Custom CRM for when off-the-shelf tools fall short.

02 / 08

What a custom CRM system includes

A custom CRM system is built on one client database and includes only the parts your company uses, arranged around the way you work with clients. These are the most common:

• A client record with contacts, communication history and documents
• A sales pipeline from inquiry through quote to signature, so you can see where deals get stuck
• Quotes and contracts generated from templates and filled in with the client's details
• Invoicing directly in the CRM, or handing the invoice details over to your accounting software
• Tasks and reminders with an owner and a deadline
• Automatic notifications, for example when a quote has been waiting too long for a reply
• Roles and permissions: who sees which clients and what they're allowed to change
• An audit log, a record of who changed what and when
• A client portal where clients see the status of their project and upload or download documents

03 / 08

Example: a CRM and client portal for a tax and accounting firm

I worked on the CRM and client portal of DAU, a Slovak tax and accounting firm, through the AI agency Eturial. I wrote the security layer, meaning the Row Level Security (RLS) policies in its PostgreSQL database on Supabase, and I rebuilt the client portal and the dashboards. The system is built on Next.js 16, Supabase and PostgreSQL.

The CRM as a whole covers the client journey from first contact through quotes and contracts to invoicing. It runs on one client database, sends automatic notifications and has multi-level access with an audit log. My part was the security, the portal and the dashboards, not the whole system.

If you run an accounting or tax practice and also want to automate routine work with the documents your clients send you, see AI agents for repetitive data work.

04 / 08

How client data is protected in the CRM

I protect client data with access rights that apply directly in the database, not just in the application. Technically, this is done with Row Level Security in PostgreSQL: on every read and write, the database checks which rows the user may see or change and blocks access to the rest. The rules run inside the database, so they apply even when a logged-in user tries to get around the application's screens and requests data directly through the API. Admin access with full rights bypasses these rules, so only the server side of the system holds it, and it never reaches the browser.

Before development starts, we agree on who can do what, based on how your company actually works. The result might look like this:

• A salesperson sees their own clients, not the whole database
• An external contractor sees only the project they're working on
• A client sees only their own documents and invoices in the portal
• Someone in billing sees contracts and invoices but can't change sales stages

05 / 08

Connecting the CRM to your website, online store, invoicing and company registers

I'll connect the CRM to the tools you already use: the form on your website, your online store, accounting software, email, shared spreadsheets or Slack. An inquiry from your website or an order from your online store then goes into the CRM without anyone retyping it. Either the CRM issues the invoice itself, or it sends the details to your accounting software through its API or a file import.

I have hands-on experience connecting systems. I use my own CRM every day, and it pulls data from Gmail, Google Calendar and Slack by itself.

For a new client based in Slovakia, entering the company ID number (IČO) is enough: the CRM can fill in the company's name, registered address and legal form from the Register of Legal Entities (RPO) and its financial statements from the Register of Financial Statements (RÚZ). Both Slovak registers have public APIs. I've also worked with public registers on a project of my own: using Python and a language model, I built a tool that added financial figures and websites to the records of about 2,000 Slovak companies.

06 / 08

Migrating data from Excel or an old CRM

I'll migrate your data from Excel or an old CRM through an export, an API or directly from the database, so nobody has to re-enter client details by hand. Your old system stays in use until the new one is fully up and running. Here's how I go about it:

• We go through your spreadsheets and the export from the old system and decide where each piece of data belongs
• I find duplicates, such as the same company entered three times, and we decide together which record is the right one
• You check a test migration against clients you know well
• We run the live migration on an agreed day, so that no record is left only in the old system

07 / 08

Where AI helps in a CRM

AI helps in a CRM wherever people currently read text and retype it into the system, such as inquiries that arrive by email or data from attachments. An AI agent connected to your CRM reads them, files them under the right client and, for any step where a mistake would cost money, waits for a person's approval. If your team wants to ask about contracts and client history in plain language, I'll add an AI knowledge assistant built on your documents.

AI in your CRM works only by strict rules: it processes only what clearly matches, and a person checks the exceptions. I build AI agents the same way.

08 / 08

How much does a custom CRM cost?

A custom CRM that your company runs on every day takes months to build, but I split the quote into parts, so you don't have to order it all at once. You can also start smaller: adding a single automation to an off-the-shelf CRM takes a few days of work and starts at around €500. Running costs, meaning hosting and any AI calls, run from tens of euros to the low hundreds a month.

The cost of custom CRM development depends mainly on the scope of the first version: how many of the features listed above you need right away, how many roles and access rules need setting up, whether you want a client portal, how many systems the CRM connects to and how much old data needs migrating. After a free consultation, you get a quote split into parts, each with a specific price and delivery date. If you approve the quote or some of its parts, I build a free prototype on a sample of your data, so you can check that it will work before you make a final decision. Deployment usually takes 6 to 12 weeks.

By default I run the system on my own accounts for a monthly fee, and before any of your data is migrated, we sign a data processing agreement under Article 28 of the GDPR. I always fix bugs in the system for free. For payments, moving the system to your own accounts and the other terms, see how we work together.

I'm based in Košice, Slovakia: we can meet in person in and around Košice, and I work online with companies elsewhere in Slovakia, in Czechia and abroad. Use the form below to tell me what you use to keep track of clients and projects today, and I'll get back to you within eight hours.