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Technical specifications and data protection

What is Wordfast Server?

Wordfast Server (WFS) is a translation memory (TM) and terminology server.


Supported platforms

WFS runs as a Windows application on any Windows machine that is connected to the Internet. Those include Windows 2000™, Windows XP™, Windows Server™ 2000–2022, Windows Vista™, Windows 7™, and Windows 8™, or Windows 10.x™ and later versions.


Required environment

WFS does not require any third-party database system – it uses its own proprietary database and indexing system. Thus, it is not necessary to own or enable Windows database services or DBMSes like Microsoft SQL Server™, ODBC, Oracle™, etc. For optimal performance of WFS, you should minimize the number of third-party applications and services installed and running on that workstation.


Data protection & GDPR compliance

As of March 2019, WFS implements state-of-the-art measures to ensure data protection pursuant to, or exceeding, European GDPR standards. Three levels of protection are implemented.

1. Database encryption

Translation memories and glossaries, which are the databases used by WFS, can be encrypted with military-strength encryption. To do so, in the TMs or Glossaries panes in WFS, right-click a particular item, then under Convert format to, choose Encrypted. The reverse operation (decryption) follows the same path: right-click an item (TM or glossary), then under Convert format to, choose another non-encrypted format, like Unicode.

2. User interface lock

To protect the database from hackers who may have gained control of the host machine, WFS’s User Interface (UI) can be locked. To do so, in Setup > Users, specify a password. You can set a recovery question and answer as a password recovery measure.

Then in Setup > Activity, check Lock interface, then set an inactivity time (in seconds) after which the UI will lock itself. Note that double-clicking the empty space to the right of the Setup tab icon will lock the UI immediately, if you need.

3. Settings encryption

WFS keeps settings in .stats files, named after WfServer.exe’s file name, for example, WfServer.stats. The data in those setting files is in clear format, except passwords, which are encrypted. As a consequence: if you lose or forget a password, it cannot be recovered, not even by Wordfast LLC personnel. You can further enhance security by encrypting .stats files, keeping session login names, file paths and names, etc. from prying eyes. To do so, check the Encrypted checkbox in the Setup > Setup tab. Note that even if you don't encrypt those files, the passwords they contain are protected anyway. Setup encryption protects all sensitive information such as account names, path and file names, traffic, activity, etc.

! Important note.

To maximize protection, all security measures described above are enforced for a session of WFS running in one particular context. "Context" is dependent on your local workstation’s hardware and software characteristics: motherboard, CPU, BIOS, Operating System version, local machine name, and also path and name to the WFS application, and to all encrypted files (TMs, glossaries, settings aka ".stats" files).

As a consequence, any change of the above characteristics (even just moving files or the WFS application) will alter the context and invalidate encrypted files and/or WFS’ setup.

Wordfast LLC’s personnel cannot help if you have lost passwords, or if the context has changed and passwords were lost.

Those conditions are drastic. They are enforced to maximize resilience against hostile attacks. Anything less would endanger your data.

In the event hackers clone & steal your entire hard disk to boot it elsewhere (therefore including OS, applications, setups, and data), they will not be able to run WFS and exploit your data: WFS will not work if it senses that the underlying hardware has changed.

When using encryption, refrain from letting the Operating System perform automatic updates (most servers have that option disabled). Do not upgrade or change physical characteristics of the local workstation while data is encrypted without following the simple migration procedure below.

Migration or change of context procedure

Follow this procedure to migrate encrypted database files, or a WFS application, with an encrypted setup. Migration means moving to another folder or computer in the same PC, or modify (even just update) the system's software or hardware, or migrate to a new PC:

  • Optional: decrypt TMs and glossaries (right-click TMs or glossaries, Convert format to > Unicode), close WFS, back up the data, and keep it in a safe storage. This is recommended. However, note that it is possible to move encrypted data to the new context.
  • Compulsory: in the existing context, before migration, in WFS’s Setup > Setup pane, uncheck Encrypted, then close WFS. This will rewrite the .stats file in clear (uncrypted) format. This must be done before migration. It is useless moving an encrypted .stats file. We recommend unchecking Lock interface just to keep things simple, in Setup > Activity during migration.

Now WfServer.exe can safely be restarted in the new context. When restarting WfServer.exe in a new context, if WFS senses encrypted data, you will be prompted for the admin password that was used in the previous context so that the encrypted files can be exploited in the new context. However, note that the .stats file in the new context must be copied in clear, non-encrypted format.


Client-server communication channel

WFS uses TCP-IP to communicate with clients such as Wordfast Pro, Wordfast Classic, or Wordfast Anywhere. It uses its own protocol on top of TCP-IP, as well as its own military-strength encryption method. Thus, all WFS needs is a valid Windows socket. IIS or other services do not need to be activated. Another communication channel uses an easier HTTP protocol through a small application (WfServerRelay). This manual’s Appendix 2 describes a REST API which allows developers to connect their applications to Wordfast Server in literally less than an hour.


Physical requirements

WFS only needs a basic, Windows platform with an internet connection to run.

Hard disk: A minimum of 10 MB is needed to install and run the application. For the database (TMs and glossaries), reserve three times the expected bare database size to accommodate indexes and temporary files. RAM: Over 2 GB. Processor: Any processor can be used.


Server capacity

One instance of WFS can exploit a database of up to 10,000 Translation Memories (with any number of different language pairs), totalling up to 1,000,000,000 Translation Units (TU), and serving up to 5,000 clients.

A collection of TMs is a database, a TM is a table within the database, and a TU is a record within the table.

Most clients will start with one server serving all languages simultaneously, and will probably never outgrow WFS’ capacity. However, it is possible to split the load among as many servers as there are language pairs (one TM supports only one language pair), or even one server per TM, so that stellar scalability is achieved.


Database format

WFS’ native TM format is the Wordfast TM format, which is a tab-delimited text file, as described in the Wordfast Classic Reference Manual ("TM format" chapter, or in Appendix 4 in the WFS manual). It’s the simplest of all formats—it can be opened with text editors, like Notepad, or unicode-compliant word processors, as well as with Excel. Wordfast TMs can be regular ANSI (8-bit) text, or Unicode UTF-16 (both little-endian and big-endian). WFS can import TUs from TMX TMs (all levels of TMX), and from Wordfast TMs. The Wordfast TM format is the most compact and reliable TM format in the industry. Note that the Wordfast TM format does not systematically store text formatting information (inline codes) per se, because they are known to bloat and choke TMs. It does record, however, placeholders for all third-party “tags”, which are meant to preserve formatting when the user wants it to. In short, the Wordfast format stores formatting information using a symbolic method.



The WFS database is a collection of discrete TXT files (one TXT file per TM and one TXT file per glossary), plus one single configuration file with a .stats extension. All other files, such as indexes and temporary files can be recreated as needed by WFS.

Backing up simply means backing up TMs, glossaries, and the single .stats file. Any standard method can be used, including mirroring, replication, RAID strategies, etc. The only requirement is that the backup method accommodates “live” files. If that is not the case, the server should be stopped before files are backed up. Most modern backup utilities can back up live files.