Before filing a patent application, it is important to inform yourself about the current state of the art and the respective patents which exist in that field.

Patents speak their own language, they are not always easy to understand. Thus, after a self-created overview, it is often recommended to dig deeper into the existing literature and seek the help of a patent attorney. Keep the following questions in mind when doing your due diligence: In what aspects does your invention go beyond the state of the art? How can your knowledge, in general, be protected considering the state of the art?



A very good starting point is the free online software Octimine. With the basic version, you can analyze patent documents of the EPO, the US Patent Office and the WIPO. Highly recommended if you have a technology description available as short text or publication numbers of similar patents and you want to identify other similar patent documents.

  • Free of charge, easy to use, and very precise results
  • Very quick first overview of the patent landscape
  • Diagrammed reports alleviate analysis
  • Semantic search algorithms
Octimine Logo

Moreover, also Patent offices provide comprehensive information about the patent stock in online databases. Here, you will find an evaluation of the most important patent data search engines:



The European Patent Register contains information about all EPO patent applications in great detail. You should use this database, if you are only looking for EP applications and are seeking in-depth information. This database however would not be appropriate, when the goal is to appraise the worldwide state of the art.

  • Comprehensive data, including legal status and even correspondence with the office
  • Applications in different languages, search function mainly in English
  • Oftentimes, patent attorneys are mentioned as representatives
  • EP patents only
European Patent Register



Espacenet offers access to more than 80 million patent documents worldwide. This database is a good choice, if you want to analyze the state of the art. You can search in English terms only, while results can automatically be translated into more than 30 languages including Asian languages such as Chinese or Japanese.

  • Impressive, worldwide database with more than 80 million entries
  • Information about patent families show geographical scope of patent protection
  • Direct access to automated document translation called “patent translate”
  • But: Keywords can be entered in English only


Use this database, if you are looking for utility models and design patents in addition to patents. The title of patents can be be entered in German only.

  • For patents (-1981), utility models, design patents and trademarks
  • Information about the state of the application process
  • Certain search fields have to be chosen
  • German keywords only


DEPATISnet is the internal search engine for DPMA patent examiners. More than 60 million patents are covered and can give a good overview about English synonyms, if German technical terms are known.

  • Large database
  • Search function in German, English and other languages
  • No translation possible
  • Search fields have to be defined


PATENTSCOPE contains more than 30 million patent applications including 2.2 million PCT applications. It is an interesting database, because some rare (e.g. Japanese and Russian) patent documents are incorporated. Keywords can be prompted in 12 languages and will be translated automatically.

  • Extensive database
  • Language function translates in 12 languages (so called CLIR function)
  • (Limited) graphical illustration capabilities for results


Google Patent Search scans EPO and USPTO data. This allows for a large number of findings, however, to some extent of questionable quality. It is useful as a first check of the state of the art, because the algorithm operates in many different languages and proposes similar patents.

  • High number of hits, sometimes inappropriate results
  • Direct translation of search results possible
  • A state of the art operation can select similar patents
Google Patent Search

The preceding evaluation shows that there is no perfect patent data search engine which attains every single goal.

You should choose the tool that fits your aims and needs. You will experience that you will have to use more than one search tool. Starting with Google Patent Search and PATENTSCOPE, followed by DEPATISnet and Espacenet, and completing the search with European Patent Register and DPMAregister is in most cases the ideal search strategy.

In most cases, a reliable search should be conducted by a patent attorney or a company specialized on patent document research.