The short answer
Yes, one site. Two routes, decided on the first screen. A family wants vetting, fees and speed. A candidate wants roles and a simple way to register. Each gets its own pages, its own language and its own form, and neither has to read the other's content to get anywhere.
Two separate websites is the wrong answer, and so is one undifferentiated site that talks to nobody.
Why not two sites
Splitting into two domains doubles the hosting, the updating and the search footprint, and halves the authority of each. It also breaks the thing that makes an agency credible to both sides: a family wants to see that good nannies want to work with you, and a nanny wants to see that you represent decent families.
The exception is a large agency running genuinely separate brands. If you are one office placing nannies, one site with two routes is right.
What the first screen has to do
Two clear entry points, side by side, above the fold, in the same visual weight. One says something like "I am looking for a nanny", the other "I am looking for work". Not a menu item buried under About. Not a small link in the top corner.
Underneath them, a short line about what you do and where you place. That is the whole job of the first screen. Everything else on the home page is secondary to sorting the visitor into the right lane.
What sits under the family route
The vetting process, step by step. Fees, stated. The types of help you place, from permanent nannies to temporary cover, maternity nurses and au pairs. How the process runs and how long it takes. Your team, with names and faces. Testimonials from families. The family enquiry form.
The tone is reassurance. This parent is handing over their child to someone you introduced.
What sits under the candidate route
Current roles, or at least the kinds of roles you place and the areas you cover. What you require: qualifications, first aid, references, background checks. What registration involves and how long it takes. What you do not charge them, which is normally any fee for finding them work. Testimonials from nannies. The registration form with CV upload and availability.
The tone is respect and clarity. Good candidates have a choice of agencies.
Keep the navigation honest
The main navigation should reflect the split rather than hiding it. A workable shape is a small route switcher in the header, with the menu changing to suit the lane the visitor is in, and a persistent link back to the other route for the person who chose wrong.
Do not build a login wall in front of either route. An agency site is a shop window; the gated parts belong in your CRM, not in front of your content.
Shared pages that serve both
About, team, contact, privacy and the blog serve everyone and should not be duplicated. Duplicate content across two routes splits your search results and doubles your editing.
Where a page genuinely differs, such as testimonials, keep one page with two clearly labelled sections rather than two thin pages.
The forms must not be the same form
This is where most agency sites fall down. A single generic contact form for both audiences means every enquiry needs a triage call and every candidate registration arrives without a CV.
The family form asks about children's ages, hours, live-in or live-out, start date, location and budget. The candidate form asks about experience, qualifications, first aid, checks held, availability, driving and CV upload. They route to different places in your CRM and trigger different notifications.
What search engines make of it
Two routes help rather than hurt, because the searches are genuinely different. A family searches for a nanny agency in their town. A candidate searches for nanny jobs in the same town. Each route can carry its own page titles, descriptions and location pages, and neither has to compromise for the other.
One site with two well-built routes outranks two half-maintained sites almost every time.
Where this sits
Two routes from the first screen, separate pages, separate forms and shared trust content are how we build a nanny agency website, and the same audience-splitting pattern appears across our childcare websites. The packages are on pricing. Sort the visitor in one tap and both sides get a site written for them.