The Side Agent: Rethinking Browser Automation for Belgian SMEs

💡 Key Takeaways

• Pragmatic: Solves one specific pain point, not everything at once.
• Private: All data stays in your browser. Nothing hits a server.
• Human in control: You authenticate, you initiate, you review. The agent assists.
• Zero recurring cost: No SaaS subscription, no infrastructure to maintain.
• Fast to deploy: A browser extension, not an enterprise IT project.

If you have ever spent an afternoon looking up VAT regimes on Intervat one number at a time, you already understand the problem this article is about. You log in via itsme, navigate to the right page, type a VAT number, read the result, go back, type the next one. Repeat fifty times. Or a hundred.

This is not a technology problem. It is a repetitive-task problem. And we built a new kind of tool to solve it.

📋 The Intervat Problem: A Pain Every Belgian Accountant Knows

Intervat is the Belgian Federal Public Service Finance portal for VAT declarations and regime lookups. Every year before March 31, Belgian businesses must file their Listing 725: the annual declaration of VAT clients (Art. 53quinquies CTVA). To prepare it, accountants need to verify VAT regime information for each client.

The manual workflow looks like this:

1. Authenticate on Intervat via itsme or eID
2. Navigate to the VAT regime search page
3. Type one VAT number
4. Read the result (regime code, status, dates)
5. Copy it into your spreadsheet
6. Go back and repeat for the next client

For a fiduciary managing 80 to 200 clients, this takes 3 to 5 hours of pure mechanical work. The risk of copy-paste errors is real, and there is no audit trail.

The portal was designed for looking up one number at a time. There is no batch mode, no API, no export function.

🤖 What is a Side Agent?

A Side Agent is a browser extension that lives in Chrome's side panel and helps you with a specific, well-defined task. The name says it all:

• "Side": it sits in the side panel of your browser, working alongside you, not instead of you.
• "Agent": it acts on your behalf within defined boundaries, filling forms, reading results, organizing data.

The key difference from traditional automation:

Here is how a Side Agent compares to traditional approaches:

Aspect	Traditional RPA	SaaS Tool	Side Agent
Runs on	Remote server or VM	Cloud platform	Your browser
Data handling	Data sent to server	Data in vendor's cloud	Data stays local
Authentication	Service account or bot login	OAuth or API key	Your own login (itsme)
Infrastructure	IT setup required	Account creation	Install extension
Cost model	Monthly license (hundreds/month)	Monthly subscription	One-time or free
Control	Runs unattended	Vendor manages	You initiate and review
Scope	Enterprise workflows	Multi-feature platform	One focused task

The philosophy is simple: solve one pain point extremely well, with minimal moving parts.

🔍 Case Study: The Intervat Side Agent

We built a Side Agent specifically for Intervat VAT regime lookups. Here is how it works in practice.

How It Works

Step by step:

1. Install the Chrome extension (one time, takes 30 seconds)
2. Authenticate on Intervat yourself via itsme. You own the session.
3. Navigate to the VAT regime search page
4. Open the Chrome side panel and import your Excel file with VAT numbers
5. Click Start. The agent fills in the search form, reads the result, moves to the next number automatically.
6. Export the enriched Excel with all results when it finishes

You can watch it work or switch to another tab. It runs in the browser, not in the background.

What the Output Contains

Your original Excel comes back with these columns added:

• intervat_status: lookup result status
• intervat_company_number and intervat_company_name: official company data
• intervat_start_scheme_date: when the current scheme started
• intervat_scheme_code: the VAT scheme code
• intervat_regime_1A, intervat_regime_1B, intervat_regime_2: regime details
• intervat_is_active and intervat_is_stopped: current status flags
• intervat_looked_up_at: timestamp for your audit trail

Privacy and Security

This is where the Side Agent approach really shines for Belgian businesses concerned about GDPR.

• Zero server infrastructure: there is no backend. No API calls to external services. The extension runs entirely in your browser.
• Data never leaves your machine: your Excel file is processed locally. Results are stored in Chrome's local storage.
• GDPR by design: there is literally no data processor because there is no backend. Your client VAT numbers never touch a third-party server.
• Local deduplication: if your Excel has the same VAT number on 5 rows, the agent looks it up once and propagates the result to all matching rows.
• Session recovery: results are cached locally so you can resume if the browser closes.

The Numbers

Metric	Manual	Side Agent
Time per lookup	~2-3 minutes	~15-20 seconds
100 VAT numbers	3-5 hours	25-30 minutes
Copy-paste errors	Inevitable	Zero
Audit trail	None	Automatic timestamps

The speed is limited by Intervat's own page load times, not the extension. The agent works as fast as the portal allows.

⚖️ When a Side Agent Makes Sense (and When It Does Not)

Good Fit

• Repetitive data entry on web portals: government, banking, ERP systems that lack batch operations
• Personal authentication required: portals behind itsme, eID, or 2FA where you cannot delegate credentials to a bot
• Data sensitivity: situations where sending client data to a cloud service is not acceptable
• One-at-a-time portals: websites designed for individual lookups with no API or export

Not the Right Tool For

• Cross-system orchestration: connecting CRM to accounting to email requires tools like n8n, Make, or Zapier
• 24/7 unattended operation: if you need something running while you sleep, use traditional backend automation
• Portals with proper APIs: if the service offers an API, use it directly. A Side Agent is for when there is no API.
• Multi-day processes: Side Agents work within a browser session. For workflows spanning days, use a different approach.

🇧🇪 Why This Matters for Belgian Businesses

Belgium has a unique combination of factors that makes the Side Agent approach particularly relevant:

Complex regulatory environment. Federal, regional, and community-level obligations mean Belgian businesses interact with dozens of government portals. Many of these portals are web-only with no API.

itsme authentication. Belgium's itsme digital identity system is excellent for security but makes credential delegation impossible. You cannot give a bot your itsme credentials. A Side Agent works within your authenticated session.

GDPR caution. Belgian businesses are rightly cautious about sending client data to external services. A browser-based tool that never phones home eliminates this concern entirely.

High labor costs. At EUR 48.2 per hour (among the highest in Europe), even small time savings compound quickly. Turning 5 hours of manual lookups into 30 minutes of supervised automation pays for itself immediately.

Practical culture. Belgian SMEs and fiduciaries value pragmatic solutions over flashy platforms. A tool that does one thing well and costs nothing to run fits the Belgian business mindset.

🚀 Beyond Intervat: Other Side Agent Possibilities

The Intervat extension is one example. The same pattern applies wherever you have a web portal designed for single-user interaction that needs to handle batch operations:

• MyMinfin: downloading tax documents for multiple clients
• KBO/BCE: verifying company registration data in bulk
• ONSS/RSZ: checking social security status for contractors
• Banking portals: preparing batch payment files from invoice data
• Real estate platforms: managing property listings across portals

Each of these follows the same principle: the portal has no API, the work is repetitive, authentication is personal, and the data is sensitive. A Side Agent handles the mechanical part while you stay in control.

The same automation-first mindset drives our work on support bots for Benelux businesses and AI-powered appointment booking in Belgium. For a broader look at automation across Belgian business workflows, read our automation guide for Belgian SMEs.

🏁 Getting Started

The best automation is not always the biggest automation. Sometimes the right move is a small, focused tool that sits next to you in the browser and takes over the boring part. That is the Side Agent.

If you deal with Intervat, the extension is ready to use today. If you have a different portal that is eating your time, we build Side Agents for specific workflows.

Talk to us about your workflow