1. Introduction

1.1. Problem Statement: lack of interoperability in identity systems

Target 16.9 of the UN Sustainable Development Goals is to “provide legal identity for all, including birth registration” by the year 2030. But there is a major barrier: the lack of vendor/provider and technology neutrality - commonly known as “vendor lock-in”.

The lack of vendor and technology neutrality and its consequences becomes apparent when a customer needs to replace one building block of the identity management solution with one from another provider, or expand the scope of their solution by linking to new building blocks. Main technology barriers are the following:

  1. Solution architectures are not interoperable by design. The lack of common definitions as to the overall scope of an identity ecosystem, as well as in the main functionalities of a system’s building blocks (civil registry, biometric identification system, population registry etc.), blurs the lines between building blocks and leads to inconsistencies. This lack of so-called irreducibly modular architectures makes it difficult, if not impossible, to switch to a third-party building block intended to provide the same function and leads to incompatibilities when adding a new building block to an existing ecosystem.

  2. Standardized interfaces (APIs) do not exist. Building blocks are often unable to communicate with each other due to varying interfaces (APIs) and data formats, making it difficult to swap out building blocks or add new ones to the system.

For government policy makers tasked with implementing national identification systems, vendor lock-in is now one of their biggest concerns.


Fig. 1.1 The dependency challenge

1.2. The OSIA Initiative

Launched by the not-for-profit Secure Identity Alliance, Open Standard Identity APIs (OSIA) is an initiative created for the public good to address vendor lock-in problem.

OSIA addresses the vendor lock-in concern by providing a simple, open standards-based connectivity layer between all key building blocks within the national identity ecosystem.

OSIA scope is as follows:

  1. Build a common understanding of the functional scope for identity systems building blocks - NON PRESCRIPTIVE

    OSIA’s first step has been to formalize the definitions, scope, and main functionalities of each building block within the identity management system.

  2. Create a set of standardized interfaces and data dictionary - PRESCRIPTIVE

    For this core piece of work, OSIA is focused on developing the set of interfaces and standardized data dictionary needed to connect the multiple identity system building blocks and ensure seamless interactions via pre-defined services.

    It is then down to each government to define and implement the interaction processes between individual building blocks (which in turn determines which interfaces are associated with each building block), according to local laws and regulations.

With OSIA, governments are free to select the building blocks they need, from the suppliers they choose - without fear of lock in.

And because OSIA operates at the interface layer, interoperability is assured without the need to rearchitect environments or rebuild solutions from the ground up. ID ecosystem building blocks are simply swapped in and out as the use case demands - from best-of-breed options already available on the market.

This real-world approach dramatically reduces operational and financial risk, increases the effectiveness of existing identity ecosystems, and rapidly moves government initiatives from proof of concept to live environments.

1.3. OSIA Benefits

The OSIA initiative offers a wide range of benefits to implementers of national ID management solutions.

  1. Unleash market innovation

    OSIA establishes the conditions that support an equal marketplace and makes it possible for the wider identity community to collaborate in new ways.

    • Create a marketplace where all vendors can compete equally: OSIA operates at the interface layer and does not define - or therefore favor - any technology at the building block layer (which is typically where the differentiation among vendors takes place).

    • Support the emergence of new local market models featuring local suppliers and SMEs: Like the Open Banking revolution, OSIA exposes high performing standardized interfaces that enable new use cases and market offers - from the simple to the complex.

    • Ensure product(s) compatibility after Mergers & Acquisitions: Market consolidation can often lead to major products being put into maintenance - leaving governments with little choice but to replace these. With OSIA, whatever the status of a product, it will continue to be interoperable with new offers.

  2. Enable identity as a service

    OSIA empowers governments to build new inclusive eGovernment solutions that give citizens ease of access to public services or trusted digital ID schemes that extend the use of citizen ID into other online areas - such as banking and payments.

    • Driving digital ID market growth: OSIA facilitates the link between sovereign identity management solutions and digital identity solutions, like mobile ID, by standardizing the ad hoc interfaces that decouple providers of the ID management solution and the digital ID solution.

    • Reducing fraud within siloed databases/multiple ID systems: OSIA enables the secure and controlled flow of data and services, like ID deduplication and authentication, across multiple foundational and functional registries - even where these registries are run by separate ministries and government agencies.

    Governments are able to reduce public sector payroll fraud, leakage in social benefits, fraud associated with tax filing and ensure the integrity of the electoral process.

  3. Address integrator/vendor lock-in

    OSIA enables governments to exert full control over their sovereign identity systems. So, they can pursue their national development agendas - without any fear of integrator/ vendor lock-in. Governments are no longer forced to implement a wall-to-wall solution from a single vendor and will not encounter compatibility difficulties when evolving their existing legacy solutions. They can:

    • Implement multi-vendor programs by mixing selected building blocks from different suppliers.

    • Extend legacy solutions or replace legacy building blocks(s) with a new building block(s) from a different supplier(s).

1.4. Diffusion, Audience, and Access

This specification is hosted in GitHub and can be downloaded from ReadTheDocs.

This specification is licensed under The SIA License.

Any country, technology partner or individual is free to download the functional and technical specifications to implement it in their customized foundational and sectoral ID systems or building blocks. Governments can also reference OSIA as Open Standards in tenders.Any country, technology partner or individual is free to download the functional and technical specifications to implement it in their customized foundational and sectoral ID systems or building blocks. Governments can also reference OSIA as Open Standards in tenders.

For more information on how to reference OSIA please see Section OSIA Versions & Referencing.

1.5. Document Overview

This document aims at:

  • formalizing definitions, scope and main functionalities of each building block within the identity ecosystem,

  • defining standardized interfaces and data format to connect the multiple ecosystem building blocks to ensure seamless interaction via pre-defined services.

This document is structured as follows:

  • Chapter 1 Introduction: This chapter introduces the problem statement and the OSIA initiative.

  • Chapter 2 Functional View: This chapter provides an overview of OSIA interfaces and how they can be mapped against the various identity ecosystem building blocks. Finally, the chapter describes a series of use cases where different OSIA interfaces are implemented between multiple identity ecosystem building blocks.

  • Chapter 3 Security & Privacy: This chapter lists a set of Privacy and Security features embedded in OSIA interfaces specifications.

  • Chapter 4 OSIA Versions & Referencing: This chapter describes the way OSIA interfaces can be referenced in documents and tenders.

  • Chapter 5 Interfaces: This chapter describes the specifications of all OSIA interfaces.

  • Chapter 6 Building Blocks: This chapter describes OSIA interfaces that each building block of the identity ecosystem may implement.

  • Chapter 7 Technical Specifications: This chapter describes the technical specifications for all OSIA interfaces.

  • Chapter 8 Annexes: This chapter describes the glossary, data format and license that covers OSIA specifications.

1.6. Convention and Typographical Rules

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119.

Code samples highlighted in blocks appear like that:

    "key": "value",
    "another_key": 23


Indicates supplementary explanations and useful tips.


Indicates that the specific condition or procedure must be respected.

1.7. Revision History

See OSIA Versions & Referencing.