Online (web-based) software can:

• enable large numbers of people to interact with databases and models;
• allow users in remote locations to access models and data that are frequently updated; and
• demonstrate key principles that underlie more detailed mathematical models.

In particular, openness and transparency are vital elements of environmental and energy decision making, in view of the wide range and distribution of stakeholders. However, the data, modelling and reasoning behind such decisions are often the preserve of experts and thus difficult to scrutinise. Quintessa's online modelling initiative aims to democratise quantitative aspects of decision-making.

Historically, Quintessa have created web-based applications for the Japan Atomic Energy Agency, and the UK Atomic Energy Authority, the former being a wiki-style system (PARIZADE) for managing knowledge associated with radioactive waste disposal, and the latter being a parameter database of version-controlled performance assessment data, with review and approval controls. Quintessa's longest standing and most widely used web-based application is the CO2 FEP database, which is an online database of Features, Events and Processes of relevance to the long-term integrity of carbon dioxide storage in geological formations to mitigate climate change.

Quintessa’s own internal Information Systems (QIS), which are used for project management and associated processes, timesheets, time planning, staff whereabouts and company contacts are also web-based and developed in-house.

Quintessa has developed a web-based database-driven application for the Nuclear Energy Agency (NEA) to manage a database of Features, Events and Processes (FEP) relevant to the long-term safety of geological disposal facilities for radioactive waste (NEA FEP Database).

Software development at Quintessa is undertaken under a Quality Management System that is certified to be in accordance with the requirements of ISO 9001:2015 and the TickITplus standard for software development.