Karbon
Practice management for accounting firms built around a shared email inbox, with workflows, client portal, billing and the Kai AI coworker
Some outbound links may earn The AI Ledger a commission. Editor scores and verdicts are never influenced.
About Karbon
Karbon is practice management software for accounting firms that puts the team's email at the centre of work. Emails from Gmail or Outlook become trackable work items, alongside recurring jobs and checklists, a client portal for tasks and document sharing, time tracking, billing and payments, and reporting on capacity and profitability. In June 2026 it launched Kai, which it calls an AI coworker, in early access, together with an AI meeting notetaker, a public MCP server for external AI tools and agentic period close that flags transactions for review; document validation and a close check rule builder have also shipped.
Karbon's integrations page lists Xero, Xero Practice Manager, QuickBooks Online, Ignition, Dext, TaxDome, Gmail, Outlook and Zapier, and the company says Kai draws on more than 80 native integrations. Published pricing is $59 per user per month annually on Team and $89 on Business, with monthly billing for teams of four or more and custom Enterprise pricing; the site offers other currencies including sterling. Karbon says it has been G2's top-ranked accounting practice management software for 19 consecutive quarters, and in October 2026 it appointed Stuart Totman as chief technology officer.
It is positioned for growing firms of roughly five to several hundred staff, in the UK, US, Australia and New Zealand.
Key Features
- Email from Gmail or Outlook turned into trackable work
- Recurring jobs, checklists and capacity reporting
- Client portal with automated requests and document sharing
- Kai AI coworker, AI notetaker and MCP server (early access in 2026)
- Integrations with Xero, Xero Practice Manager, QuickBooks Online, Dext and Ignition
Our in-depth review
Karbon is where many growing firms end up when spreadsheets, a shared inbox and a basic job tracker stop coping. It joins email, recurring work, client requests and billing into one place so a manager can see who is doing what for which client, and it is now adding AI across that workflow.
What it does well. The email-first design is the core strength. Turning client emails into assigned, trackable work fixes the most common reason jobs slip, and the client portal and automated requests reduce chasing. Integrations cover what a UK firm needs, with Xero, Xero Practice Manager, QuickBooks Online, Dext and Ignition all listed. The AI programme is substantial: Kai, a meeting notetaker, an MCP server and agentic period close checks put Karbon ahead of most practice tools, and its long run at the top of G2's rankings reflects strong user satisfaction. Pricing is now published, which makes comparisons easier.
Where it falls short. It is not cheap. At $59 to $89 per user per month on annual terms, a fifteen-person firm is looking at a significant annual commitment, and monthly billing needs at least four users. Kai is still in early access, so firms should judge it on what ships rather than the roadmap. IRIS and Sage practice suites do not appear among the main integrations, so firms on those should check what syncs. Implementation takes real effort: templates, workflows and client data need setting up, and the benefit depends on the whole team working in Karbon. Time savings quoted are the company's own.
Best for. UK practices of five to a few hundred staff on Xero or QuickBooks that want a single workflow system with strong email handling and are prepared to invest in setup. Smaller firms watching cost may prefer Financial Cents, and firms whose main pain is fees and engagement letters should pair Karbon with Ignition rather than expect it to do proposals. In a trial, run one full month of VAT and payroll work through it and check how client emails are triaged.
Verdict. The most complete practice management choice in the directory for growing Xero-based firms, now with a serious AI roadmap. The price and setup effort are justified for firms ready to standardise how they work.
At a glance
- Category
- Client communications
- Best for
- 11–50 practice
- Editor's score
- 4.4 / 5
- Pricing
- Team $59 per user per month and Business $89 per user per month, billed annually; Enterprise custom
- Last verified
- 2026-10-10
The most complete practice management option here for growing Xero firms, with strong email workflow and a serious AI roadmap; priced accordingly.
Integrations
- Xero
- Xero Practice Manager
- QuickBooks Online
- Ignition
- Dext
- TaxDome
- Gmail
- Outlook
- Zapier
Get the weekly brief
New AI tools for accountants land every week. Get the 5-minute Friday brief, free.