package_index.json specification
Introduced in Arduino IDE 1.6.4, Boards Manager makes it easy to install and update Arduino platforms. In order to provide Boards Manager installation support for a platform, a JSON formatted index file must be published. This is the specification for that file.
Boards Manager functionality is provided by Arduino CLI, Arduino IDE, and Arduino Pro IDE.
Naming of the JSON index file¶
Many different index files coming from different vendors may be in use, so each vendor should name their 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
Arduino development software) 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]
}
3rd 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 fieldmaintainer: the extended name of the vendor that is displayed on the Arduino IDE/Pro IDE's Boards Manager GUIwebsiteURL: the URL to the vendor's website, appears on the Arduino IDE/Pro IDE's Boards Manager as a "More info" linkemail: 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": "7.3.0-atmel3.6.1-arduino7",
"systems": [
{
"size": "34683056",
"checksum": "SHA-256:3903553d035da59e33cff9941b857c3cb379cb0638105dfdf69c97f0acc8e7b5",
"host": "arm-linux-gnueabihf",
"archiveFileName": "avr-gcc-7.3.0-atmel3.6.1-arduino7-arm-linux-gnueabihf.tar.bz2",
"url": "http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-arm-linux-gnueabihf.tar.bz2"
},
{
"size": "38045723",
"checksum": "SHA-256:03d322b9df6da17289e9e7c6233c34a8535d9c645c19efc772ba19e56914f339",
"host": "aarch64-linux-gnu",
"archiveFileName": "avr-gcc-7.3.0-atmel3.6.1-arduino7-aarch64-pc-linux-gnu.tar.bz2",
"url": "http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-aarch64-pc-linux-gnu.tar.bz2"
},
{
"size": "36684546",
"checksum": "SHA-256:f6ed2346953fcf88df223469088633eb86de997fa27ece117fd1ef170d69c1f8",
"host": "x86_64-apple-darwin14",
"archiveFileName": "avr-gcc-7.3.0-atmel3.6.1-arduino7-x86_64-apple-darwin14.tar.bz2",
"url": "http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-x86_64-apple-darwin14.tar.bz2"
},
{
"size": "52519412",
"checksum": "SHA-256:a54f64755fff4cb792a1495e5defdd789902a2a3503982e81b898299cf39800e",
"host": "i686-mingw32",
"archiveFileName": "avr-gcc-7.3.0-atmel3.6.1-arduino7-i686-w64-mingw32.zip",
"url": "http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-i686-w64-mingw32.zip"
},
{
"size": "37176991",
"checksum": "SHA-256:954bbffb33545bcdcd473af993da2980bf32e8461ff55a18e0eebc7b2ef69a4c",
"host": "i686-linux-gnu",
"archiveFileName": "avr-gcc-7.3.0-atmel3.6.1-arduino7-i686-pc-linux-gnu.tar.bz2",
"url": "http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-i686-pc-linux-gnu.tar.bz2"
},
{
"size": "37630618",
"checksum": "SHA-256:bd8c37f6952a2130ac9ee32c53f6a660feb79bee8353c8e289eb60fdcefed91e",
"host": "x86_64-linux-gnu",
"archiveFileName": "avr-gcc-7.3.0-atmel3.6.1-arduino7-x86_64-pc-linux-gnu.tar.bz2",
"url": "http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-x86_64-pc-linux-gnu.tar.bz2"
}
]
},
The field name and version are respectively the name and version of the tool. Each tool is uniquely identified by
the triple (packager, name, version). packager (AKA "vendor") is defined by the name value of the tool's
package. There can be many different versions of the same tool available at the same time, for example:
- (
arduino,avr-gcc,5.4.0-atmel3.6.1-arduino2) - (
arduino,avr-gcc,7.3.0-atmel3.6.1-arduino5) - (
arduino,avr-gcc,7.3.0-atmel3.6.1-arduino7) - (
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:
- ARM Linux 32-bit (
arm-linux-gnueabihf), - ARM Linux 64-bit (
aarch64-linux-gnu), - macOS 64-bit (
x86_64-apple-darwin14), - Windows (
i686-mingw32), - Linux 32-bit (
i686-linux-gnu), - Linux 64-bit (
x86_64-linux-gnu)
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 this information is not used to select the toolchain during compilation. If you want this
specific version to be used, 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 archivearchiveFileName: 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 byteschecksum: the checksum of the archive, used to check if the file has been corrupted. The format isALGORITHM:CHECKSUM, currentlyMD5,SHA-1,SHA-256algorithm are supported, we recommendSHA-256. On *nix or macOS you can use the commandshasum -a 256 filenameto generate SHA-256 checksums. There are 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 GUIarchitecture: is the architecture of the platform (avr, sam, etc...). It must match the architecture of the core as explained in the Arduino platform specificationversion: the version of the platform.category: this field is reserved, a 3rd party core must set it toContributedhelp/online: is a URL that is displayed on the Arduino IDE's Boards Manager as an "Online Help" linkurl,archiveFileName,sizeandchecksum: metadata of the core archive file. The meaning is the same as for the TOOLSboards: the list of boards supported (note: just the names to display on the Arduino IDE and Arduino Pro IDE's Boards Manager GUI! the real boards definitions are insideboards.txtinside the core archive file)toolsDependencies: the tools needed by this core. They will be installed by Boards Manager along with the platform. 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, even if no platform of that package is installed.
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 (
.), parseversionas an integer and form a Version from that integer usingVersion.forIntegers - If there is one dot, split
versioninto two, parse each part as an integer, and form a Version from those integers usingVersion.forIntegers - Otherwise, simply parse
versioninto a Version usingVersion.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 empty.
Here is the Boards Manager entry created by the example: 
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 IDE 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 3rd party boards support urls.