Legal research is one of the most important aspects of many legal cases. After all, without legal research, law firms have nothing to rely on to support their arguments. The question, though, is where to look for that support when you want to find the best sources.

These days, there are several legal solutions and research tools on the market, ranging from subscription services to free online resources. The following is a rundown of some of today’s most popular legal research tools for law firms.

LexisNexis. One of the biggest names in the legal research game for decades, LexisNexis is one of the most comprehensive research platforms on the market. Beyond legal research, they offer a wealth of business information and other intelligence as well. Accessing LexisNexis requires a subscription, and they offer different plans depending on what you need.

Westlaw/Thomson Reuters. Westlaw has been another big name on the legal research scene for several decades. This is also a paid subscription service, with different packages available. Westlaw is just one piece of the Thomson Reuters universe of research tools that delve deeper into legal research and other industry knowledge – other popular products include Westlaw Edge and Practical Law, which specializes in legal know-how.

PACER. Officially created by the federal judiciary, PACER is a public access site where you can find docket information from federal appellate, district, and bankruptcy courts. You’ll need to create login credentials, and if you find something you like, you pay a minimal per-page or per-document fee to download it.

Court Websites. Nearly every state court system has a website these days, and they offer differing degrees of searchability. For basic case information on parties or judges, this is a great place to start. Because each state website is so different, you’ll want to see what’s available in any given jurisdiction you’re focusing on.

Bar Association Legal Research Tools. Most state bar associations offer free access to legal research tools for their members. Depending on the state, this is likely offered through either the Casemaker or Fastcase platforms. Every bar association differs in terms of the access and features it offers, so check with yours to see what your options are. If you’re not a bar association member, both platforms can be accessed under various payment or subscription plans.

The Public Library of Law (PLoL). This is a free online database created and maintained by Fastcase. Here you can search for case law and check case citations, though not everything you can find on Fastcase is available in the free resource. You’ll have to register before you use the service for the first time.

Google Scholar. In 2004, Google decided to get into the legal research game, and the result was Google Scholar. As the name implies, Google Scholar is aimed at finding more scholarly resources than you’ll get with a typical Google search, though the interface functions essentially the same way, making it a highly intuitive tool. On the plus side, Google Scholar is free, but that means it comes with its limitations. You can’t be sure you’ll find everything that you’d find on LexisNexis or Westlaw and you won’t have indicators of whether or not your sources are good law, but this powerful tool is a good place to start your research.

FindLaw. Another free resource, FindLaw is best used as a jumping-off point for your legal research. You won’t necessarily find a wealth of comprehensive court decisions or journal articles like you will on the other sites – FindLaw’s focus is on giving you general overviews of a wide range of legal topics. While it’s useful for familiarizing yourself with new areas of law, always make sure that the information holds true for your jurisdiction.

Justia. Also free, Justia provides access to case law, codes, regulations, and legal information like articles and legal blogs. This is another good place for when you just need a brief overview of an area of law or are figuring out how to focus your research.

While these are some of the most popular legal research tools for law firms today, this list is far from exhaustive. As technology continues to evolve, lawyers will only have more legal solutions to rely on for conducting legal research in the future.

Be aware, though, that you generally get what you pay for – expensive subscription services will offer far more in the way of resources and helpful tools than free public databases. Resources that are sufficient for getting yourself up to speed may not be suitable for providing client advice or preparing court documents. Figure out what the purpose of your legal research is, and then find the tools that are right for you.