Goslate: Free Google Translate API


Google has updated its translation service recently with a ticket mechanism to prevent simple crawler program like goslate from accessing. Though a more sophisticated crawler may still work technically, however it would have crossed the fine line between using the service and breaking the service. goslate will not be updated to break google’s ticket mechanism. Free lunch is over. Thanks for using.

goslate provides you free python API to google translation service by querying google translation website.

It is:

  • Free: get translation through public google web site without fee
  • Fast: batch, cache and concurrently fetch
  • Simple: single file module, just Goslate().translate('Hi!', 'zh')

Simple Usage

The basic usage is simple:

>>> import goslate
>>> gs = goslate.Goslate()
>>> print(gs.translate('hello world', 'de'))
hallo welt


goslate support both Python2 and Python3. You could install it via:

$ pip install goslate

or just download latest goslate.py directly and use

futures pacakge is optional but recommended to install for best performance in large text translation task.

Proxy Support

Proxy support could be added as following:

import urllib2
import goslate

proxy_handler = urllib2.ProxyHandler({"http" : "http://proxy-domain.name:8080"})
proxy_opener = urllib2.build_opener(urllib2.HTTPHandler(proxy_handler),

gs_with_proxy = goslate.Goslate(opener=proxy_opener)
translation = gs_with_proxy.translate("hello world", "de")


Romanization or latinization (or romanisation, latinisation), in linguistics, is the conversion of writing from a different writing system to the Roman (Latin) script, or a system for doing so.

For example, pinyin is the default romanlization method for Chinese language.

You could get translation in romanlized writing as following:

>>> import goslate
>>> roman_gs = goslate.Goslate(writing=goslate.WRITING_ROMAN)
>>> print(roman_gs.translate('China', 'zh'))

You could also get translation in both native writing system and ramon writing system

>>> import goslate
>>> gs = goslate.Goslate(writing=goslate.WRITING_NATIVE_AND_ROMAN)
>>> gs.translate('China', 'zh')
('中国', 'Zhōngguó')

You could see the result will be a tuple in this case: (Translation-in-Native-Writing, Translation-in-Roman-Writing)

Language Detection

Sometimes all you need is just find out which language the text is:

>>> import golsate
>>> gs = goslate.Goslate()
>>> language_id = gs.detect('hallo welt')
>>> language_id
>>> gs.get_languages()[language_id]

Concurrent Querying

It is not necessary to roll your own multi-thread solution to speed up massive translation. Goslate already done it for you. It utilizes concurrent.futures for concurent querying. The max worker number is 120 by default.

The worker number could be changed as following:

>>> import golsate
>>> import concurrent.futures
>>> executor = concurrent.futures.ThreadPoolExecutor(max_workers=200)
>>> gs = goslate.Goslate(executor=executor)
>>> it = gs.translate(['text1', 'text2', 'text3'])
>>> list(it)
['tranlation1', 'translation2', 'translation3']

It is adviced to install concurrent.futures backport lib in python2.7 (python3 has it by default) to enable concurrent querying.

The input could be list, tuple or any iterater, even the file object which iterate line by line

>>> translated_lines = gs.translate(open('readme.txt'))
>>> translation = '\n'.join(translated_lines)

Do not worry about short texts will increase the query time. Internally, goslate will join small text into one big text to reduce the unnecessary query round trips.

Batch Translation

Google translation does not support very long text, goslate bypass this limitation by split the long text internally before send to Google and join the mutiple results into one translation text to the end user.

>>> import golsate
>>> with open('the game of thrones.txt', 'r') as f:
>>>     novel_text = f.read()
>>> gs = goslate.Goslate()
>>> gs.translate(novel_text)

Performance Consideration

Goslate use batch and concurrent fetch aggresivelly to achieve maximized translation speed internally.

All you need to do is reducing API calling times by utilize batch tranlation and concurrent querying.

For example, say if you want to translate 3 big text files. Instead of manually translate them one by one, line by line:

import golsate

big_files = ['a.txt', 'b.txt', 'c.txt']
gs = goslate.Goslate()

translation = []
for big_file in big_files:
    with open(big_file, 'r') as f:
        translated_lines = []
        for line in f:
            translated_line = gs.translate(line)


It is better to leave them to Goslate totally. The following code is not only simpler but also much faster (+100x) :

import golsate

big_files = ['a.txt', 'b.txt', 'c.txt']
gs = goslate.Goslate()

translation_iter = gs.translate(open(big_file, 'r').read() for big_file in big_files)
translation = list(translation_iter)

Internally, goslate will first adjust the text to make them not so big that do not fit Google query API nor so small that increase the total HTTP querying times. Then it will use concurrent query to speed thing even further.

Lookup Details in Dictionary

If you want detail dictionary explaination for a single word/phrase, you could

>>> import goslate
>>> gs = goslate.Goslate()
>>> gs.lookup_dictionary('sun', 'de')
[[['Sonne', 'sun', 0]],
   [['Sonne', ['sun', 'Sun', 'Sol'], 0.44374731, 'die']],
   ['der Sonne aussetzen'],
   [['der Sonne aussetzen', ['sun'], 1.1544633e-06]],
 [['en'], [0.9447732]]]

There are 2 limitaion for this API:

  • The result is a complex list structure which you have to parse for your own usage
  • The input must be a single word/phase, batch translation and concurrent querying are not supported

Query Error

If you get HTTP 5xx error, it is probably because google has banned your client IP address from transation querying.

You could verify it by access google translation service in browser manully.

You could try the following to overcome this issue:

  • query through a HTTP/SOCK5 proxy, see Proxy Support
  • using another google domain for translation: gs = Goslate(service_urls=['http://translate.google.de'])
  • wait for 3 seconds before issue another querying

Command Line Interface

goslate.py is also a command line tool which you could use directly

  • Translate stdin input into Chinese in GBK encoding

    $ echo "hello world" | goslate.py -t zh-CN -o gbk
  • Translate 2 text files into Chinese, output to UTF-8 file

    $ goslate.py -t zh-CN -o utf-8 source/1.txt "source 2.txt" > output.txt

use --help for detail usage

$ goslate.py -h

What’s New


  • Add new API Goslate.lookup_dictionary() to get detail information for a single word/phrase, thanks for Adam’s suggestion
  • Improve document with more user scenario and performance consideration


  • [fix bug] update to adapt latest google translation service changes


  • [fix bug] fix compatible issue with latest google translation service json format changes
  • [fix bug] unit test failure


  • [new feature] Translation in roman writing system (romanlization), thanks for Javier del Alamo’s contribution.
  • [new feature] Customizable service URL. you could provide multiple google translation service URLs for better concurrency performance
  • [new option] roman writing translation option for CLI
  • [fix bug] Google translation may change normal space to no-break space
  • [fix bug] Google web API changed for getting supported language list


Goslate: Free Google Translate API

exception goslate.Error

Error type

class goslate.Goslate(writing=(u'trans', ), opener=None, retry_times=4, executor=None, timeout=4, service_urls=(u'http://translate.google.com', ), debug=False)

All goslate API lives in this class

You have to first create an instance of Goslate to use this API

  • writing

    The translation writing system. Currently 3 values are valid

  • opener (urllib2.OpenerDirector) – The url opener to be used for HTTP/HTTPS query. If not provide, a default opener will be used. For proxy support you should provide an opener with ProxyHandler
  • retry_times (int) – how many times to retry when connection reset error occured. Default to 4
  • timeout (int/float) – HTTP request timeout in seconds
  • debug (bool) – Turn on/off the debug output
  • service_urls (single string or a sequence of strings) – google translate url list. URLs will be used randomly for better concurrent performance. For example ['http://translate.google.com', 'http://translate.google.de']
  • executor (futures.ThreadPoolExecutor) – the multi thread executor for handling batch input, default to a global futures.ThreadPoolExecutor instance with 120 max thead workers if futures is avalible. Set to None to disable multi thread support


multi thread worker relys on futures, if it is not avalible, goslate will work under single thread mode

>>> import goslate
>>> # Create a Goslate instance first
>>> gs = goslate.Goslate()
>>> # You could get all supported language list through get_languages
>>> languages = gs.get_languages()
>>> print(languages['en'])
>>> # Tranlate English into German
>>> print(gs.translate('Hello', 'de'))
>>> # Detect the language of the text
>>> print(gs.detect('some English words'))
>>> # Get goslate object dedicated for romanlized translation (romanlization)
>>> gs_roman = goslate.Goslate(WRITING_ROMAN)
>>> print(gs_roman.translate('hello', 'zh'))
Nín hǎo

Detect language of the input text


  • Input all source strings at once. Goslate will detect concurrently for maximize speed.
  • futures is required for best performance.
  • It returns generator on batch input in order to better fit pipeline architecture.
Parameters:text (UTF-8 str; unicode; sequence of string) – The source text(s) whose language you want to identify. Batch detection is supported via sequence input
Returns:the language code(s)
  • unicode: on single string input
  • generator of unicode: on batch input of string sequence
Raises:Error if parameter type or value is not valid


>>> gs = Goslate()
>>> print(gs.detect('hello world'))
>>> for i in gs.detect([u'hello', 'Hallo']):
...     print(i)

Discover supported languages

It returns iso639-1 language codes for supported languages for translation. Some language codes also include a country code, like zh-CN or zh-TW.


It only queries Google once for the first time and use cached result afterwards

Returns:a dict of all supported language code and language name mapping {'language-code', 'Language name'}
>>> languages = Goslate().get_languages()
>>> assert 'zh' in languages
>>> print(languages['zh'])
lookup_dictionary(text, target_language, source_language=u'auto', examples=False, etymology=False, pronunciation=False, related_words=False, synonyms=False, antonyms=False, output_language=None)

Lookup detail meaning for single word/phrase


  • Do not input sequence of texts
  • text (UTF-8 str) – The source word/phrase(s) you want to lookup.
  • target_language (str; unicode) – The language to translate the source text into. The value should be one of the language codes listed in get_languages()
  • source_language (str; unicode) – The language of the source text. The value should be one of the language codes listed in get_languages(). If a language is not specified, the system will attempt to identify the source language automatically.
  • examples – include example sentences or not
  • pronunciation – include pronunciation in roman writing or not
  • related_words – include related words or not
  • output_language – the dictionary’s own language, default to English.

a complex list structure contains multiple translation meanings for this word/phrase and detail explaination.

translate(text, target_language, source_language=u'auto')

Translate text from source language to target language


  • Input all source strings at once. Goslate will batch and fetch concurrently for maximize speed.
  • futures is required for best performance.
  • It returns generator on batch input in order to better fit pipeline architecture
  • text (UTF-8 str; unicode; string sequence (list, tuple, iterator, generator)) – The source text(s) to be translated. Batch translation is supported via sequence input
  • target_language (str; unicode) – The language to translate the source text into. The value should be one of the language codes listed in get_languages()
  • source_language (str; unicode) – The language of the source text. The value should be one of the language codes listed in get_languages(). If a language is not specified, the system will attempt to identify the source language automatically.

the translated text(s)

  • unicode: on single string input
  • generator of unicode: on batch input of string sequence
  • tuple: if WRITING_NATIVE_AND_ROMAN is specified, it will return tuple/generator for tuple (u”native”, u”roman format”)

  • Error (‘invalid target language’) if target language is not set
  • Error (‘input too large’) if input a single large word without any punctuation or space in between
>>> gs = Goslate()
>>> print(gs.translate('Hello World', 'de'))
Hallo Welt
>>> for i in gs.translate(['good', u'morning'], 'de'):
...     print(i)

To output romanlized translation

>>> gs_roman = Goslate(WRITING_ROMAN)
>>> print(gs_roman.translate('Hello', 'zh'))
Nín hǎo
goslate.WRITING_NATIVE = (u'trans',)

native target language writing system

goslate.WRITING_NATIVE_AND_ROMAN = (u'trans', u'translit')

both native and roman writing. The output will be a tuple

goslate.WRITING_ROMAN = (u'translit',)

romanlized writing system. only valid for some langauges, otherwise it outputs empty string