. So, are you ready to dive a little deeper?

How to Choose the Right Open Source Vector Database for Your AI Project

Choosing the right open source vector database for your AI project can be a bit of a challenge, but don't worry—we're here to help!

  1. Analyze Your Needs - Before you start looking at different databases, take a moment to think about your project's needs. What kind of data will you be working with? How much data will you need to process? What are your performance expectations? Answering these questions will help you narrow down your options and find a database that suits your project.
  2. Evaluate the Features - Different open source vector databases offer different features. Some excel in speed and performance, while others offer better scalability or data protection. Make sure to evaluate these features based on your needs. Remember, the perfect database for your project should strike a balance between performance, scalability, and data protection.
  3. Consider the Community - Choosing an open source vector database is not just about the database itself. It's also about the community behind it. A strong, active community can provide valuable support and resources for your project. So, don't forget to check out the community when you're considering different databases.
  4. Test the Database - Finally, don't forget to test the database before making a decision. This will give you a firsthand experience of its performance and capabilities. Plus, it's a great way to see if the database is compatible with your project.

Choosing the right open source vector database is a crucial step towards the success of your AI project. So, take your time, do your research, and make an informed decision. After all, the future of your project depends on it!

Common Challenges and Solutions with Open Source Vector Databases

Onwards and upwards, my friend! As with everything in life, working with open source vector databases comes with its own set of challenges. But hey, don't worry! For every problem, there's a solution waiting in the wings. Let's explore a few of these.

Challenge #1: Complexity of setup

Yes, setting up an open source vector database can feel like trying to solve a Rubik's Cube sometimes. But here's the deal — you don't need to go it alone. There's a wealth of tutorials, guides, and community forums out there to help you navigate the setup process.

Challenge #2: Performance issues

Sometimes, your database might not perform as efficiently as you'd like. This could be due to inadequate resources, improper configuration, or even unoptimized queries. The solution? Monitor your database regularly, optimize your queries, and if needed, consider scaling up your resources.

Challenge #3: Lack of proper documentation

This is a common issue with open source projects. However, you'll find that most popular open source vector databases have robust documentation. And if that doesn't cut it, remember the community is always there to lend a helping hand.

Challenge #4: Data security

Open source doesn't mean insecure. However, it's up to you to ensure your data is safe. Implementing strong access controls, encrypting sensitive data, and regularly updating your database are just a few ways to bolster your data security.

Remember, challenges are just opportunities in disguise. So, take them in stride, learn from them, and let them shape you into a better user of open source vector databases. Onwards!

Navigating Open-Source Vector Databases

Q1: What are the key advantages of using an open-source vector database over commercial options?

Open-source vector databases offer several compelling advantages, including cost savings, as they are free to use and modify. They also foster innovation through community contributions, ensuring the software evolves rapidly.

Customization is another significant benefit, allowing developers to tailor the database to their specific needs. Additionally, open-source databases often have strong community support, providing a wealth of knowledge and resources for troubleshooting and optimization.

Q2: How do I evaluate and compare the performance of different open-source vector databases?

To effectively evaluate and compare open-source vector databases, consider factors like query response time, scalability, and accuracy. Benchmarks that simulate real-world scenarios are particularly useful. Additionally, review the documentation and community forums for insights on performance under various workloads. It's also beneficial to conduct your own testing with datasets relevant to your project to see how each database performs in terms of speed and resource consumption.

Q3: Can open-source vector databases integrate easily with existing machine learning and data processing pipelines?

Many open-source vector databases are designed with integration in mind, offering APIs and connectors for popular machine learning frameworks and data processing tools. Look for databases that support RESTful APIs, Python libraries, or Docker containers for easier integration. Checking the documentation or community forums for specific integration guides and examples can also be helpful.

Q4: What are some common use cases or applications that have successfully implemented open-source vector databases?

Open-source vector databases are used in a variety of applications, including recommendation systems, semantic text search, image and video retrieval, and anomaly detection. Successful implementations often involve enhancing user experience through more relevant search results or creating more efficient ways to navigate and analyze large datasets. Real-world examples include eCommerce platforms using vector databases for product recommendations and content platforms for personalized content discovery.

Q5: What are the challenges or limitations of using open-source vector databases, and how can they be mitigated?

Challenges include the need for specialized knowledge to optimize performance and scalability, as well as the ongoing maintenance required to keep the database secure and up-to-date. To mitigate these challenges, actively participate in community forums and workshops to gain insights and tips from other users. Documentation and tutorials can also be invaluable resources for best practices in deployment and optimization. Additionally, consider contributing to the project or sponsoring development to help improve the software and support ecosystem.

The Future Looks Bright

There you have it - a comprehensive guide to the world of open source vector databases. From understanding what they are, to how they work, key options, benefits, challenges, and what's on the horizon, we've covered the essentials.

These versatile, scalable databases are empowering cutting-edge AI applications across industries. With the ability to efficiently store, query, and relate complex high-dimensional data, they are opening up new possibilities in fields like natural language processing, recommendation systems, and beyond.

And with an engaged open source community continually improving these databases, they are sure to become even more capable and accessible. Challenges around scalability, data quality, and computing needs are being actively tackled.

The future looks bright for open source vector databases as researchers push boundaries and developers build on these robust foundations. Their unique superpowers look set to transform how we create intelligent systems and derive insights from data.

So get excited about what these technologies have in store! With an open source vector database as your ally, you too can build innovative AI applications that learn, reason, and interact with the world around them. The possibilities are endless - where will you point these databases next?

Graft: The Shortcut to a Full Production AI Platform

We just walked through the best open-source vector databases, and if you're like most developers, your mind is probably buzzing with possibilities. Open-source tools offer a world of flexibility and customization, but they also present a labyrinth of decisions, integrations, and potential pitfalls. As you stand at this crossroads, you might be wondering: Is there a way to harness the power of cutting-edge technology without getting lost in the complexity?

Enter Graft's Modern AI platform—engineered to simplify your journey through the intricate landscape of AI development. Let's explore why opting for our full-production AI system could be the smarter, faster, and ultimately more efficient route for your projects.

Graft's Full Production AI System
Graft's Full Production AI System

1. Seamless Integration

While open-source vector databases offer flexibility, they often require you to manually integrate them with other tools, models, and systems. Graft's Modern AI platform comes with pre-integrated components, allowing you to focus on building innovative solutions rather than wrestling with compatibility issues.

2. Speed to Market

Time is of the essence in today's fast-paced tech world. The time you'd spend piecing together multiple open-source tools could be better spent on refining your product and getting it to market. With Graft, you get a production-ready AI system out-of-the-box, significantly accelerating your time-to-market.

3. Cutting-Edge Technology

Graft's Modern AI platform is built on state-of-the-art technology, ensuring you're always ahead of the curve. You get access to the latest machine learning models, data processing tools, and analytics dashboards without the hassle of constant updates and patches.

4. Cost-Effectiveness

While open-source tools may seem cost-effective initially, the hidden costs of integration, maintenance, and scaling can quickly add up. Graft offers a cost-effective, scalable solution that grows with your needs, eliminating the need for constant tinkering and adjustments.

5. Security and Compliance

When you're piecing together multiple tools and systems, ensuring security and compliance can be a nightmare. Graft's platform is designed with enterprise-grade security measures and complies with industry standards, giving you peace of mind.

6. Expert Support

Navigating the complexities of AI can be challenging. With Graft, you're not alone. You get access to a team of experts dedicated to helping you succeed. Whether it's troubleshooting issues or optimizing performance, professional support is just a click away.

Final thoughts

While the allure of building your own AI system from various open-source components may seem appealing, the practical challenges are often underestimated. Graft's Modern AI platform offers a streamlined, efficient, and secure alternative that lets you focus on what you do best—innovating.

So, why spend countless hours juggling multiple tools when you can have a comprehensive, state-of-the-art AI system ready to deploy? Make the smart choice. Choose Graft.

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Last Updated

March 7, 2024

Further reading

JD Prater

Head of Marketing

JD writes about his experience using and building AI solutions. Outside of work, you'll find him spending time with his family, cycling the backroads of the Santa Cruz mountains, and surfing the local sandbars. Say hi on LinkedIn.

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