Despite rapid advances in enterprise software, legacy ERP systems continue to run the core operations of thousands of organizations. This usually means platforms like SAP ECC, SAP S/4HANA, Oracle E-Business Suite, Oracle JD Edwards, Microsoft Dynamics AX, Dynamics 365, Infor, Epicor, or NetSuite, plus plenty of custom-built systems nobody wants to touch.

Today, businesses have invested years, and often millions of dollars, in customizing these platforms to match their unique processes. These systems are responsible for critical functions such as financial management, procurement, inventory management, manufacturing operations, human resources, supply chain management and customer order processing.

For many organizations, replacing these systems simply isn’t practical. A complete ERP migration can take years, require extensive consulting, and introduce significant business risk.

The problem is rarely the ERP system itself.

Instead, the challenge lies in how employees interact with it every day.

Common frustrations include:

• Complex user interfaces that require extensive training.
• Manual approvals managed through emails and spreadsheets.
• Limited mobile accessibility.
• Data scattered across multiple business applications.
• Slow reporting that depends on manual exports.
• Repetitive administrative tasks that reduce productivity.

As a result, employees often create their own workarounds. They export ERP data into spreadsheets, maintain duplicate records, or build disconnected processes outside the ERP. While these fixes solve immediate problems, they also create inconsistencies, increase manual effort, and make business operations harder to manage.

This is exactly why legacy ERP modernization has become a strategic priority for enterprise IT teams. The objective is no longer to replace an ERP system simply because it’s old. Instead, organizations are looking for practical ways to improve user experiences, streamline workflows, and automate routine tasks while keeping the ERP as the trusted system of record.

One increasingly popular approach is to build modern internal applications that sit on top of existing ERP systems. Rather than asking employees to navigate complex ERP interfaces, organizations provide purpose-built applications tailored to specific workflows such as purchase approvals, inventory tracking, employee requests, or operational dashboards.

Platforms like ToolJet make this approach significantly faster by enabling developers to connect to existing ERP databases and APIs, build secure internal applications with minimal effort, and automate business workflows without replacing the underlying ERP. ToolJet is open source (AGPL v3), so teams can inspect, self-host, and extend it under the same governance standards they already apply to their ERP stack.

The shift toward modernizing around the ERP instead of replacing it isn’t happening in isolation. A handful of broader trends have made it the more obvious choice.

• Cloud adoption. Most enterprises have already moved everything else to the cloud, so a monolithic on-prem ERP increasingly looks like the odd one out rather than the foundation.
• Composable architecture. Instead of one system doing everything, teams now assemble best-fit tools around a stable core, and the ERP is a natural candidate for that core.
• The API economy. Modern ERPs, and most legacy ones with a bit of work, expose enough through APIs that building on top of them no longer requires touching the core system at all.
• AI copilots. Natural-language app generation means a purpose-built approval portal or reporting dashboard can go from idea to working app in hours, not sprints.
• Internal developer platforms. Engineering teams already expect self-serve tooling for everything else; ERP-adjacent workflows are catching up to that same expectation.
• Rising replacement costs. Full ERP replacements keep getting more expensive and slower to deliver, which pushes the cost-benefit calculation further in favor of incremental modernization.

None of this makes the ERP itself less important. It just means fewer teams are willing to bet a multi-year project on replacing something that’s still doing its job.

When employees struggle with outdated ERP interfaces or slow business processes, replacing the entire system might seem like the obvious solution.

In reality, it’s often the most expensive and disruptive option.

Modern ERP implementations can take months or even years to complete. Beyond software licensing costs, organizations also need to account for consulting services, data migration, employee training, testing, and ongoing support. Even after a successful migration, teams still need time to adapt to new workflows and processes.

A full ERP replacement often comes with challenges such as:

• High implementation and consulting costs.
• Long deployment timelines.
• Complex data migration projects.
• Business disruption during the transition.
• Employee retraining across multiple departments.
• Risk of losing custom workflows built over many years.
• Integration challenges with existing business applications.

For many organizations, these risks outweigh the potential benefits, especially when the existing ERP continues to manage core business operations reliably.

Instead of replacing their ERP, many enterprises are asking a different question:

“How can we improve the employee experience without rebuilding everything?”

That shift in thinking has changed how organizations approach legacy ERP modernization.

Rather than replacing the ERP, they modernize the layers around it.

For example, instead of asking employees to navigate complex ERP menus, organizations build dedicated applications for everyday tasks such as:

• Purchase request approvals
• Leave and expense management
• Inventory lookups
• Vendor onboarding
• Customer support workflows
• Production monitoring dashboards
• Executive reporting

These applications connect directly to the existing ERP through databases or APIs, allowing employees to complete tasks using modern interfaces while the ERP continues to store and manage business data.

This approach offers several advantages:

Traditional ERP Replacement	ERP Modernization with Internal Applications
Multi-year implementation	Incremental rollout by workflow
High migration costs	Lower development costs
Business disruption	Minimal operational impact
Large-scale retraining	Familiar, task-focused interfaces
Replace existing investment	Extend existing investment
High project risk	Faster time to value

By modernizing one workflow at a time, organizations can deliver improvements much faster while reducing implementation risk. Teams begin seeing measurable productivity gains without waiting years for a complete ERP transformation.

That’s exactly where platforms like ToolJet earn their place. Instead of replacing the ERP, ToolJet helps organizations build secure applications, dashboards, and automated workflows that work alongside existing ERP systems, with far less complexity.

Modernizing a legacy ERP system doesn’t mean replacing the software that already runs your business. More often, it means improving how employees interact with it.

Instead of forcing every department to use the same complex ERP interface, organizations are building purpose-built internal applications for specific business processes. These applications connect directly to the ERP, retrieve the required data, and present it through a cleaner, more intuitive interface.

The ERP continues to serve as the system of record, while employees benefit from applications designed around the way they actually work.

This approach delivers value much faster because organizations can modernize one workflow at a time instead of attempting a large-scale transformation project.

Here are some of the most common ways enterprises extend their legacy ERP systems.

Procurement teams often spend valuable time navigating multiple ERP screens just to approve purchase requests or verify budgets.

A modern approval application can simplify this process by providing:

• A single dashboard for pending approvals.
• One-click approve or reject actions.
• Budget visibility before approval.
• Automated notifications and reminders.
• Complete approval history for auditing.

Instead of logging into the ERP for every approval, managers receive a streamlined interface focused only on the decisions they need to make.

Warehouse staff rarely need access to every feature inside an ERP system. They typically require quick access to inventory levels, stock movements, purchase orders, and shipment updates.

An internal inventory application can provide:

• Real-time inventory availability.
• Barcode or QR code support.
• Warehouse-specific dashboards.
• Faster product searches.
• Mobile-friendly interfaces for warehouse teams.

This reduces the time spent navigating ERP menus while helping teams make faster operational decisions.

Many HR requests still involve multiple emails, spreadsheets, or support tickets before reaching the ERP.

Instead, organizations can build employee self-service portals where staff can:

• Submit leave requests.
• Update personal information.
• Track reimbursement requests.
• View payroll documents.
• Raise HR service requests.
• Monitor approval status in real time.

Employees enjoy a much simpler experience, while HR teams spend less time handling repetitive administrative work.

Finance teams frequently export ERP data into spreadsheets to create reports for leadership.

Modern dashboards eliminate much of this manual effort by displaying live business metrics such as:

• Revenue trends.
• Outstanding invoices.
• Cash flow summaries.
• Purchase order status.
• Budget utilization.
• Department-level spending.

Executives gain real-time visibility without waiting for manually prepared reports.

Operational processes rarely exist entirely within an ERP. Teams often rely on email, spreadsheets, chat platforms, and separate databases to complete everyday work.

Internal applications can bring these processes together by automating workflows such as:

• Vendor onboarding.
• Asset management.
• Equipment maintenance.
• Quality inspections.
• Incident reporting.
• Compliance tracking.

Instead of switching between multiple tools, employees complete the entire workflow from a single application while the ERP remains synchronized in the background.

The biggest advantage of this approach is flexibility.

Organizations don’t have to modernize everything at once. They can start with one high-impact workflow, measure improvements, gather employee feedback, and gradually expand to other departments. This incremental strategy reduces project risk while delivering business value much sooner than a full ERP replacement.

This is where ToolJet fits naturally into an ERP modernization strategy. ToolJet enables development teams to quickly build secure internal applications that connect to existing ERP databases and APIs. With pre-built connectors, reusable UI components, workflow automation, and enterprise-grade deployment options, organizations can deliver modern experiences without disrupting the ERP systems they already rely on.

By treating the ERP as the foundation rather than the user interface, enterprises can extend the value of their existing investment while giving employees faster, simpler, and more productive ways to work.

Modern ERP does not require replacing the existing ERP system. Instead, organizations can introduce a modern application layer on top of their existing ERP infrastructure.

In this approach, the ERP remains the system of record responsible for managing critical business data such as finance, inventory, procurement, and employee information. ToolJet connects to SAP HANA and Oracle databases directly.  ToolJet also connects to ERP system that exposes REST or GraphQL,  which covers SAP, Oracle-based systems, Dynamics, NetSuite, and custom-built ERPs without requiring a dedicated integration for each vendor.

The architecture typically consists of three layers:

1. ERP Data Layer
The existing ERP system, databases, and APIs continue storing and managing core business information. No major data migration is required.

2. Application Layer With ToolJet
ToolJet acts as the internal application layer where teams build dashboards, approval workflows, portals, and operational applications connected to ERP data.

3. User Experience Layer
Employees interact with purpose-built applications designed around their workflows instead of navigating complex ERP interfaces.

This approach allows organizations to modernize specific business processes incrementally. Teams can start with high-impact workflows such as purchase approvals, inventory tracking, or reporting dashboards while keeping the ERP as the trusted source of business data.

​​Real Results from ToolJet Customers

Every enterprise’s legacy stack looks different, but the underlying pattern holds: modernizing around old systems, instead of replacing them, delivers results fast. Here’s what that’s looked like across industries for real ToolJet customers extending their own legacy environments.

Company	Industry	What They Modernized	Outcome
Pizza Pizza	Food & Beverage, 750+ locations	Replaced legacy internal tooling with 6 apps connected to 20+ existing data sources	50% faster development, 30% lower dev costs, 500+ hours saved
FrankieOne	Fintech, identity verification	Replaced legacy Vue.js internal tooling without adding frontend engineers	6+ apps built, dev cycles cut from days to hours
FalconX	Institutional crypto trading	Built internal ops tools on top of existing microservices, no frontend team needed	85% less development time, 15 developer days saved per app
Emeritus	EdTech, 1,000+ employees	Replaced disconnected internal systems (BigQuery, Salesforce, Canvas, Zendesk) with unified tools	50% faster development, 40% lower dev costs, 600+ hours saved
Toss	Financial services	Built 300+ internal apps and admin dashboards across 6 departments over 3 years	100+ apps actively in use, ~10 frontend devs’ worth of effort saved
BFKN	Legal services	Replaced a legacy Access database with 5 connected apps for case, time, and document management	25% fewer data entry errors, 40% faster document search, 50% faster reimbursements
VSO	Hybrid-cloud service management	Replaced Tableau and custom React reporting tools with 15 ToolJet applications	15 apps live in 1-2 months, substantial cost savings over Tableau
Infear.org	Non-profit, child welfare	Replaced unstable legacy tooling with 7 apps connected to MySQL across 9 data sources	60+ days saved on updates, 3-hour team onboarding
RevQ	Quick commerce	Automated a fully manual client onboarding process	95% reduction in onboarding time, results in 3 months
Byju’s	EdTech, offline learning centers	Built batch scheduling and reporting tools connected to Snowflake and Google Sheets across 20 sources	500+ hours saved, 60% faster batch scheduling, 40% fewer errors
MGID	Ad-tech	Replaced manual database and partner API workflows with 20 self-service apps	4x user base growth, 85% dev and maintenance time saved
Nimbl	Accounting, financial services	Replaced Microsoft Power Apps for client management and HR workflows	70% faster development, 78% cost reduction vs. Power Apps

The takeaway isn’t that all of these companies had an ERP specifically. BFKN’s legacy Access database and Infear.org’s unstable legacy stack are the closest parallels, but the pattern is the same everywhere on this list: connect to what already exists instead of ripping it out, and the payoff shows up in weeks, not years.

Once you know which workflows need fixing, the next question is simple: what do you build them with?

Traditional application development often requires multiple frameworks, backend services, UI libraries, authentication systems, and months of engineering effort. For many internal business applications, that level of complexity isn’t necessary.

ToolJet provides a faster way to build enterprise-grade internal applications that integrate with your existing ERP system, helping development teams modernize workflows without rebuilding the ERP itself.

Here’s how ToolJet simplifies legacy ERP modernization.

Most ERP systems already expose data through databases, APIs, or web services. ToolJet connects to these existing data sources, allowing developers to build applications without duplicating business data.

You can integrate with:

• PostgreSQL
• MySQL
• Microsoft SQL Server
• Oracle Database
• REST APIs
• GraphQL APIs

This means your ERP remains the single source of truth while ToolJet handles the user experience.

Not every employee needs full access to your ERP.

With ToolJet’s app templates, teams can quickly create applications designed around specific business tasks, such as:

• Purchase approval portals
• Inventory management dashboards
• Vendor onboarding applications
• Finance reporting dashboards
• HR self-service portals
• Customer support consoles

These focused applications reduce complexity, shorten training time, and help employees complete tasks more efficiently.

Many ERP-related tasks still involve manual approvals, follow-up emails, and repetitive administrative work.

ToolJet’s workflow automation capabilities help teams streamline these processes by enabling:

• Multi-level approval workflows
• Scheduled jobs
• Email and Slack notifications
• Database updates
• API calls to external systems
• Event-driven automations

Instead of managing repetitive tasks manually, organizations can automate routine business operations while keeping ERP records synchronized.

Building internal applications doesn’t have to start from scratch.

With ToolJet AI, developers can generate application layouts, forms, tables, and CRUD interfaces using natural language prompts. Teams can then customize these generated components to match their business requirements.

This significantly reduces development time, allowing organizations to deliver modernization projects in days or weeks instead of months.

ERP systems often contain sensitive financial, operational, and employee data. Security and compliance are therefore critical considerations for any modernization project.

ToolJet is designed for enterprise deployments with capabilities such as:

• Self-hosted deployment options
• Role-Based Access Control (RBAC)
• Single Sign-On (SSO)
• Audit logs
• Environment management
• GitSync for collaborative development

ToolJet’s enterprise plans also align with SOC 2 and support the compliance requirements of regulated industries handling sensitive ERP data. These features help organizations maintain governance and security while extending their ERP with modern applications.

The biggest advantage of using ToolJet is that modernization becomes incremental instead of disruptive.

Rather than replacing an entire ERP platform, development teams can deliver one application, automate one workflow, or improve one department at a time. Each successful project builds momentum for the next, allowing organizations to modernize continuously while preserving the stability and business logic of their existing ERP systems.

This phased approach not only reduces implementation risk but also helps enterprises realize value much sooner, making legacy ERP modernization a practical, measurable initiative instead of a multi-year transformation program.