NBS Chorus is a cloud-based specification writing platform built around structured content libraries. It integrates with BIM tools like Revit, ArchiCAD, and Vectorworks, and allows real-time collaboration across teams. Its Masters feature lets firms build libraries of commonly used clauses, and it supports Uniclass classification throughout.
For practices that need to produce formal, auditable specifications — particularly on larger commercial or public-sector projects — NBS Chorus has been a reliable choice. The platform's strength lies in its structured approach to clause selection and its deep integration with NBS's own content libraries.
NBS Chorus is fundamentally a specification writing tool. It does one thing, and it does it in a particular way — clause-by-clause, manual selection from pre-written libraries. For architects working on smaller or mid-scale projects, this process can feel heavy. The platform requires significant upfront investment in both licensing costs and time to learn the system, build your Masters library, and integrate it into your workflow.
The bigger limitation is scope. NBS Chorus doesn't help with schedules, quality checks, material research, drawing coordination, or any of the other documentation tasks that consume an architect's time. It's a specification tool in a world where architects need a documentation platform.
Avoice is built as a complete AI workspace for architectural practice — not just specifications, but the full range of operational work that surrounds every project. Where NBS Chorus asks you to manually select clauses from a library, Avoice uses AI to generate specifications based on your project data, drawings, and requirements. The result is a complete draft specification in days rather than weeks, which your team then reviews and refines.
But specifications are just the starting point. Avoice also handles schedules and quantities, quality control checks, material research, construction administration, and custom documentation workflows. It's a single platform that replaces multiple tools and manual processes across your practice.
Both tools produce Uniclass-compliant specifications, but they get there differently. NBS Chorus relies on manual clause selection from curated libraries — a structured, controlled process that some practices prefer. Avoice uses AI to generate specification drafts from your project context, then lets you review and edit. The trade-off is speed versus manual control.
On collaboration, both platforms support team working. NBS Chorus offers real-time editing within the specification, while Avoice provides collaboration across the entire project workflow — specs, schedules, QA, and documentation in one place.
On pricing, NBS Chorus licensing can be significant, particularly for smaller firms. The Small Works and Designer tiers offer more affordable entry points but with reduced functionality.
If your practice primarily needs a structured clause library with BIM integration, and you have the budget and team to manage the system, NBS Chorus remains a solid choice. It's particularly strong for large practices with dedicated specification writers who want granular control over every clause.
If you're looking for something faster, broader, and more affordable — especially if you're a small or mid-sized firm where the same people doing design are also writing specs, managing schedules, and coordinating documentation — Avoice offers significantly more capability in a single platform. The AI-powered approach means less manual work, faster turnaround, and a tool that grows with your practice rather than adding overhead to it.
NBS Chorus set the standard for digital specification writing in the UK and beyond. But the standard is evolving. Architects in 2026 don't just need a spec writer — they need an operational platform that handles documentation end to end. That's the gap Avoice was built to fill.
