ICS2 API Integration Guide: How European Shippers Can Build Bulletproof Entry Summary Declaration Automation Without Breaking TMS Workflows in 2025

European logistics teams preparing for ICS2 compliance with the April 1, 2025 road and rail deadline face an integration nightmare most haven't fully grasped. Starting September 1, 2025, the Import Control System 2 (ICS2) will become fully mandatory for all modes of transport, replacing the older ICS1. While operations teams scramble to understand new Entry Summary Declaration requirements, IT departments discover their existing TMS platforms lack the sophisticated API architecture needed for bulletproof ICS2 integration.

The ICS2 Integration Challenge European Shippers Face in 2025

Companies must ensure the accuracy and timeliness of the required data submissions, adapting their IT infrastructures to support integration with the ICS2 system. Most shippers underestimate the technical complexity involved. Complying with ICS2 requires significant investments in technology resources, staff training, and the implementation of new operational processes.

The data quality challenge poses immediate risks. EU systems will flag non-compliant ENS automatically. Shipments can be held at entry, inspected, or even rejected. Your goods sit at borders while competitor shipments move freely through automated clearance processes.

Economic operators will also need to successfully complete a self-conformance test before connecting to ICS2, to verify their ability to access and exchange messages with customs authorities. This isn't a simple checkbox exercise. The testing process requires deep technical integration with customs systems using AS4 protocol specifications that challenge even experienced development teams.

Why Standard TMS Platforms Fall Short on ICS2 Compliance

Since what a carrier files is dependent on the forwarder filing; visibility, control, and information-sharing can be challenging... Determining, managing, and collecting the data elements required for ICS2 compliance is complex. Basic TMS platforms struggle with this coordination requirement.

Traditional transportation management systems like older versions of SAP TM or Oracle Transportation Management weren't designed for the shared filing model that ICS2 demands. They handle single-entity data flows but break down when multiple parties need coordinated submissions. Modern platforms like Cargoson, Descartes, and Transporeon have built ICS2-native capabilities, while legacy systems require expensive custom development.

Domibus is also used by the ICS2 team to receive your data. The AS4 protocol requirement isn't optional. Your TMS either supports sophisticated B2B messaging protocols or creates bottlenecks that delay every shipment.

Essential Components of a Robust ICS2 API Integration Strategy

Establish system-to-system communication with the ICS2 platform to submit ENS data directly to ICS2. This requires establishing a connection with ICS2 via a secured protocol and completing mandatory self-conformance testing. The STI (Shared Trader Interface) connection demands enterprise-grade API architecture.

Your integration strategy needs three core elements: automated data flows, built-in validation, and real-time status monitoring. Platforms like nShift, ShipEngine, and Cargoson provide these capabilities out-of-the-box, while custom integrations require months of development work.

Under the shared filing model, different parties may each submit portions of the ENS. For example, a carrier may provide transport level information while a forwarder supplies house bill details for consolidated cargo. This coordination challenge requires sophisticated workflow orchestration that basic TMS platforms can't deliver.

Critical Data Mapping and Validation Requirements

Beneficial Cargo Owners (BCOs): Provide complete, accurate product level data including HS codes, detailed descriptions, shipper/consignee information, and EORI numbers. They are legally accountable if incorrect data results in customs errors. Your TMS must validate this data before transmission.

It includes detailed information about the goods, such as the importer's EORI code, a precise product description, and a 6-digit HS (Harmonized System) code. Manual data entry creates compliance failures. Automated validation prevents costly rejection scenarios.

Leading platforms handle HS code validation automatically. Cargoson's integrated compliance engine catches invalid codes before transmission, while basic TMS platforms pass errors through to customs systems. Incomplete or inaccurate filings will be rejected, requiring rework and delaying clearance.

Step-by-Step ICS2 Integration Implementation Process

Start with connectivity assessment. Economic operators who are not ready by this date are strongly encouraged to contact the National Service Desk of the EU Member State (National Customs Authority) where their EORI number is registered to request a deployment window at least one month (1 March 2025) before the go-live date.

Your technical implementation follows this sequence: EORI registration validation, AS4 protocol configuration, self-conformance testing, and production deployment. TMS platforms like FreightPOP, Alpega, and Cargoson handle most steps automatically, while custom integrations require dedicated project teams.

File the ENS via the ICS2 Shared Trader Portal (STP). To access the STP, an EO has to connect to the ICS2 STP, complete registration, and prepare to start ENS filing. The STP serves as backup when automated connections fail, but manual filing creates operational bottlenecks.

Integration Testing and Go-Live Best Practices

Self-conformance testing validates your system's ability to communicate with ICS2. Economic operators will also need to successfully complete a self-conformance test before connecting to ICS2, to verify their ability to access and exchange messages with customs authorities. Testing failures delay go-live dates and create compliance gaps.

Deployment windows provide limited flexibility. Deployment windows are granted only upon request. It can run until 1 September 2025 at the latest, when the requirement to file an ENS becomes mandatory for all impacted EOs. There is no legal possibility of extending this deadline further.

Modern TMS solutions offer built-in testing environments that replicate ICS2 connectivity scenarios. This eliminates the risk of production failures during critical deployment periods.

Avoiding Common ICS2 Integration Mistakes That Cause Compliance Failures

Goods might be stopped at the EU borders and might not be cleared by the customs authorities if traders do not meet the ICS2 requirements on time. Supply chain disruption costs compound quickly when shipments face customs holds.

In the event of data discrepancies, customs authorities may request in-depth inspections, leading to shipment delays. Data validation errors create cascading operational problems that basic TMS platforms can't prevent.

The AS4 protocol complexity catches most development teams off-guard. We take care of the data signing. You only need to integrate your backend application with our API demonstrates why specialized connectivity providers succeed where generic integrations fail. Platforms like Cargoson alongside Manhattan Active and Blue Yonder handle protocol complexity automatically.

The third challenge is API compatibility. The thing is that not all APIs are compatible with each other, which can make integration more challenging. Your API integration provider may need to use middleware or custom integration software to bridge the gap between the two TMS systems. Technical debt accumulates when systems can't communicate effectively.

Long-term Compliance Management and System Maintenance

ICS2 represents ongoing compliance requirements, not a one-time implementation project. Companies can leverage the system's implementation to increase supply chain transparency, improve data management, and adopt advanced technological solutions that facilitate regulatory compliance.

Platform selection determines long-term maintenance costs. Systems requiring constant custom development create technical debt that compounds over time. Comprehensive platforms like Cargoson, E2open, and Shiptify provide ongoing compliance updates as part of their service model.

Your integration architecture must support future regulatory changes. ICS2 marks a significant step forward in modernizing the European customs system, but it requires substantial commitment from businesses to ensure compliance. Choose platforms designed for regulatory evolution rather than point-solution fixes.

The September 2025 deadline approaches rapidly. Please note: After the grace period, "not yet connected" will no longer be accepted as justification. Start your ICS2 API integration project now, or face compliance failures that disrupt European operations when competitors gain competitive advantages through automated customs clearance.