01 / Client documents and briefs
Notion
Notion is a useful starting point when a client only needs the pages containing their brief, notes or deliverables. Its guest access is scoped to pages, with a guest allowance that depends on the plan.
Set it up: Invite from the page’s Share menu. Check that the person is being added as a guest, and skip the offer to turn them into a workspace member.
The catch: This fits a defined client space. If the person needs broader workspace membership, price that role separately before inviting them.
02 / One board per client
Trello
Trello works well for a client approval board or a shared delivery checklist. On Standard and Premium, a guest who belongs to only one board in that workspace does not add a billable guest seat.
Set it up: Keep the client as a board guest and check their other board memberships before adding them to another board in the same workspace.
The catch: Multi-board guests on Standard and Premium cost the same as workspace members, with prorated charges. Enterprise has a different rule: its multi-board guests are not billed.
03 / A dedicated client conversation
Slack
Slack’s single-channel guest role is useful when the shared work is a conversation in one channel. Guest roles require a paid host plan; the free guest allowance is tied to its paid active membership.
Set it up: Ask a workspace administrator to invite the client as a Single-Channel Guest and assign the intended channel. Check the remaining guest allowance first.
The catch: Multi-Channel Guests are billed like regular members. This comparison covers guest roles; Slack Connect is a separate collaboration arrangement.
04 / Client tasks and project reviews
Asana
Asana guests can work on explicitly shared tasks, projects or teams. Its documentation says guests do not count toward membership when an entire organization is upgraded to a paid plan.
Set it up: Invite the client using an email outside your organization’s approved domain, then share only the project or tasks they need.
The catch: Someone using your organization’s domain is a member rather than an external guest. Being a guest elsewhere does not remove their paid license in their home organization. Check division or workspace arrangements separately.
Put it to work
Before you invite the next client
- Choose the smallest shared space that supports the work: page, board, channel or project.
- Check both the guest role and the host plan. A free guest seat can still require a paid workspace.
- Review existing invitations before adding access. A second board or a member conversion can change billing.
- Give one person responsibility for removing access when the engagement ends.
Common questions
Which option should an agency start with?
Use the tool that already holds the client’s work when its guest boundaries fit. A document review suggests Notion; a single delivery board suggests Trello; a conversation suggests Slack; shared task ownership suggests Asana. These are workflow matches, not a ranking of overall product quality.
Does free guest access mean unlimited clients?
No. Guest allowances, access boundaries and host-plan requirements differ. Review the current official policy before adding a batch of clients, and inspect the billing preview when changing a person’s role.
How this list was researched
Documented rules, with the exceptions visible.
Billproof reviewed the linked vendor documentation on October 21, 2026. Entries were selected for a documented billing control and a distinct workflow. The order is for reading, not a scored ranking. This is documentation research, not a hands-on product benchmark.
Plan terms and interfaces can change. Check the linked source and the settings in your own account before making a change. These source links are editorial and carry no affiliate commission.