What Defines a RAIN System, And Why It’s Not Negotiable

At its core, a RAIN system is a standards-based wireless system where both the tag and the reader implement the RAIN air-interface protocol (ISO/IEC 18000-63, also known as GS1 UHF Gen2) and the tag is encoded with an identifier that is guaranteed to be globally unique.

Both elements are essential. If either is missing, the system may use RAIN RFID technology, but it is not truly a RAIN RFID system.

Why is this so important? Because the consequences of non-unique identifiers are real and costly. Organizations may implement RAIN systems with tens of millions of tags, significant investment, and everything is working smoothly. Until two years later, they discover that their identifiers conflict with tags from a supplier, a merger, or even their own second facility. The result: chaos in databases, failed reads, and massive remediation projects that could have been prevented with a single decision at the start.

These conflicts happen more often than most organizations realize, and they all trace back to the same root cause: identifiers that aren’t guaranteed to be globally unique.

Why Global Uniqueness Isn’t Optional

The requirement for globally unique, standards-based encoding isn’t bureaucratic overhead. It’s the fundamental architecture that allows RAIN systems to scale, interoperate, and deliver long-term value.

Here’s what many organizations miss: Non-unique identifiers don’t just fail when someone deliberately builds a “closed system.” Real-world data from GS1 reveals that encoding problems also emerge from process failures—a miscommunication during a partner handoff, incorrect assumptions made during implementation, undocumented shortcuts taken under time pressure. By the time the issue surfaces, tags are already in circulation, and fixing it becomes exponentially more complex and costly.

This is why end users must explicitly mandate standards-based, globally unique encoding as a non-negotiable requirement. Not as a nice-to-have. Not as “we’ll worry about it later.” As a foundational specification from day one.

Why Standards Matter

Standards exist to ensure trust at scale. Consider if there were a risk that your credit card number was not unique. Or your bank account number. Or even your phone number. The systems behind payments, communications, and identity only work because every identifier is guaranteed to belong to one, and only one entity, anywhere in the world. RAIN technology, operates on the same principle.

As the Center for Strategic and International Studies (CSIS) aptly puts it: “Standards are indispensable to innovation, providing shared platforms for industry participants to work together to bring new technological solutions to the marketplace.”1

This principle continues to drive innovation across industries. Major technology and retail companies—Google, Amazon, Walmart, and OpenAI—are all releasing new open standards for AI-powered commerce. Google’s recently announced Universal Commerce Protocol (UCP), co-developed with major retailers including Shopify, Target, and Walmart, enables all agents and systems to interact easily rather than requiring unique connections for every platform. It’s another example of how open standards unlock innovation and enable entire ecosystems to grow together.

Standards ensure that identifiers remain unique, systems remain interoperable, and deployments can scale confidently—across facilities, organizations, industries, and borders.

Standards Enable Scaling Across Industries

Look around at the technologies that have transformed our world. Wi-Fi didn’t become ubiquitous by accident, it succeeded because devices from different manufacturers could seamlessly connect to any router. Bluetooth became the universal language for wireless device communication because everyone followed the same standard. USB ports work with any compatible device because standards ensure interoperability.

RAIN technology is following this same proven path. The RAIN RFID market is experiencing explosive growth:

  • RAIN technology currently tracks $1.7 billion worth of items globally
  • 22% annual tag shipment growth forecast for RAIN tags and labels2
  • More than 100 billion tag chips projected to ship in 20282
  • Over $1 billion in revenues for tag ICs expected in 20282

This remarkable growth is driven by diverse applications across retail, healthcare, logistics, manufacturing, aviation, aerospace, energy, local government, and military sectors. But such diverse solutions and markets require a solid, standards-based foundation.

The Two Fundamental Numbering Systems

RAIN RFID supports two fundamental numbering systems for encoding tags to ensure global uniqueness—one specified by GS1 and the other specified by ISO.

1. GS1 Numbering System (GS1 EPC Tag Data Standard)

The GS1 system leverages globally recognized numbering schemes that have powered supply chains for decades. Through the GS1 EPC Tag Data Standard (TDS), organizations can encode their tags using:

  • EPC (Electronic Product Code) schemes that extend familiar barcodes like GTINs, SSCCs, and GLNs into the RAIN RFID world
  • Company prefixes assigned by GS1 that ensure no two organizations will ever use the same identifiers
  • Proven governance structures that have maintained data integrity across millions of companies worldwide

GS1 encoding is particularly valuable for supply chain applications and offers seamless integration with barcode systems used in retail, logistics, and many other industries.

2. ISO Numbering System

The ISO numbering system provides alternative paths to guaranteed global uniqueness. These include:

  • Industry-specific ISO numbering systems like IATA standards for aviation and VDA standards for automotive
  • RAIN Alliance-managed ISO encoding schemes including:
    • RAIN Alliance-Issued CIN with Free-Form Encoding Schemes
    • RAIN URI Identifier
    • RAIN Free-Form Encoding Schemes
  • Other ISO-compliant numbering schemes registered in the Data Constructs Register
  • Controlled allocation through authorized issuing agencies to prevent conflicts

The RAIN Alliance serves as an ISO-authorized issuing agency and developed multiple ISO encoding schemes to provide flexible options for organizations implementing RAIN technology with the same guarantee of global uniqueness that GS1 provides.

For complete technical details on encoding schemes and best practices, see the RAIN Alliance Tag Encoding Guide and Specifications.

Why Non-Standard Approaches Fail

Some vendors or implementers might be tempted to create their own numbering schemes. Perhaps they want to minimize costs, or they believe their closed system doesn’t need global uniqueness. This approach is fundamentally flawed and we strongly advise against it for these reasons:

Loss of Interoperability and Scalability

Custom numbering schemes create data silos. When tags from different systems meet—whether through supply chain partnerships, mergers, acquisitions, or secondary markets—conflicts become inevitable. Two companies might unknowingly use the same identifier for completely different items, creating confusion in shared databases and supply chains.

A closed system might work fine within your four walls today. But what happens when you expand to new facilities? Enter new markets? Partner with new suppliers or customers? Or when a consumer walks into your store wearing tagged apparel from another retailer? Without globally unique identifiers, your RAIN system could misread their items as your inventory, triggering false positives and creating operational chaos.

RAIN technology’s power comes from its universality. Just as the internet works because everyone follows TCP/IP, RAIN technology delivers value because everyone follows the same standards.

Future-Proofing Failures

Standards evolve to meet new requirements and address emerging use cases. Organizations using non-standard encoding schemes are left behind, unable to take advantage of new capabilities and improvements that the ecosystem develops.

Compliance and Regulatory Risks

Increasingly, regulations explicitly require standards-based approaches. The EU’s Digital Product Passport (DPP), mandatory for many products starting in 2027, requires ISO/IEC 15459:2015 compliance and globally unique identifiers created in accordance with standards like GS1 or ISO. Non-standard encoding means non-compliance and potential market exclusion.

Similar regulatory frameworks are emerging globally, all built on standards-based identification: pharmaceutical serialization under the US Drug Supply Chain Security Act (DSCSA) and EU Falsified Medicines Directive (FMD) requires GS1 standards for prescription drugs, while the EU Battery Regulation mandates ISO 15459-compliant identifiers for EV and industrial batteries starting in 2027. Custom schemes create compliance risks across customer requirements, industry mandates, and regulatory frameworks.

The Global Uniqueness Guarantee

The fundamental requirement is simple: every RAIN tag must have an identifier that is globally unique—meaning no other tag, anywhere in the world, now or in the future, will have the same identifier.

This seems like a basic requirement, but achieving it at scale requires reliable governance:

  • Centralized allocation of company prefixes or identification numbers
  • Clear rules for how organizations structure identifiers within their allocated space
  • Ongoing management to prevent conflicts and address edge cases
  • Transparent documentation so everyone understands the system

Both GS1 and the ISO/RAIN Alliance numbering systems provide these governance structures. Custom schemes cannot, almost by definition.

The Path Forward

If you’re implementing RAIN technology—whether you’re a solution provider, end-user, or systems integrator—the path is clear:

  • Commit to standards-based encoding across your ecosystem:
    • Verify that partners and vendors are using standards-based encoding
    • Include standards compliance in your requirements and contracts
    • Educate stakeholders on why this matters
  • Choose your standards-based numbering system:
    • Use GS1 EPC TDS
    • OR use an ISO encoding scheme such as:
      • Industry-specific ISO standards (IATA for aviation, VDA for automotive)
      • RAIN Alliance-managed ISO encoding schemes (including RAIN CIN)
      • Other applicable ISO-compliant numbering schemes
  • Think long-term:
    • Don’t let short-term cost considerations drive you toward proprietary schemes
    • Remember that the value of RAIN RFID compounds over time as more participants join the ecosystem
    • Standards-based approaches are an investment in future flexibility and scalability

Conclusion: Standards Are Not Optional

In the RAIN ecosystem, standards-based encoding isn’t a nice-to-have feature or a checkbox to satisfy purchasing departments. It’s a fundamental requirement that defines whether what you’ve implemented is truly a RAIN system or just UHF RFID technology that happens to use the same air interface.

The growth trajectory of RAIN technology—toward hundreds of billions of tags creating visibility into trillions of everyday items—is only possible because the industry has committed to standards. Every organization that chooses a non-standard path doesn’t just limit their own potential; they create friction for the entire ecosystem.

The choice is yours: you can build on the solid foundation of globally recognized standards—either GS1 or ISO/RAIN Alliance numbering—or you can create a system that might work in isolation but sooner or later will become a choke point for your company’s growth.

Choose standards. Choose interoperability. Choose scalability. Choose RAIN—the real thing, with standards-based encoding that guarantees global uniqueness.

Because if it doesn’t have standards-based, globally unique encoding, it’s simply not a RAIN system.

References
  1. Center for Strategic and International Studies (CSIS), as cited in “The Importance of Standardized Solutions for RAIN Deployments,” RAIN Alliance presentation, RFID Journal Live 2025.
  2. RAIN market projections from, ABI Research, UHF RFID Technologies, Applications, and End Markets, 1Q 2025