A plain guide to IBM DOORS, the requirements management software used on large systems engineering programmes: what the acronym means, how DOORS Classic differs from DOORS Next, and how DOORS organises requirements. Then Reqi, an alternative built on INCOSE principles and priced per project with unlimited users, so you can judge whether it fits the programme you are running.
Looking for DOORS itself? You want IBM's own product page. This page is about a different tool, from a different vendor, and we would rather you got where you were going.
IBM DOORS is requirements management software for capturing, tracing, analysing and managing requirements on complex engineering programmes. IBM describes it as used by teams on complex, high-compliance systems engineering programmes across all industrial sectors for several decades. That is a fair description and we are not going to argue with it.
DOORS is an acronym for Dynamic Object-Oriented Requirements System. The name reflects its data model: requirements are stored as objects inside modules, and the links between objects are what give you traceability. Wikipedia's history of the product covers the origins in more detail.
The same product has carried several names, which is why searches for it are so varied. It was developed by Quality Systems and Software, sold by Telelogic as Telelogic DOORS, became IBM Rational DOORS after IBM acquired Telelogic in 2008, and is now sold as IBM Engineering Requirements Management DOORS. Today it comes in two forms, and it is worth knowing which one a colleague means when they say "DOORS".
If DOORS is embedded in your organisation and working, this page is probably not for you.
Everything above is taken from IBM's own documentation and linked so you can check it. We make no claim here about what DOORS costs, how it performs, or how it compares on features, because we cannot source those statements. Ask IBM.
If you are new to DOORS, or evaluating it against other requirements management tools, these are the concepts the IBM DOORS documentation is built around. This is orientation, not a DOORS tutorial; IBM's documentation is the place for step-by-step instructions.
Requirements live in formal modules. Each row in a module is an object, which carries the requirement text plus attributes such as identifier, status and priority. A project is a set of modules.
Objects are linked across modules, for example from a system requirement down to the subsystem requirements that satisfy it. Following the links in either direction is how DOORS requirements traceability works.
A baseline freezes a module at a point in time so that a review or a contract milestone can be referred back to. Views filter and sort a module for a particular audience.
DOORS eXtension Language is the scripting language used to automate and extend DOORS Classic. Established DXL libraries are a large part of the switching cost for organisations that have used DOORS for years.
If you know DOORS, this is the quickest way to understand how Reqi is organised.
| In DOORS | In Reqi |
|---|---|
| Project of formal modules | A project with a single requirements register, viewed as a table, a network diagram or a tree |
| Object with attributes | A requirement with identifier, text, rationale, status, phase and acceptance criteria |
| Links between objects | Parent and derived requirements, plus allocation of each requirement to systems in the system breakdown structure |
| Baselines | Review and agreed states on allocations, with acceptance and verification evidence recorded against each requirement |
| DXL scripts | REX, the AI assistant, for quality checks, extraction from documents, allocation and derivation, with no scripting |
| Per-seat client licences | Per project, unlimited users, in a browser |
A requirements management platform for systems engineering, built for project teams, systems engineers and asset owners in regulated industries. It runs in a browser on Azure, with ISO 27001 and SOC 2 compliance and an Australian data centre. The detail is on our data security page.
$190 per month plus GST covers a project, and every plan carries unlimited users. Bringing a contractor or a supplier into the programme does not change the invoice.
REX scores requirements against the INCOSE 42-Point Guide and shows what is wrong and how to fix it. It is free, needs no sign-up, and reads PDFs to pull a structured requirement list out of a contract or specification.
Give Reqi a top-level need and it proposes the system breakdown structure, suggests boundaries and allocates managers and reviewers, then flows requirements down the hierarchy level by level.
Internal teams, contractors and suppliers see the same real-time information, with responsibilities tracked and dependencies visualised across organisations.
$190 per month, plus GST
Per project, for one to five projects. Unlimited users on every plan.
A single project is free for three months, up to 500 requirements, with unlimited users and no card. Programmes above five projects are quoted. Full detail on the pricing section, and a fuller description of the platform on our requirements management software page.
DOORS Classic can export a module to a spreadsheet, and Reqi imports requirements from Excel and CSV files. In practice the move is: export the module from DOORS with the attributes you want to keep, tidy the columns in Excel, then import into a Reqi project where identifiers, text, rationale and status map onto the register. Word documents and PDF specifications can be imported too, with REX extracting the requirement list. ReqIF import is not currently supported, so if your DOORS data is only available as ReqIF, talk to us before you start.
Links between objects do not survive a spreadsheet export as links. Rebuild the hierarchy in Reqi by setting parent requirements and allocating to systems, which REX can propose for review.
We are not going to pretend this is a close call in every case. DOORS has decades of deployment behind it on very large programmes, and organisations with DXL scripts, established integrations and trained teams have a real switching cost that no feature list offsets.
Reqi is worth a look when the people who need to see the requirements sit in different organisations, when per-seat licensing is what stops you inviting them, or when the programme is small enough that a three-month free project will tell you more than a procurement exercise will. New to the discipline rather than migrating? Start with our introduction to DOORS for beginners or the requirements engineering framework.
Dynamic Object-Oriented Requirements System. The name describes the data model: requirements as objects in modules, linked to each other for traceability.
DOORS Classic is the original product with a Windows client. DOORS Next, formerly DOORS Next Generation, runs on the Jazz platform with a web client. They are separate products with separate data stores.
Yes. Rational DOORS was the product's name after IBM's 2008 acquisition of Telelogic. It is now sold as IBM Engineering Requirements Management DOORS.
IBM does not publish a price and we will not guess at one. Ask IBM. Reqi is $190 per month plus GST per project, with unlimited users, and a single project is free for three months.
Reqi's free project runs for three months with up to 500 requirements and unlimited users, with no card. REX, the requirement quality checker, is free with no sign-up at all.
Yes, via a spreadsheet export from DOORS and Reqi's Excel or CSV import. See the migration notes above.
Three months free, 500 requirements, unlimited users. Or score a requirement in REX right now without signing up for anything.
Get started free Analyse a requirementIBM, DOORS, IBM Engineering Requirements Management DOORS and DOORS Next are trademarks or registered trademarks of International Business Machines Corporation. Reqi is not affiliated with, endorsed by, or sponsored by IBM. Statements about IBM products on this page are drawn from IBM's published documentation, linked above, and were checked on 1 September 2026 and again on 7 November 2026. Product details change: verify with IBM before making a purchasing decision.