JOSM is an extensible editor for ​OpenStreetMap (OSM) written in ​Java 6. Currently it supports loading stand-alone GPX tracks and GPX track data from the OSM database as well as loading and editing existing nodes, ways, metadata tags and relations from the OSM database. It is open source and licensed under GPL​.
Launch josm.jnlp (version 19253) recommended version, all platforms, automatic update (​Web Start)
Download josm-tested.jar (version 19253) all platforms (how to run)
Windows installer (version 19253)
Mac OS X package (version 19253). Users of Mountain Lion see Download
Latest development version (19265, josm-latest.jar) , Ubuntu package repository and other download options.

What has been changed recently?

• Startup notes (most important changes)
• Summarized changelog (nicely summarized)
• SVN changelog (very detailed)

Extensions

• Plugins (installation instructions)
• Presets (installation instructions)
• Rules (installation instructions)
• Styles (installation instructions)
• Backgrounds (installation instructions)

Getting Started | Help

• Comprehensive introduction on the ​OpenStreetMap wiki.
• The official help system / documentation (can be reached with <F1> from within JOSM).
• Tutorial on ​flossmanuals.net.
• Ask members of the OpenStreetMap community on
  • the ​OSM-forum
  • various ​OSM mailing lists (e.g. ​talk and ​newbies, ​list overview)
  • the ​OSM IRC channel, including our ​own channel
• HowTos and some video tutorials (mostly outdated)

Found a bug? | Have an idea? | Make a suggestion?

• Please report any bug found: Create a new ticket. When reporting a bug, please include the first three blocks of the status report (Help -> Show status report).
• Discuss ideas and suggestions also in the bug tracker, on the ​josm-dev mailing list, or on the ​#josm IRC channel.

Contribute

• Use JOSM
  • Report bugs, discuss ideas, think of possible enhancements (see above).
• Participate in bug tracking
  • Review bugs, up/down vote tickets, find duplicates, test bugs, add more descriptive texts.
• Correct/update/extend the online help
  • Unify all JOSM-related Wiki pages and join them with the online help.
• Translate program/documentation.
• Design fancy new icons.
• Write code – get the code and write patches …
  • get the code
  • See developers guide for build instructions and other details.

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This site

• This site is a combined online help and bug tracking system for JOSM and JOSM plugins.
• No login is required to use this site (neither for reading nor for changes to wiki or bug tracker).
• A login has the following advantages:
  • The JOSM applet can store settings on the server.
  • Mail is sent for changes in your own bug tracker tickets. This is possible by entering an e-mail as user name in the tickets, too, but then be aware that the address is openly visible and you are unable to change that later.
  • Page settings are remembered (e.g. input field size and a lot of other stuff).
• Logins which have no e-mail address or which have not been used at least once are automatically deleted.
• Logins to edit the OpenStreetMap database are separate from the logins on this server.
• The secured HTTPS version of this site uses a SSL certificate with the SHA1 fingerprint C5:8A:CF:54:15:7D:37:1F:21:6D:5D:92:B4:B4:FA:3A:3C:AA:14:6C.

Contact

Server sponsored by:

• For problems, ideas, suggestions use the bug tracker.
• The volunteers creating JOSM can be reached using the ​josm-dev mailing list or the ​#josm IRC chat.
• If you use social networks, see our ​Facebook and Google+ pages.
• The server running this service is operated by ​FOSSGIS society.