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for an extremely fast and reliable patent download

Useful links

Patent databases
Esp@cenet - The free, online EPO database
European Publication Server - The primary source of information on published EP patent applications and granted EP patents
Depatisnet - Electronic patent document archive of the DPMA, with roughly 66 million patent documents worldwide
Patent Electronic Business Center (USPTO) - Search tool for US patents and published applications
Swissreg - Swiss register of patents (including SPC), trademarks, designs and topographies
Patentscope - WIPO search tool for international patent applications

Online services
Register Plus (Epoline) - Online european patent register and online public file inspection
Patent Application Information Retrieval (PAIR) - Information regarding US patent application status

Inpadoc (raw data resources)
Inpadoc homepage - EPO collection of bibliographic data from over 70 countries and legal status data from more than 40 patent authorities
Coverage - Useful tables and statistics, coverage and codes

Classification
European patent classification (ECLA)
International patent classification (IPC)
United States patent classification (USPC)
FT-Terms | FI classification (Japanese classification)

Patent offices and institutions
European Patent Office (EPO)
World Intellectual Property Organisation (WIPO)
German patent and trademark office (Deutsches Patent- und Markenamt)
United States Patent and Trademark Office
Swiss Federal Institute of Intellectual Property
Patent offices of EPO member states
Other patent offices

Other useful information
List of legal status codes (Delphion)
List of kind codes (Delphion)
Glossary of patent terms (Delphion)