Lingo4G editions are based on the total size of the indexed documents and the number of documents analyzed in one request.

Small Server

For simple research or as an alternative to Lingo3G

  • Deployed on one or more of your servers

Medium Server

Good for the majority of typical data sets

  • Deployed on one or more of your servers

Large Server

For complex research and large data sets

  • Deployed on one or more of your servers

Unlimited Server

For massive data sets

  • unlimited*
    indexed docs
    Required for PubMed Open Access or US patents data set.
  • unlimited*
    docs per request
  • Deployed on one or more of your servers


For redistribution as part of your software

  • unlimited*
    indexed docs
  • unlimited*
    docs per request
  • Embedded and sold as part of your software
Indexed docs: total size of content in your collection.
Docs per request: number of documents analyzed at a time.
*) Limited only by CPU, memory and disk capacity.

Included in all editions

Topic discovery

Near-real time extraction of clearly-labelled themes present in your documents.

Document clustering

Grouping content-wise similar documents into non-overlapping clusters.

Document embedding

Arranging documents into 2d maps with textually-similar docs grouped together.


Calling Lingo4G from any programming language, Java and Node.js examples provided.

Command line interface

CLI application for indexing and analyzing your content in Lingo4G.

Lingo4G Explorer

Web application for experimenting with and tuning Lingo4G processing.

FoamTree visualization

When used as part of Lingo4G Explorer. (Use outside of Explorer requires a license.)

dotAtlas visualization

When used as part of Lingo4G Explorer. (For use outside of Explorer, contact us to get the pre-release version.)

Licensing terms

Licensing period

One-year and perpetual licenses are available for server editions. One-year license will stop working after 12 months. To continue using the software, you will need to purchase another one-year or perpetual license. Perpetual licenses will work indefinitely.

Support and updates

All server licenses come with 12 months of software maintenance, which includes support, minor and major product updates. Beyond this initial 12 month period, at any time, you may add further 12 months of software maintenance to your license at 50% of the initial purchase price.

All licenses come with several hours of free consulting, usually spent on integration with your existing software and clustering quality tuning.

All licenses allow using Lingo4G internally for the evaluation, development, testing and tuning purposes.


Please contact us for further licensing and pricing information.

Licensing upgrades

Upgrades from one-year to perpetual and from a lower to a higher edition (e.g. from Medium to Large) are possible within the validity period of the original license.

Volume and OEM licensing

For non-typical scenarios, such as large-scale server deployments or redistribution of Lingo4G as part of other software, licensing terms are negotiated separately to best match the customer's sales and distribution models. If you think you will need such a license, please get in touch to discuss the details.

Lingo3G license trade-in

Holders of perpetual Lingo3G licenses can "trade in" their Lingo3G license to receive a Lingo4G license. We will count the initial purchase price (but not the maintenance extension fees) paid for Lingo3G towards the price of the Lingo4G license you wish to switch to. Once you trade-in your Lingo3G license, you will not be allowed to use Lingo3G with that license any more. To cover the Lingo3G to Lingo4G transition period, we'll issue long-term Lingo4G evaluation licenses.

Questions & Answers

Are there any subscription fees?

No. Both one-year and perpetual server licenses are available for a one-time licensing fee.

How many collections can I process on one server?

There are no restrictions on the number of Lingo4G instances running on one physical or virtual server. The only limit may be the capacity of the server, including RAM size, disk space and the number of CPUs.

Can I get a trial license?

Absolutely! Please get in touch for a free evaluation package.

I have a Lingo3G license, will I receive Lingo4G as an upgrade?

No. Lingo3G and Lingo4G are two separate products we intend to offer and maintain independently. Lingo3G will remain an engine for real-time clustering of small and medium collections, while Lingo4G will address clustering of large data sets. Therefore, Lingo4G is not an upgrade to Lingo3G, but a complementary offering.

Having said that, if you would like to switch from Lingo3G to Lingo4G, we offer a license trade-in option and count the initial Lingo3G license purchase fee towards the Lingo4G license fee.

What kind of limits can my Lingo4G license include?

Depending on your Lingo4G edition, your license file may include two limits:

  • Maximum total size of indexed documents, defined by the max-indexed-content-length attribute of your license file. The limit restricts the maximum total size of the text indexed for the purposes of Lingo4G analysis. Text stored in the index only for literal retrieval is not counted towards the limit.

  • Maximum number of documents analyzed in one request, defined by the max-documents-in-scope attribute of your license file. The limit defines the maximum size of the subset of your collection Lingo4G will analyze at a time. If the number of documents matching the subset definition query exceeds the limit, Lingo4G will ignore the lowest-scoring documents.

    For example, the Medium Server edition will allow you to index all 240k (spanning about 3GB) questions from and will cluster or extract topics for at most 50k questions at a time. If you request processing of a subset larger than 50k questions, Lingo4G will analyze the top 50k questions matching the subset definition query.

The above limits are enforced for each Lingo4G instance separately.

Is the total number of documents in the index limited?

No. Regardless of your Lingo4G edition, there will be no license-enforced limits on the total number of documents in Lingo4G index.

Take Lingo4G for a spin

Use fully-functional Unlimited Server version for 2 months free of charge.

Get a trial