Comparison
Sideline vs. Assembly
Assembly, formerly Copilot, is probably the best-designed portal platform in the category. The trade-off is a modular, per-seat, client-capped pricing model that punishes exactly the kind of agency Sideline is built for.
Assembly is the modular platform
A beautifully built client portal with invoicing, proposals and eSignatures, forms, messaging, an app store, and an AI assistant, aimed at service firms from accounting to real estate. Pricing is per internal user with client caps: $59/mo (1 user, 50 clients) to $499/mo for unlimited clients ($399 annual), plus $39 to $59 per extra seat.
Sideline is the flat-priced queue
The request workflow done completely, intake, queue with board and calendar views, client portal, internal notes, time tracking, reports, at $49/mo flat with 5 seats and unlimited clients from day one. No modules to assemble, nothing your clients need training for.
| Feature | Sideline | Assembly |
|---|---|---|
| Starting price | $49/mo flat, 5 seats, unlimited clients | $59/mo ($39 annual), 1 user, 50 clients |
| 5 seats + unlimited clients, realistic plan | $49/mo (Studio) | $399 to $499/mo (Advanced) |
| Client limits | None, on any plan | 50 (Starter) / 500 (Professional) / unlimited from Advanced |
| Intake forms | Yes | Yes (Forms app) |
| Request views | List, board, calendar | Task lists, no project boards |
| Time tracking | Built in, all plans: a per-person timer that follows you across devices, filterable reports, CSV export | None native at any tier (no timer, timesheet, or API resource) |
| AI connector (Claude / ChatGPT / MCP) | Included, one-click OAuth, per-user scoped | MCP server shipped July 2026; admin-only, staff and client users cannot connect |
| AI | Polish + Write-for-me, included | AI assistant + AI-powered CRM |
| Flexible staffing without seats | Specialists sign in with their own email; personal contact details stay private | Team accounts, standard |
| Invoicing & storefronts | Not yet, retainer billing is next on the roadmap | Native, all tiers |
| Proposals, contracts & eSignatures | No | Yes, all tiers |
| CRM | No, your CRM keeps that job | Included |
| White-label | In development; included in the $49 plan when it ships | Custom domain from $149; full white-label from $399 (annual) |
| HIPAA / audit log | No | Advanced tier and up |
| File storage | 500GB (+$19/mo per 500GB) | Not published |
| Free trial | 14 days, no card | 14 days, no card |
| Hide your client list & team roster from staff | Agency setting per page: client list, team roster, reports. Client list hidden by default | Restricting staff from all clients requires the Advanced plan ($399/mo); roster hiding not documented |
| Queue ranks itself, with reasons | Smart Focus ranks each person's queue and says why in plain language | No priority field exists in their Tasks app |
| AI suggests field updates from the thread | Suggests status, due date, and priority from the conversation; you accept or ignore | Not offered |
| Client-set priority order | Drag in the list or on the board; the order is shared, so clients can set your priorities | Not documented |
Assembly details from assembly.com/pricing and their plans guide as of July 2026; storage quotas are not published. Check their site for current numbers, and tell us at hello@sideline.io if anything here is out of date.
Our honest take
Assembly deserves its reputation: it's the most polished portal in the category, and if you need contracts, eSignatures, and invoicing under one roof, or HIPAA compliance, it earns its price for firms that use the whole stack.
The catch is the pricing geometry. Portals exist because of clients, but Assembly meters both your seats and your client count, so a five-person agency with a normal client roster lands at $399 to $499/mo before extras. And the day-to-day delivery layer is comparatively thin: task lists without boards, no native time tracking. That's the half Sideline does completely, for roughly a tenth of that.
If the deliverable is paperwork, pick Assembly. If the deliverable is work, pick the tool built around the queue.
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