As businesses increasingly rely on big data and analytics, open source web crawlers provide an affordable way to extract valuable insights from the web. In this comprehensive guide, we will explore the top 15 open source web crawlers available today and provide expert advice on how to choose the right one for your needs.
What are Open Source Web Crawlers?
Web crawlers, also known as spiders or bots, are programs that systematically browse the internet and index web pages. As they crawl the web, they extract key data from websites in a structured format. This data can then be analyzed to uncover trends, patterns, and other useful information.
Open source web crawlers have publicly available source code that can be customized and extended as needed. Compared to proprietary crawlers, open source options offer several key benefits:
- Lower cost – Open source crawlers can be deployed and scaled at little to no licensing fees.
- No vendor lock-in – The code is owned by the user, not tied to any one vendor.
- Flexibility – The code can be modified and enhanced to meet specific needs.
- Community support – Open source projects often have an active user community that contributes ideas, fixes bugs, etc.
For businesses looking to leverage web data, open source crawlers provide a flexible and cost-effective solution. Next, let‘s explore some of the top options available today.
Top 15 Open Source Web Crawlers
Here are 15 leading open source web crawlers and their key features:
1. Apache Nutch
- Language: Java
- Systems: Windows, Mac, Linux
- GitHub
Apache Nutch is a popular open source crawler with robust web crawling capabilities. It can scale to massive data sets with its Hadoop-based architecture. Nutch also integrates well with Solr search server.
2. Apify SDK
- Language: JavaScript
- Systems: Windows, Mac, Linux
- GitHub
Apify SDK provides a scalable web crawling and scraping solution in JavaScript. It can handle complex sites with login forms, pagination, and more. The actor model simplifies deployments.
3. BUbiNG
- Language: Java
- Systems: Linux
- GitHub
BUbiNG (Bologna Unstructured Information Navigator and Gleaner) is optimized for crawling large domains thoroughly. It has political, temporal, and geographical crawling capabilities.
4. Heritrix
- Language: Java
- Systems: Linux
- GitHub
Heritrix is developed by the Internet Archive to document the web for its Wayback Machine. It respects robots.txt and has powerful extensibility features.
5. JSpider
- Language: Java
- Systems: Windows, Mac, Linux
- GitHub
JSpider is a lightweight, customizable crawler that can validate links, emails, and phone numbers during crawls. It has flexible options like regex URL filters.
6. Node Crawler
- Language: JavaScript
- Systems: Windows
- GitHub
Node Crawler offers event-driven crawling with Node.js. It can crawl asynchronously and handle sites behind logins. The code is clean and simple to customize.
7. Nokogiri
- Language: Ruby
- Systems: Windows, Mac, Linux
- GitHub
Nokogiri is a Ruby crawler that parses HTML and XML. It has a polished API and integrates with apps like Ruby on Rails. Nokogiri excels at extracting structured data.
8. Norconex HTTP Collector
- Language: Java
- Systems: Windows, Mac, Linux
- GitHub
Norconex offers a modular set of crawlers. The HTTP Collector one supports POST requests, cookies, and robots.txt. It also handles non-HTML formats like PDF.
9. OpenSearchServer
- Language: Java
- Systems: Windows, Mac, Linux
- GitHub
OpenSearchServer crawls websites and indexes them for search. It can integrate with machine learning for text analysis. Supports broad file formats.
10. Portia
- Language: JavaScript
- Systems: Windows, Mac, Linux
- GitHub
Portia allows visual scraping without coding. It generates extractors automatically once you annotate a site. Works well for complex sites.
11. PySpider
- Language: Python
- Systems: Windows
- GitHub
PySpider is designed for large-scale web crawling with Python. It includes a web UI and API for managing crawls. Integrates with MySQL, MongoDB, etc.
12. Scrapy
- Language: Python
- Systems: Windows, Mac, Linux
- GitHub
Scrapy is a popular Python crawler framework. It handles complex sites gracefully and has excellent documentation. Scrapy works nicely with Pandas and NumPy.
13. StormCrawler
- Language: Java
- Systems: Linux
- GitHub
StormCrawler runs crawls on an Apache Storm cluster for scalability. It has configurable policies by domain and content type.
14. Web Harvest
- Language: Java
- Systems: Windows, Mac, Linux
- SourceForge
Web Harvest handles complex sites with forms, JavaScript, cookies, etc. It provides a proxy rotator and browser engine. The GUI simplifies use.
15. WebSphinx
- Language: Java
- Systems: Windows, Mac, Linux
- JavaSource
WebSphinx offers visual programming for building crawlers. It automatically detects forms and lets you script complex workflows.
This covers some of the most popular and capable open source crawlers available today. When evaluating them, be sure to consider language and platform support based on your internal skills and resources.
How to Choose the Best Open Source Web Crawler
Selecting the right open source web crawler depends on your specific use case and technical environment. Here are some best practices to follow:
Define Your Crawling Requirements
First, outline your crawling goals and technical limitations:
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What types of sites do you need to crawl – standard web pages, Ajax-heavy sites, APIs?
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What data points need to be extracted – text, images, documents?
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What scale of crawling is needed – small websites or the entire internet?
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How often will crawls run – one-time, daily, or real-time?
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What technical skills does your team have to maintain the crawler?
The requirements will guide your technology choices. For example, a Java-based crawler may be preferable if your team knows Java already.
Evaluate Community Support
Since open source projects rely on community contributions, it‘s vital to assess the crawler‘s community:
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How active are forums, wikis, GitHub issues and pull requests?
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Are bugs being fixed and new features added regularly?
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Is professional support available if needed?
Strong community support ensures long-term viability of the crawler. Lively forums also provide tips for customizing the crawler to your needs.
Assess Extensibility & Maintenance
Also consider how easily the crawler can be adapted over time:
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Can the crawler handle new data formats or site designs in the future?
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Does it support adding customized extractors and plugins?
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Is the documentation thorough for developers maintaining the code?
Prioritize crawlers that provide extension points and clear code to minimize maintenance costs.
Consider Scalability Needs
If crawling large domains, assess how well each crawler can scale:
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Does the crawler run distributed across multiple servers?
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Can it integrate with cloud platforms like AWS, Google Cloud?
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Does the crawler handle resumability and retries gracefully?
For large crawls, scale and robustness are key factors to prevent outages.
By carefully evaluating your use case against crawler capabilities, you can determine the best open source option for your business.
Integrating Open Source Crawlers into Your Infrastructure
Once you‘ve selected an open source crawler, it takes architectural planning to integrate it smoothly:
- Crawler Servers – Provision sufficient Linux or Windows servers to run crawler instances. Cloud servers provide flexibility to scale as needed.
- Storage & Indexing – Crawl databases can grow large, so plan enterprise-grade storage. Search indexes may reside in Solr or Elasticsearch.
- Orchestration – Use Kubernetes or platform-specific schedulers to orchestrate and monitor crawls across servers.
- Security – Lock down crawler servers from outside access. Authenticate via VPN or private networking.
- Crawling Ethics – Respect robots.txt policies, rate limits, and site terms to crawl responsibly.
- Data Outputs – Push crawled data to data warehouses, lakes, or other BI tools for analysis.
IT teams will need to work closely with developers to launch crawlers in a secure, maintainable architecture.
When to Consider a Commercial Web Crawler
Despite their advantages, open source web crawlers require hands-on technical resources to operate and customize over time. Teams without sufficient in-house skills may prefer a commercial web crawling service.
With commercial crawlers, features to consider include:
- Intuitive control panels – Adjust crawling remotely through web UIs.
- turnkey data delivery – Crawlers push data to your desired business systems.
- Support services – Leaning on vendor expertise when needed.
- Latest technologies – Vendors keep pace with evolving sites and protocols.
- Cloud infrastructure – Crawlers run on proven managed cloud platforms.
Commercial solutions can provide a faster time-to-value when web data needs to be extracted urgently. They also minimize overhead for IT teams without deep crawler expertise.
Popular commercial options include:
- Import.io – Point-and-click data extraction.
- ScraperAPI – API for turning websites into JSON.
- Kimono – Generates APIs from websites via visual editor.
- Bright Data – Scalable proxy-based scraper.
- 80legs – Distributed web crawler as a service.
For the right use cases, commercial solutions can accelerate time-to-insight when web data is needed urgently.
Wrapping Up
Extracting web data can unlock transformative business insights when done right. As open source web crawlers mature, they provide a flexible and affordable path to large-scale scraping. By selecting the right crawler for your use case and infrastructure, you can start uncovering hidden trends and opportunities across the internet‘s endless data.