self hosted CRM appointment booking is a query with a hidden assumption, and the honest thing to do is name it first: this store does not sell a CRM. There is no pipeline, no lead stage, no deal board and no marketing automation anywhere in the catalog, and writing a guide that implied otherwise would be the kind of thing that costs a reader an afternoon.
What the catalog does hold is a booking tool that keeps a customer record, and an invoicing tool that keeps a client record, and both run on your own server. Whether that is enough depends entirely on which half of the query you meant.
Two different things get called a CRM
The first is a contact book with history: who this person is, what they have booked or bought, when they last came in, and what was said. Small service businesses usually mean this. A booking tool with customer records and an appointment history covers most of it.
The second is a sales system: leads arriving, stages they move through, forecasts, sequences of follow-up, and reporting on conversion. That is a different product with a different shape, and no amount of appointment software becomes it.
If you are booking appointments with people who are already your customers, you are asking for the first. If you are chasing people who are not yet customers, you are asking for the second, and nothing here is it.
What owning the copy changes
For the contact-book meaning, self-hosting changes who holds the list. Slotly keeps customers, their appointment history, services and staff hours in one database on a server you chose, with the whole booking record exportable as CSV and the database backed up from admin in one click. There is no per-contact tier, because the license counts installations rather than records, and no per-booking fee, because no booking passes through anybody else.
Try the Slotly demo ↗Live, on sample data, no sign-up.
The second useful piece is the money. Invora holds reusable clients and an item catalog, turns an estimate into an invoice, drafts every recurring cycle for a human to approve before it goes anywhere, and puts your own payment link on each unpaid invoice. Run beside a booking tool, that gives you the two records a small service business actually re-reads: what they booked, and what they were billed.
What to look for
A customer record that is not just a booking form. Look for reusable customers, a visible history per person, and a CSV import with a dry run so bringing an existing list in is a rehearsal before it is a commitment.
An export you can perform yourself. The list is the asset. An admin-side CSV export and a one-click database backup mean leaving is a decision rather than a support ticket.
An API, if you intend to join the pieces. Slotly ships an owner REST API with an OpenAPI spec, revocable bearer keys and signed webhooks on booking events, which is how an appointment becomes a row somewhere else without a person retyping it.
Honesty about the stages. If a candidate advertises a pipeline, read what a stage actually does. A status field renamed is not a sales system.
The limits, stated plainly
Slotly is a booking engine with customer records, not a CRM: no pipeline, no lead source, no sequences, no conversion reporting, and no marketing mail of any kind. It never touches a card (deposits by card go through your own Stripe account, once you switch that on), runs one business per installation, and its calendar feeds go one way. Invora is not double-entry accounting or a general ledger, never processes cards either, and emails nothing unless a person presses the button.
Joining the two is your work. There is no packaged integration between them in the box; what exists is an API on each side and a CSV in the middle. For a small operation that is usually a morning's work and then nothing. For a sales team of ten it is the wrong starting point, and the right answer is probably a CRM that is not in this catalog.
Questions people ask
Is there a CRM product here? No. The catalog has a booking tool with customer records and an invoicing tool with client records; it has nothing with leads, stages or pipelines, and there is no plan on this page to pretend otherwise.
Can the booking tool push a new customer into something else? Yes, through the owner REST API and signed webhooks on booking events, or through a CSV export. Both are owner-side and both are revocable.
Will the price rise as the customer list grows? No. The license covers the sites you run the software on, not the number of records it holds.
Where to look next
The two product pages are Slotly for the bookings and Invora for the invoicing, each with its own feature record and its own stated limits. The side-by-side compares the booking half against what the rented services offer. If the question is really about what a rented stack costs before you decide to assemble your own, read the observatory: every figure there is quoted verbatim beside the date it was read and a link to the page it came from. Prices are on the observatory; read them on the date shown there.