From LinuxReviews
Jump to navigationJump to search

Twinkle is a great free software VoIP softphone program for GNU/Linux. It supoprts the standard Session Initiation Protocol (SIP) protocol to talk to other SIP users and normal PSTN telephones through gateways and it had support for secure calls using the ZRTP and Secure Real-time Transport Protocol security protocols and MD5 digest authentication.

Twinkle 1.3.1.png
Twinkle Logo
Original author(s)Michel de Boer
Developer(s)Luboš Doležel
Stable release
Operating systemGNU

Development of Twinkle stalled sometime around 2010 and it's website expired and was bought by someone peddling adult entertainment products. It remained dead for years and years until it was ported to Qt5 in 2016.


  • SIP client
  • Instant messages with file attachments to other SIP softphones with support for SIMPLE (the text version of SIP)
  • Friends-list with online-status (if the contacts support online-status)

ZRTP Security

Twinkle supports ZRTP for secure calls to others capable of supporting this protocol. That is, in practice, nobody. While ZRTP is a great technology it isn't supported by any hardware phones and the vast majority of people you talk to will not support it.

Audio codecs

Twinkle supports all the audio codecs commonly used by SIP phones:

  • G.711 A-law (64 kbit/s payload, 8 kHz sampling rate)
  • G.711 μ-law (64 kbit/s payload, 8 kHz sampling rate)
  • G.726 (16, 24, 32 or 40 kbit/s payload, 8 kHz sampling rate)
  • GSM (13 kbit/s payload, 8 kHz sampling rate)
  • iLBC (13.3 or 15.2 kbit/s payload, 8 kHz sampling rate)
  • Speex narrow band (15.2 kbit/s payload, 8 kHz sampling rate)
  • Speex wide band (28 kbit/s payload, 16 kHz sampling rate)
  • Speex ultra wide band (36 kbit/s payload, 32 kHz sampling rate)

Source code

You should always make sure that you have full access to the source code when using cryptographic software. Twinkle respects your rights and allows you to verify that the software is safe to use.


The original projects website is now some kind of erotic product review site. The modern port to Qt5 can be found at