package_index.json specification

Starting from version 1.6.4 the Boards Manager of the Arduino IDE can be used to automatically install support for 3^rd party hardware by simply entering an URL in the File > Preferences dialog. The URL must be provided by the 3^rd party hardware producer and should point to a JSON file that contains an index of the boards available to install and the location of the installation archives. Boards Manager also allows easy updates of installed Boards when new versions are released.

Naming of the JSON index file¶

The IDE may use many different index files coming from different vendors, so each vendor should name his own index file in a way that won't conflict with others. The file must be named as follows:

package_YOURNAME_PACKAGENAME_index.json

The prefix package_ and the postfix _index.json are mandatory (otherwise the index file is not recognised by the IDE) while the choice of YOURNAME_PACKAGENAME is left to the packager. We suggest using a domain name owned by the packager. For example:

package_arduino.cc_index.json

or

package_example.com_avr_boards_index.json

The index URL is periodically checked for updates so expect a constant flow of downloads (proportional to the number of active users).

JSON Index file contents¶

The root of the JSON index is an array of packages:

{
  "packages": [
      PACKAGE_XXXX
   ]
}

3^rd party vendors should use a single PACKAGE_XXXX that is a dictionary map with the vendor's metadata, a list of PLATFORMS and a list of TOOLS. For example:

{
  "name": "arduino",
  "maintainer": "Arduino LLC",
  "websiteURL": "http://www.arduino.cc/",
  "email": "packages@arduino.cc",

  "platforms": [
      PLATFORM_AVR,
      PLATFORM_ARM,
      PLATFORM_XXXXX,
      PLATFORM_YYYYY,
  ],

  "tools": [
      TOOLS_COMPILER_AVR,
      TOOLS_UPLOADER_AVR,
      TOOLS_COMPILER_ARM,
      TOOLS_XXXXXXX,
      TOOLS_YYYYYYY,
   ],
}

The metadata fields are:

name: the folder used for the installed cores. The vendor folder name of the installed package is determined by this field
maintainer: the extended name of the vendor that is displayed on the Boards Manager GUI
websiteURL: the URL to the vendor's website, appears on the Boards Manager as a "More info" link
email: the email of the vendor/maintainer

Now, before looking at PLATFORMS, let's explore first how TOOLS are made.

Tools definitions¶

Each tool describes a binary distribution of a command line tool. A tool can be:

a compiler toolchain
an uploader
a file preprocessor
a debugger
a program that performs a firmware upgrade

basically anything that can run on the user's host PC and do something useful.

For example, Arduino uses two command line tools for the AVR boards: avr-gcc (the compiler) and avrdude (the uploader).

Tools are mapped as JSON in this way:

        {
          "name": "avr-gcc",
          "version": "4.8.1-arduino5",
          "systems": [
            {
              "host": "i386-apple-darwin11",
              "url": "http://downloads.arduino.cc/tools/avr-gcc-4.8.1-arduino5-i386-apple-darwin11.tar.bz2",
              "archiveFileName": "avr-gcc-4.8.1-arduino5-i386-apple-darwin11.tar.bz2",
              "size": "24437400",
              "checksum": "SHA-256:111b3ef00d737d069eb237a8933406cbb928e4698689e24663cffef07688a901"
            },
            {
              "host": "x86_64-linux-gnu",
              "url": "http://downloads.arduino.cc/tools/avr-gcc-4.8.1-arduino5-x86_64-pc-linux-gnu.tar.bz2",
              "archiveFileName": "avr-gcc-4.8.1-arduino5-x86_64-pc-linux-gnu.tar.bz2",
              "size": "27093036",
              "checksum": "SHA-256:9054fcc174397a419ba56c4ce1bfcbcad275a6a080cc144905acc9b0351ee9cc"
            },
            {
              "host": "i686-linux-gnu",
              "url": "http://downloads.arduino.cc/tools/avr-gcc-4.8.1-arduino5-i686-pc-linux-gnu.tar.bz2",
              "archiveFileName": "avr-gcc-4.8.1-arduino5-i686-pc-linux-gnu.tar.bz2",
              "size": "25882375",
              "checksum": "SHA-256:7648b7f549b37191da0b0be53bae791b652f82ac3cb4e7877f85075aaf32141f"
            },
            {
              "host": "i686-mingw32",
              "url": "http://downloads.arduino.cc/tools/avr-gcc-4.8.1-arduino5-i686-mingw32.zip",
              "archiveFileName": "avr-gcc-4.8.1-arduino5-i686-mingw32.zip",
              "size": "46044779",
              "checksum": "SHA-256:d4303226a7b41d3c445d901b5aa5903458def3fc7b7ff4ffef37cabeb37d424d"
            }
          ]
        },

The field name and version are respectively the name and version of the tool. Each tool is uniquely identified by the triple (vendor, name, version) and there can be many different versions of the same tool available at the same time, for example:

(arduino, avr-gcc, 4.8.1-arduino2)
(arduino, avr-gcc, 4.8.1-arduino3)
(arduino, avr-gcc, 4.8.1-arduino5)
(arduino, avrdude, 5.11)
(arduino, avrdude, 6.0)
(arduino, avrdude, 6.1)
.....

Each tool version may come in different build flavours for different OS. Each flavour is listed under the systems array. In the example above avr-gcc comes with builds for:

Linux 64-bit (x86_64-linux-gnu),
Linux 32-bit (i686-linux-gnu),
Windows (i686-mingw32),
Mac (i386-apple-darwin11)

The IDE will take care to install the right flavour based on the host value, or fail if a needed flavour is missing.
Note that the IDE does not use this information to select the toolchain during verify. If you want the IDE to use this specific version you should use the notation {runtime.tools.TOOLNAME-VERSION.path} in the platform.txt.

The other fields are:

url: the download URL of the tool's archive
archiveFileName: the name of the file saved to disk after the download (some web servers don't provide the filename through the HTTP request)
size: the size of the archive in bytes
checksum: the checksum of the archive, used to check if the file has been corrupted. The format is ALGORITHM:CHECKSUM, currently MD5, SHA-1,SHA-256 algorithm are supported, we recommend SHA-256. On *nix or MacOSX you may be able to use the command shasum -a 256 filename to generate SHA-256 checksums. There are many free options for Windows including md5deep, there are also online utilities for generating checksums.

How a tool's path is determined in platform.txt¶

When the IDE needs a tool it downloads the corresponding archive file and unpacks the content into a private folder that can be referenced from platform.txt using one of the following properties:

{runtime.tools.TOOLNAME-VERSION.path}
{runtime.tools.TOOLNAME.path}

For example to obtain the avr-gcc 4.8.1 folder we can use {runtime.tools.avr-gcc-4.8.1-arduino5.path} or {runtime.tools.avr-gcc.path}.

Platforms definitions¶

Finally, let's see how PLATFORMS are made.

        {
          "name": "Arduino AVR Boards",
          "architecture": "avr",
          "version": "1.6.6",
          "category": "Arduino",
          "help": {
            "online": "http://www.arduino.cc/en/Reference/HomePage"
          },
          "url": "http://downloads.arduino.cc/cores/avr-1.6.6.tar.bz2",
          "archiveFileName": "avr-1.6.6.tar.bz2",
          "checksum": "SHA-256:08ad5db4978ebea22344edc5d77dce0923d8a644da7a14dc8072e883c76058d8",
          "size": "4876916",
          "boards": [
            {"name": "Arduino Yún"},
            {"name": "Arduino Uno"},
            {"name": "Arduino Diecimila"},
            {"name": "Arduino Nano"},
            {"name": "Arduino Mega"},
            {"name": "Arduino MegaADK"},
            {"name": "Arduino Leonardo"},
          ],
          "toolsDependencies": [
            { "packager": "arduino", "name": "avr-gcc", "version": "4.8.1-arduino5" },
            { "packager": "arduino", "name": "avrdude", "version": "6.0.1-arduino5" }
          ]
        },

Each PLATFORM describes a core for a specific architecture. The fields needed are:

name: the extended name of the platform that is displayed on the Boards Manager GUI
architecture: is the architecture of the plaftorm (avr, sam, etc...). It must match the architecture of the core as explained in the Arduino platform specification
version: the version of the platform.
category: this field is reserved, a 3^rd party core must set it to Contributed
help/online: is a URL that is displayed on the Boards Manager as an "Online Help" link
url, archiveFileName, size and checksum: metadata of the core archive file. The meaning is the same as for the TOOLS
boards: the list of boards supported (note: just the names to display on the GUI! the real boards definitions are inside boards.txt inside the core archive file)
toolsDependencies: the tools needed by this core. Each tool is referenced by the triple (packager, name, version) as previously said. Note that you can reference tools available in other packages as well.

The version field is validated by both Arduino IDE and JSemVer. Here are the rules Arduino IDE follows for parsing versions (source):

Split the version at the - character and continue with the first part.
If there are no dots (.), parse version as an integer and form a Version from that integer using Version.forIntegers
If there is one dot, split version into two, parse each part as an integer, and form a Version from those integers using Version.forIntegers
Otherwise, simply parse version into a Version using Version.valueOf

Note: if you miss a bracket in the JSON index, then add the URL to your Preferences, and open Boards Manager it can cause the Arduino IDE to no longer load until you have deleted the file from your arduino15 folder.

Example JSON index file¶

{
  "packages": [
    {
      "name": "myboard",
      "maintainer": "Jane Developer",
      "websiteURL": "https://github.com/janedeveloper/myboard",
      "email": "jane@janedeveloper.org",
      "help": {
        "online": "http://janedeveloper.org/forum/myboard"
      },
      "platforms": [
        {
          "name": "My Board",
          "architecture": "avr",
          "version": "1.0.0",
          "category": "Contributed",
          "help": {
            "online": "http://janedeveloper.org/forum/myboard"
          },
          "url": "https://janedeveloper.github.io/myboard/myboard-1.0.0.zip",
          "archiveFileName": "myboard-1.0.0.zip",
          "checksum": "SHA-256:ec3ff8a1dc96d3ba6f432b9b837a35fd4174a34b3d2927de1d51010e8b94f9f1",
          "size": "15005",
          "boards": [
            {"name": "My Board"},
            {"name": "My Board Pro"}
          ],
          "toolsDependencies": [
            {
              "packager": "arduino",
              "name": "avr-gcc",
              "version": "4.8.1-arduino5"
            },
            {
              "packager": "arduino",
              "name": "avrdude",
              "version": "6.0.1-arduino5"
            }
          ]
        },
        {
          "name": "My Board",
          "architecture": "avr",
          "version": "1.0.1",
          "category": "Contributed",
          "help": {
            "online": "http://janedeveloper.org/forum/myboard"
          },
          "url": "https://janedeveloper.github.io/myboard/myboard-1.0.1.zip",
          "archiveFileName": "myboard-1.0.1.zip",
          "checksum": "SHA-256:9c86ee28a7ce9fe33e8b07ec643316131e0031b0d22e63bb398902a5fdadbca9",
          "size": "15125",
          "boards": [
            {"name": "My Board"},
            {"name": "My Board Pro"}
          ],
          "toolsDependencies": [
            {
              "packager": "arduino",
              "name": "avr-gcc",
              "version": "4.8.1-arduino5"
            },
            {
              "packager": "arduino",
              "name": "avrdude",
              "version": "6.0.1-arduino5"
            }
          ]
        }
      ],
      "tools":[]
    }
  ]
}

In the example there is one PACKAGE, My Board. The package is compatible with the AVR architecture. There are two versions of the PACKAGE, 1.0.0 and 1.0.1. No TOOLS needed to be installed so that section was left blank.

Here is the Boards Manager entry created by the example: Boards Manager screenshot

Installation archive structure¶

The installation archives contain the Board support files. Supported formats are .zip, .tar.bz2, and .tar.gz.

The folder structure of the core archive is slightly different from the standard manually installed Arduino 1.5+ compatible hardware folder structure. You must remove the architecture folder(e.g., avr or arm), moving all the files and folders within the architecture folder up a level.

After adding Boards Manager support for your boards, please share the JSON index file URL on the Unofficial list of 3^rd party boards support urls.