Localization features provide a convenient way to retrieve strings in various languages, allowing you to easily support multiple languages within your application. Language strings are stored in files within the ./locales directory. Within this directory there should be a subdirectory for each language supported by the application:

│ main.go
│ home.yml
│ home.yml

The default language for your application is the first registered language.

app := iris.New()
// First parameter: Glob filpath patern,
// Second variadic parameter: Optional language tags,
// the first one is the default/fallback one.
app.I18n.Load("./locales/*/*", "en-US", "el-GR", "zh-CN")

Or if you load all languages by:

// Then set the default language using:

Load embedded locales

You may want to embed locales with a go-bindata tool within your application executable.

  1. install a go-bindata tool, e.g.

    $ go get -u

  2. embed local files to your application

    $ go-bindata -o locales.go ./locales/...

  3. use the LoadAssets method to initialize and load the languages

    ^ The AssetNames and Asset functions are generated by go-bindata

ap.I18n.LoadAssets(AssetNames, Asset, "en-US", "el-GR", "zh-CN")

Defining Translations

Locale files can be written at YAML(recommended), JSON, TOML or INI form.

Each file should contain keys. Keys can have sub-keys(we call them "sections") too.

Each key's value should be of form string or map containing by its translated text (or template) or/and its pluralized key-values.

Iris i18n module supports pluralization out-of-the-box, see below.

Fmt Style

hi: "Hi %s!"
ctx.Tr("Hi", "John")
// Outputs: Hi John!


hi: "Hi {{.Name}}!"
ctx.Tr("Hi", iris.Map{"Name": "John"})
// Outputs: Hi John!


Iris i18n supports plural variables. To define a per-locale variable you must define a new section of Vars key.

The acceptable keys for variables are:

  • one

  • "=x" where x is a number

  • "<x"

  • other

  • format


- Minutes:
one: "minute"
other: "minutes"
- Houses:
one: "house"
other: "houses"

Then, each message can use this variable, here's how:

# Using variables in raw string
YouLate: "You are %[1]d ${Minutes} late."
# [x] is the argument position,
# variables always have priority other fmt-style arguments,
# that's why we see [1] for houses and [2] for the string argument.
HouseCount: "%[2]s has %[1]d ${Houses}."
ctx.Tr("YouLate", 1)
// Outputs: You are 1 minute late.
ctx.Tr("YouLate", 10)
// Outputs: You are 10 minutes late.
ctx.Tr("HouseCount", 2, "John")
// Outputs: John has 2 houses.

You can select what message will be shown based on a given plural count.

Except variables, each message can also have its plural form too!

Acceptable keys:

  • zero

  • one

  • two

  • "=x"

  • "<x"

  • ">x"

  • other

Let's create a simple plural-featured message, it can use the Minutes variable we created above too.

"=3": "You have three days and %[2]d ${Minutes} off." # "FreeDay" 3, 15
one: "You have a day off." # "FreeDay", 1
other: "You have %[1]d free days." # "FreeDay", 5
ctx.Tr("FreeDay", 3, 15)
// Outputs: You have three days and 15 minutes off.
ctx.Tr("FreeDay", 1)
// Outputs: You have a day off.
ctx.Tr("FreeDay", 5)
// Outputs: You have 5 free days.

Let's continue with a bit more advanced example, using template text + functions + plural + variables.

- Houses:
one: "house"
other: "houses"
- Gender:
"=1": "She"
"=2": "He"
one: "${Gender} is awesome!"
other: "other (${Gender}) has %[3]d ${Houses}."
"=5": "{{call .InlineJoin .Names}} are awesome."
const (
female = iota + 1
ctx.Tr("VarTemplatePlural", iris.Map{
"PluralCount": 5,
"Names": []string{"John", "Peter"},
"InlineJoin": func(arr []string) string {
return strings.Join(arr, ", ")
// Outputs: John, Peter are awesome
ctx.Tr("VarTemplatePlural", 1, female)
// Outputs: She is awesome!
ctx.Tr("VarTemplatePlural", 2, female, 5)
// Outputs: other (She) has 5 houses.


If the key is not a reserved one (e.g. one, two...) then it acts as a sub section. The sections are separated by dot characters (.).

Message: "Welcome {{.Name}}"
ctx.Tr("Welcome.Message", iris.Map{"Name": "John"})
// Outputs: Welcome John

Determining The Current Locale

You may use the context.GetLocale method to determine the current locale or check if the locale is a given value:

func(ctx iris.Context) {
locale := ctx.GetLocale()
// [...]

The Locale interface looks like this.

// Locale is the interface which returns from a `Localizer.GetLocale` metod.
// It serves the transltions based on "key" or format. See `GetMessage`.
type Locale interface {
// Index returns the current locale index from the languages list.
Index() int
// Tag returns the full language Tag attached tothis Locale,
// it should be uniue across different Locales.
Tag() *language.Tag
// Language should return the exact languagecode of this `Locale`
//that the user provided on `New` function.
// Same as `Tag().String()` but it's static.
Language() string
// GetMessage should return translated text based n the given "key".
GetMessage(key string, args ...interface{}) string

Retrieving Translation

Use of context.Tr method as a shortcut to get a translated text for this request.

func(ctx iris.Context) {
text := ctx.Tr("hi", "name")
// [...]

Inside Views

func(ctx iris.Context) {
ctx.View("index.html", iris.Map{
"tr": ctx.Tr,