About A.nnotate

A.nnotate is the flagship product of Textensor Limited which was incorporated in Edinburgh, Scotland in 2005. The founders had been working for several years on technologies for information capture, storage and reuse in biosciences. Their vision led them to focus on ease of use and universal availability for the core concepts of annotation and collaboration, and they are proud to be able to make these publicly available in A.nnotate.

In 2014 they launched Annotate.co, a major new distributed cloud service across four continents (Europe, USA, Canada, Australia and Asia). The new Annotate.co service enables group collaboration and discussion of PDFs, with many new features including workspaces and fine-grained user permissions. We will continue the current a.nnotate.com service for our many customers who rely on it, but we expect new users will prefer to use the annotate.co service.


Robert Cannon focuses on user interface engineering, marketing and user support. He has a PhD in applied mathematics from Cambridge University and more than 20 years experience in software design and development.

Fred Howell focuses on server engineering, installation, sales and support. He has a PhD in computer science from Edinburgh University and more than 20 years experience in academic and commercial software development.

Today A.nnotate is used online by thousands of individuals and groups who need to store or share comments on documents, web pages or images. Standalone servers are in use in universities, SMEs, blue chip companies and the public sector. A.nnotate technology is increasingly chosen by developers to add annotation capabilities to their own high-value web applications thanks to its flexible licensing, ease of use, and outstanding technical support.

Textensor Limited is wholly owned by the founders and has no debts or investment. It is committed to sustainable organic growth by reinvesting profits from the sale of products and services with additional revenue from customization and consultancy work.

Product history

The founders, Fred Howell and Robert Cannon each have more than ten years research experience in physics, neuroscience and computing. Before starting Textensor, they had been working on problems of management and reuse of biomedical data. The key problem was with the large number of studies that yield heterogeneous information including papers and other textual material that does not fit well in conventional database models. Efforts to shoehorn information expressed in documents into structured or semi-structured databases have had mixed results and there has been very little progress in replacing text as the preferred way to represent complex information.

Realizing that databases could add to but were very unlikely to supplant written text, the developers of A.nnotate started from the other end. They began working on ways to let authors enhance texts with a structured annotation layer that would enable some of the results to be processed automatically while keeping references back to locations in the original text for each assertion. Sidestepping efforts towards automated natural language processing they focussed instead on how the author interacts with the system, with the aim of enabling authors to add structure and value, rather than just mechanically re-expressing what was already there. As their work shifted from pure research to more practical prototypes, they founded Textensor (Text + (ext)ensor) with an R&D grant from the Scottish government to pursue these ideas. The first prototype is described in a white paper: Enhancing documents with annotations and machine-readable structured information using Notate.

The most enthusiastic user response to the early software was not for the sophisticated structured content features, but for the core capabilities of tagging, annotating and collaborating on text documents. The focus therefore shifted to rendering and annotating a wider range of document types including PDF and Word as smoothly and easily as possible. This led directly to the hosted solutions at A.nnotate.com launched in January 2008 and was soon followed by standalone server products for Linux and Windows. A major upgrade at the end of 2008 saw the addition of image annotation capabilities, comprehensive document storage and management, and an extensive API for the growing number of customers who combine A.nnotate with their own web aplications.

The company's origins in university research are reflected in the substantial discounts and flexible licensing conditions offered for servers to be used in education or publicly funded research.