I tested six practice management tools by clicking through each one the way a client does on day one, not by reading product pages. Most Karbon alternatives are internal tools wearing client-portal clothing, and this list covers the ones that genuinely work both ways.

Karbon does its core job well: it keeps jobs on schedule and email threads visible for your team, but clients don't log into Karbon. They get an email, reply in a thread, and wait for someone to follow up, which means the client experience depends entirely on how fast your team responds rather than on any system holding things together.

Accounting firms keep buying software, but almost none of it faces the client. McKinsey's January 2025 Superagency in the Workplace report found that 92% of companies plan to increase technology investments over the next three years, yet only 1% of leaders call their companies mature on the deployment spectrum.

In practice management, that gap shows up every time a client emails asking where their documents are, and Karbon has no answer for it.

Not every tool here does the same thing. Some are built around documents, others around the full client lifecycle. The distinction matters because the right fit depends less on feature count and more on where your client relationship actually breaks down.

Assembly is a post-sales client portal built for service businesses managing ongoing client relationships. Clients sign contracts, pay invoices, upload files, and message your team, all under your brand, while your team sees every interaction in one record without switching tabs. 

The portal is white-labeled, different clients can see different homepage content based on custom field tags, and recurring automations handle reminders and follow-ups on a schedule without anyone triggering them manually.

Assembly meets SOC 2 Type II, HIPAA, and GDPR standards, with encryption, permission controls, and audit logs built in. Details at security.assembly.com.

Why it beats Karbon here: Karbon organizes your team's work. Assembly organizes the client relationship, and your clients get a portal they can log into instead of an email they have to reply to.

Pricing: Starts at $39/month for one internal user and up to 50 clients.

TaxDome is built around the document lifecycle, and for accounting firms doing high-volume tax prep and compliance work, that focus is the right call. Clients receive automated file requests, sign documents through a secure portal, and check job status without emailing your team.

Mobile access cuts most of the back-and-forth that slows collection, while role-based permissions let larger firms control visibility across staff and clients.

TaxDome's limits show up in broader relationship management. The portal is built around documents and workflows, so if your clients need a space that also handles billing or ongoing messaging, you'll reach the edges of what it was designed to do.

Pricing: Starts at $800/year with a one-year commitment.

Canopy lets firms activate features independently, so document storage, e-signatures, billing, and workflow tools can each be turned on or off depending on what a given service line needs, with optional add-ons priced separately.

Clients can share documents, track progress, and sign without calling the firm, and for tax and compliance work specifically, time tracking, invoicing, and document management connect in a way that creates a clean handoff from your team to the client.

The real limit is customization. Going beyond Canopy's default structure means paid add-ons, and some changes simply aren't possible at the lower plan tiers, so firms that want detailed control over the client experience will find that Assembly gives them considerably more room.

Pricing: Starts at $74/user/month for the Starter plan.

When a client approves a proposal in Cone, a project opens automatically and the client's portal goes live at the same moment. That removes the manual handoff that most firms handle through a separate email.

Clients track milestones and receive Stripe invoices automatically, while the time tracker feeds directly into billing, so the proposal-to-invoice flow cuts out the steps that usually create delays.

The gap shows up when a project closes, because the client has nowhere to go, and there's no persistent portal for the ongoing relationship. For retainer-based work that runs month to month, that limitation matters.

Pricing: Starts at $9/user/month for unlimited clients and proposals.

Dubsado connects proposals, contracts, and invoices in a single workflow so a client receives a proposal, signs, and pays without ever leaving the platform. Automations fire follow-ups and reminders based on client activity, and templates keep the onboarding experience consistent across clients, regardless of who on your team is handling it.

Where it runs out of steam is everything that comes after. Reporting is limited for multi-user firms, the interface shows its age compared to newer tools on this list, and if you need a portal that grows with the client relationship past onboarding, Dubsado won't carry it far.

Pricing: Starts at $335/year.

Client Hub solves one problem, which is getting documents from clients without chasing them. The portal gives clients a clear task list of what's needed, sends automatic reminders when items are overdue, and integrates with QuickBooks so communication stays linked to the accounting records it belongs with.

For firms handling a high volume of daily requests, that structure makes outstanding items visible to both sides and removes the manual follow-up entirely.

There's no built-in billing, no workflow management, and no branded portal customization, so firms that need capabilities beyond document exchange will need to pair it with another tool.

Pricing: Starts at $49/user/month.

The portal your clients log into says more about your firm than your website does, because it's where they decide whether working with you is easy or frustrating. That judgment happens every time they need to find a file or check where a project stands.

Deloitte's CX Study 2025 puts a number on that gap, finding that customer experience is a high priority, but only 20% successfully connect that investment to measurable financial outcomes, and the difference almost always lives in the tools.

For document-heavy compliance work, use TaxDome or Client Hub. For project-based services, use Cone or Dubsado. If you want one branded space that handles the full post-sales relationship, Assembly is the answer.

The right portal isn't the one with the longest feature list. It's the one your clients open without being asked.