Bespoke CRM for a small business: the internal app I built when leads piled up

A bespoke CRM is customer relationship software built around the way your business already works, rather than a product you rent and bend your process to fit. For most small businesses, it is not the first thing to buy: a standard CRM, or even a spreadsheet with automatic reminders, does the job for far less.

I built one anyway, for a client whose problem had become the number of leads. Between the websites, the SEO and the cold email campaigns, I bring this client about ten prospects a day, and at some point the team could no longer keep up. This guide explains how to tell whether you need a bespoke CRM, and what that app covers.

I also build software for my own use, not for sale, so I know what it feels like to need something and build the solution myself. If you are still working out where automation fits in your business, start with my guide to AI for small businesses.

What a bespoke CRM is, and how it differs from an off-the-shelf CRM

A CRM (customer relationship management tool) keeps track of every prospect and client: who they are, what they asked for, what was said and what happens next. An off-the-shelf CRM is a product you subscribe to, usually per user and per month, and configure within the limits its makers set. A bespoke CRM is an application coded for one business, which does what that business needs and nothing more.

There is a third option between the two: a spreadsheet or a standard CRM, plus automations that pass information from one tool to another. Here is how the three compare.

Why a client asked me for an internal app

Pilotech installs air conditioning, heat pumps and ventilation in Paris and the Île-de-France. It called me in an emergency when its WordPress website was hacked. I recovered the site and built a new one, and we have worked together for two years now, on SEO, cold emailing and websites.

The leads arrive through the website forms and by phone. As their number grew, the problem changed: it was no longer finding prospects but keeping up with them. I was bringing in so many that the team could not handle them all, and a prospect who is never called back is a lead the business paid to get, then lost.

So the founder asked me to build an automation app, with a simple brief: see everything clearly, and never forget to call a prospect back or answer one. The SEO side of that growth, from the first page to the first enquiry, is told in the Pilotech SEO case study, and the cold email side in my cold email case study on architects.

What the app manages

The app is custom-coded. It is an internal tool, used by the business itself rather than by its clients, and it brings together:

• Prospects, so that every enquiry is in one place and none is forgotten.
• Jobs, meaning the installations themselves.
• Communication with the employees.
• The calendar.
• Accounting analytics, to follow the figures.
• AI and phone integrations.

Prospects and appointments are what most CRMs are designed for. Jobs, messages to the team and accounting figures usually live in other software: job management tools, messaging apps and accounting packages. When the work goes that far beyond the sales pipeline, a bespoke app starts to make sense.

I will not show screenshots or describe the app further: it holds the client’s prospects, jobs and figures, and they stay private. The questions below, on the other hand, apply to any small business.

Bespoke CRM or off-the-shelf: five questions to decide

These are the questions to answer before anyone, me included, writes a line of code.

1. How specific is your process?

If your sales follow the classic path (enquiry, quote, won or lost), any standard CRM fits: you rename the stages, add a few fields and you are set. The case for a bespoke app starts when an enquiry turns into something else, such as a job with a date, a team and an invoice, and no single product covers the whole chain without copying data between tools.

If you work in a trade, also look at the job management software made for installers and builders, which combines quotes, jobs, schedules and invoices. It may already fit your process as it is.

2. How many people will use it, and for what?

Off-the-shelf CRMs are usually priced per user and per month, so every login adds to the bill. Several have a free plan, HubSpot’s being the best known, with limits on users and features. A bespoke app has no licence fee per user, and it can show each role only what it needs: whoever answers the phone does not need the accounting figures.

For one or two people with a simple sales process, a free or low-cost CRM is hard to beat.

3. Which tools must it connect to?

List everything the CRM has to work with: your mailbox, your phone line, your calendar, your website forms, your accounting software, an AI assistant. Then read the integrations page of the CRM you are considering. If everything is there, you probably do not need a bespoke app.

If you would need a chain of automations to fill the gaps, my comparison of Zapier, Make and n8n shows what those tools cost. Each tool in the chain is one more subscription, and each automation one more link that can break; a bespoke app connects to the same services directly, in code your developer controls.

4. What will it cost over three years?

Compare the two options over the life of the tool, not over one month:

• Off-the-shelf: the price per user × the number of users × 36 months, plus paid add-ons and the automation tools that fill the gaps.
• Bespoke: the build, paid once, plus hosting, maintenance and the services it uses, such as an AI API billed by usage or a phone provider’s subscription.

For five users over three years, you pay the monthly price of a seat 180 times, before any add-ons. The subscription usually wins in the first year; over three years, with several users and add-ons, the result can tip the other way.

5. Who will maintain it?

Software is never finished. The services it connects to change their rules, security fixes come out, and the business asks for new features as it grows. With an off-the-shelf CRM, the vendor takes care of that. With a bespoke one, your developer does, so ask before you sign: who maintains it, how quickly they respond and what it costs. Ask too who will own the code and the hosting account: if both are in your business’s name, you can change developer without starting again.

If you build it yourself with AI, you are the one maintaining it. My guide on how to build an app with AI sets out what you can realistically do alone. Before real client data goes into it, check that your AI-built app is not leaking data.

Put side by side, the answers look like this:

My tutorial to automate lead follow-up sets up those alerts and reminders for free with Google Apps Script.

How I work on a bespoke CRM project

I build everything myself. For app projects, I ask for 30% or 50% of the price upfront and the rest at delivery. AI has changed how I build: my delivery times have shrunk, which sometimes leaves me room to look for extra solutions and deliver a more complete app.

What I need from you depends on what the app must do. For automations like the app above, I need access to the mailbox, for example. The checklist at the end of this guide lists what to prepare before you talk to any developer.

Plan for GDPR from day one

A CRM is full of personal data: names, phone numbers, email addresses, notes from calls. Write these rules into the specification rather than leaving them for a later update:

• Access: who can see and change what.
• Deletion and export: how to remove or hand over one person’s data when they ask.
• Retention: how long each record stays in the app, and what happens after that.
• Objections: the UK’s electronic marketing rules (PECR) let you email limited companies without their consent, but the ICO still says to honour their opt-out requests. Keep those addresses on a do-not-contact list rather than deleting them, and check every new import against it.

On retention, the ICO’s guidance on storage limitation says the law sets no fixed period. You decide how long to keep data according to why you hold it, and you must be able to justify that choice.

You cannot keep data just in case, so review what you hold and delete or anonymise what you no longer need. An app that flags records nobody has touched for a set period makes that review quick.

If the app sends client data to an AI service, check what that service does with it before anything is sent. My article on ChatGPT and GDPR explains what you can and cannot share.

Before you commission a bespoke CRM: a checklist

1. Write your process on one page, from first contact to paid invoice: who does each step, and where things get lost today.
2. Mark the steps where information is copied by hand or forgotten.
3. Count the people who will use the tool, and note what each one needs to see.
4. List every tool it must connect to: mailbox, phone, calendar, website forms, accounting.
5. Gather the data you want to bring in: spreadsheets, contact lists, exports from your current tools.
6. Run the cheap version for a month: a free CRM or a spreadsheet with alerts.
7. If the same problems keep coming back, that page is your brief, and the start of a quote.

The clearest sign is the one my client had: more prospects than the team could follow. On its own, that calls for alerts and reminders, which a standard CRM can provide. When the work also runs on into jobs, staff and accounts, as it did for my client, it is worth finding out what a bespoke app would cost.