FT8 - WSJT-X

WSJT-X implements communication protocols or "modes" called FST4, FST4W, FT4, FT8, JT4, JT9, JT65, Q65, MSK144, and WSPR, as well as one called Echo for detecting and measuring your own radio signals reflected from the Moon.  These modes were designed for making reliable, confirmed QSOs under extreme weak-signal conditions.
JT4, JT9, and JT65 use nearly identical message structure and source encoding (the efficient compression of standard messages used for minimal QSOs). They use timed 60-second T/R sequences synchronized with UTC.  JT4 and JT65 were designed for EME ("moonbounce") on the VHF/UHF/microwave bands.  JT9 is optimized for the MF and HF bands.  It  is about 2 dB more sensitive than JT65 while using less than 10% of the bandwidth.  Q65 offers submodes with a wide range of T/R sequence lengths and tone spacings; it is highly recommended for EME, ionospheric scatter, and other weak signal work on VHF, UHF, and microwave bands.
FT4 and FT8 are operationally similar but use T/R cycles only 7.5 and  15 s long, respectively.  MSK144 is designed for Meteor Scatter on the VHF bands.  These modes offer enhanced message formats with support for nonstandard callsigns and some popular contests.
FST4 and FST4W are designed particularly for the LF and MF bands. On these bands their fundamental sensitivities are better than other WSJT-X modes with the same sequence lengths, approaching the theoretical limits for their rates of information throughput. FST4 is optimized for two-way QSOs, while FST4W is for quasi-beacon transmissions of WSPR-style messages. FST4 and FST4W do not require the strict, independent time synchronization and phase locking of modes like EbNaut.
WSPR mode implements a protocol designed for probing potential propagation paths with low-power transmissions.
WSPR is fully implemented within WSJT-X, including programmable "band-hopping".

PSK Automatic Propagation Reporter

PSK reporter started out as a project to automatically gather reception records of digimode activity and then make those records available in near realtime to interested parties — typically the amateur who initiated the communication. The way that it works is that many amateurs will run a client that will monitor received traffic for callsigns (the pattern 'de callsign callsign') and, when seen, will report this fact. This is of interest to the amateur who transmitted adn they will be able to see where their signal was received. The pattern chosen is typically part of a standard CQ call. The duplicate check is to make sure that the callsign is not corrupted. The rules for protocols like FT8 are different as the callsigns are protected by error correction. You do still need to call CQ in order for your signal to be reported.