You do not need a thirty-page document. One carefully written page is enough to make the quotes you receive comparable, and to protect both sides from arguing later.
Start with one sentence
Write what the project does in a sentence, with no jargon: "a site where a patient books a clinic appointment and gets a WhatsApp confirmation". That sentence alone prevents half of all misunderstandings, because it forces you to name who uses it and what happens at the end.
Then who uses it
List the types, not the names: unregistered visitor, registered customer, reception staff, manager. For each, write the most important thing they do. That list determines the number of screens and the permission rules, the two biggest cost drivers in any system.
Then the main journey, step by step
- The visitor lands on the home page and sees the services.
- They pick a service and see the available times.
- They book and enter their name and number.
- They get a confirmation, and the booking appears for reception.
One journey written like that is clearer than ten pages of description, and a developer reading it knows immediately what is being asked.
And finally: what is out of scope
This is the most important section and the most neglected. Say plainly what you do not want in version one: "no online payment yet", "no mobile app", "no reporting dashboard". It protects your budget from inflation and the developer from expectations they never priced.
A template to copy
- What it is: one sentence.
- Who uses it: the types, and the main action for each.
- The main journey: four to six steps.
- Out of scope: what we do not want now.
- Content: who prepares it and when.
- The date you want, and whether any date is immovable and why.
What to expect next
Send that page to three suppliers and ask for a quote. For the first time the quotes will be comparable, and you will notice something useful: the one that replies with sharp questions about your page is usually better than the one that replies with an instant price.