Assembly (formerly Copilot) alternative
Assembly vs ClientOS: rent a portal, or own one.
Assembly, formerly Copilot, is a hosted client portal for service firms, with messaging, billing, contracts, forms and an AI app builder. ClientOS is a self-hosted client portal for agencies, paid for once.
The short answer
Assembly is polished and strong on compliance, but it limits clients and seats by plan and takes a fee on payments. ClientOS has no client or seat limits, takes no cut of your sales and runs on your own server.
Assembly
From $29 a month, billed yearly
ClientOS
$490 once
Side by side
Assembly and ClientOS, row by row.
Assembly details from its public pages, checked 29 October 2026. Sources are listed at the foot of this page.
Three years of cost
A subscription never ends. A license does.
Assembly bills every month for as long as your agency uses it. ClientOS Standard is $990 once, with 12 months of updates, and keeps running on your server after that. You also pay for your own server, which you choose.
$2,574kept over three years, before server costs
What the portal costs, by year
Assembly Professional at $1,188 a year, list price on 29 October 2026, before extra seats or add-ons.
A fair reading
Where Assembly is strong, and where it pinches.
Assembly is a good product, and for some agencies the right one. Here is what it does well, and why agencies on it look at ClientOS.
What Assembly does well
A polished client experience
Store, invoices, subscriptions and payment links, with no merchant account to set up.
Extend it without code
An AI app builder and embeds for Notion, Airtable, ClickUp, Calendly and more.
Compliance depth
SOC 2, a HIPAA BAA on Advanced, audit log, enforced MFA and SSO on Enterprise.
Why agencies move to ClientOS
A cut of every sale
Assembly adds a 0.7% to 2% store fee, plus invoice and subscription fees, on top of card processing. ClientOS takes nothing.
Limits on clients
Starter allows 50 active clients and Professional 500. ClientOS has no client limit.
White-label without the upgrade
A custom domain and removing the Assembly badge start on Professional. ClientOS is white-label on every package.
Choose Assembly if
- You need SOC 2 or a HIPAA BAA from your vendor
- You want to build custom portal apps with AI
- You do not want to run a server
Choose ClientOS if
- You do not want a fee taken from your sales
- You have many clients and do not want tier limits
- You want PayPal or crypto as well as Stripe
Moving from Assembly
Switch in a day, not a quarter.
- Step 1
Export from Assembly
Take your clients out of Assembly as a CSV file. Keep Assembly running until the new portal is live.
- Step 2
Install ClientOS
One command on your own server, about ten minutes. The installation guide walks through it.
- Step 3
Bring your clients in
The CSV import maps your columns, and each client can sign in straight away.
- Step 4
Or let us do it
On Premium and Custom our team installs ClientOS on your server and moves your data for you.
FAQ
Assembly vs ClientOS, asked and answered.
Is ClientOS a good Assembly (Copilot) alternative?
Yes, for agencies that sell services and want to own their portal. ClientOS has a store, checkout, orders, messages, invoices, subscriptions and a help desk, with no client limits and no fee on payments.
Does Assembly charge transaction fees?
Yes. On top of card processing, Assembly lists a store fee from 0.7% to 2% by plan, and further fees on invoices and subscriptions. ClientOS charges no fees on your sales; you pay only your payment provider.
Can I move from Assembly to ClientOS?
Yes. Export your clients from Assembly as a CSV file and bring them in with ClientOS’s CSV import, which maps your columns. On the Premium and Custom packages our team installs ClientOS and moves your data for you.
Do I need to be technical to run ClientOS instead of Assembly?
No. Installing is one command on a Linux server with 2 to 4 GB of RAM, and takes about ten minutes. On Premium and Custom we install it for you, connect email and payments, and hand over a working portal.
Sources, checked 29 October 2026. Assembly is a trademark of its owner; ClientOS is not affiliated with it. Prices change, so check Assembly’s site for its current terms.
Your agency, your portal, your server.
Get ClientOS and run sales, delivery, billing and support from one place you own.