Introduction
nexo standards is a not-for-profit standards association developing open ISO 20022-based specifications for payment acceptance. Founded in 2014 and based in Brussels, it works to make communication between merchants, terminals, acquirers, processors, PSPs, schemes and payment vendors more interoperable. Its protocols help reduce dependence on proprietary payment interfaces and support more consistent payment acceptance across markets.
What is nexo standards and what does it do
nexo standards develops open messaging protocols and implementation specifications for the payment acceptance ecosystem. Its work focuses on the communication flows between point-of-sale systems, payment terminals, acquirer hosts, terminal management systems and other payment acceptance infrastructure.
The organisation is relevant to all stakeholders involved in card and digital payment acceptance. This includes merchants, acquirers, PSPs, processors, card schemes, terminal vendors, software providers, certification bodies, payment gateways and infrastructure companies.
Mission and remit
nexo standards aims to remove fragmentation from payment acceptance by replacing proprietary interfaces with common, open and interoperable standards. Its specifications are based on ISO 20022 principles, which gives payment stakeholders a shared business vocabulary and message structure.
Its remit is technical and industry-led. nexo standards does not regulate payment firms or impose legal obligations. Instead, it publishes protocols, implementation specifications and testing resources that companies can adopt voluntarily to simplify integration, improve interoperability and reduce the cost of supporting multiple proprietary formats.
Core work domains
- Payment acceptance messaging — ISO 20022-based messages for communication between payment acceptance stakeholders.
- Retailer-to-terminal communication — Protocols that support interaction between point-of-sale systems and payment terminals.
- Terminal-to-acquirer communication — Acquirer protocols that standardise the exchange of payment transaction data with acquiring hosts.
- Terminal management — TMS standards for managing payment terminals through open, non-proprietary interfaces.
- Fast payment acceptance specifications — nexo FAST and related specifications supporting payment acceptance flows and interoperability.
- Implementation specifications — Guidance on how payment acceptance solutions should implement nexo protocols in practical environments.
- Testing and certification support — Test tools, implementation specifications and certification-oriented processes that help adopters validate interoperability.
Geographic scope and cross-border reach
nexo standards is international in scope. Its specifications are designed to be universal and open, allowing payment acceptance stakeholders in different countries to use common protocols instead of building market-by-market proprietary interfaces.
The standards are especially useful for merchants, acquirers, PSPs and terminal providers operating across multiple jurisdictions. Cross-border retailers and global PSPs can use nexo specifications to simplify payment acceptance architecture, reduce integration complexity and make terminal or acquirer changes less dependent on proprietary formats.
Why nexo standards matters for payments operators
nexo standards matters for PSPs, acquirers, processors, payment gateways, terminal vendors, payment orchestration providers and large merchants because it standardises core acceptance flows. Instead of maintaining multiple custom integrations between retailers, terminals and acquirer hosts, operators can adopt common protocols that improve interoperability.
For payment operators, nexo is especially relevant where products involve in-store payments, multi-acquirer setups, point-of-sale integration, payment terminal management, cross-border retail estates, certification, loyalty services, reconciliation, routing and payment infrastructure modernisation. Its standards can reduce integration cost, shorten time to market and make payment acceptance systems easier to scale.
The teams most likely to follow nexo standards include product, engineering, terminal management, acquiring operations, certification, integration, architecture, compliance, partnerships, merchant services and payment operations teams.
Who runs nexo standards and how is it organised
nexo standards operates as an open, not-for-profit member association. Its members represent different parts of the payment acceptance chain, including merchants and payment acceptors, processors, card schemes, PSPs and vendors.
The association is governed through member participation, technical working activity and collaborative standards development. Its outputs are developed for industry adoption rather than regulatory enforcement.
Membership composition
nexo standards’ membership is best described by role in the payment acceptance ecosystem rather than by a single category of institutions.
| Category | Typical participants |
|---|---|
| Merchants and payment acceptors | Retailers, hospitality groups, transport operators and other organisations accepting payments at scale |
| Acquirers and processors | Acquiring banks, processors and host platforms connected to merchant payment acceptance |
| PSPs and gateways | Payment service providers, gateways and orchestration platforms supporting merchant acceptance |
| Card schemes and payment networks | Scheme and network participants interested in interoperable acceptance standards |
| Terminal and POI vendors | Providers of payment terminals, point-of-interaction devices and related software |
| Software and technology vendors | POS providers, terminal management vendors, certification providers and payment infrastructure companies |
| Certification and testing participants | Organisations involved in validating implementations and supporting interoperability |
Working groups and decision-making
nexo standards develops specifications through member-led technical collaboration. Working groups and expert contributors focus on protocol development, implementation specifications, testing, certification, maintenance and evolution of the standards.
Members can participate in standards development, technical discussions and association governance. Non-members may still access public information and evaluate whether nexo standards fit their architecture or certification needs.
What standards does nexo standards publish and how are they used
nexo standards publishes specifications and implementation resources for payment acceptance infrastructure.
| Standard or resource | Scope | Used by |
|---|---|---|
| nexo Retailer Protocol | Communication between retailer systems and payment terminals | Merchants, POS providers, terminal vendors and PSPs |
| nexo Acquirer Protocol | Communication between payment acceptance systems and acquirer hosts | Acquirers, processors, PSPs and payment gateways |
| nexo TMS Protocol | Terminal management through open, non-proprietary messaging | Terminal managers, acquirers, PSPs and vendors |
| nexo FAST | ISO 20022-based payment acceptance specifications | Payment acceptance stakeholders and infrastructure providers |
| nexo Implementation Specifications | Practical guidance for implementing nexo protocols | Engineering, certification and integration teams |
| Test tools and certification resources | Validation of protocol implementation and interoperability | Vendors, PSPs, acquirers, certification bodies and merchants |
Adoption and downstream use
nexo standards adoption is voluntary. Its value comes from interoperability: when multiple stakeholders use the same protocols, merchants and payment operators can reduce proprietary integrations and improve consistency across devices, hosts and markets.
The standards are especially relevant in environments with multiple acquirers, terminal estates, cross-border merchants or complex point-of-sale architectures. They may also support future payment acceptance use cases, including work related to digital euro acceptance and broader ISO 20022-based payment frameworks.
Events and convenings
nexo standards is not mainly known for a large public flagship conference. Its most important activity is standards development, member collaboration, technical work, publication of specifications, implementation support and industry engagement around payment acceptance interoperability.
For payment operators, the key updates to monitor are new protocol versions, implementation specification updates, certification resources and industry announcements about adoption or new payment use cases.
How to engage with nexo standards
Companies can engage with nexo standards by joining the association, reviewing specifications, participating in technical work, using implementation resources or adopting nexo protocols in payment acceptance projects.
The practical route depends on the company’s role. A merchant may evaluate nexo to reduce proprietary terminal integrations; an acquirer may use it to standardise host communication; a PSP or gateway may use it to simplify multi-market acceptance; and a vendor may use it to support interoperable terminal or POS products.
Membership routes and fees
nexo standards offers member participation for organisations involved in payment acceptance. Membership can provide access to working groups, specifications, governance participation and technical collaboration.
Companies should confirm current membership categories, fees, specification access, voting rights and certification-related requirements directly with nexo standards before budgeting for participation.
What participants gain
Participants may gain access to technical specifications, implementation guidance, collaboration with other payment stakeholders, testing resources, certification pathways and influence over future standards development.
The main benefit is practical interoperability: fewer proprietary interfaces, easier integration, more portable acceptance infrastructure and a clearer technical framework for payment acceptance projects.
FAQ
Is nexo standards only for card payments?
nexo standards originated in the card payment acceptance ecosystem, but its ISO 20022-based approach is relevant to broader payment acceptance flows. It is most commonly associated with card and in-store acceptance infrastructure, but its framework can also support newer acceptance models and digital payment use cases.
What problem does nexo standards solve?
nexo standards addresses fragmentation in payment acceptance. Without common protocols, merchants, acquirers, PSPs and terminal vendors often need multiple proprietary integrations. nexo provides shared specifications that make systems easier to connect, maintain and scale across markets.
What is the nexo Retailer Protocol?
The nexo Retailer Protocol standardises communication between a retailer’s point-of-sale system and the payment terminal or point-of-interaction environment. It helps merchants reduce supplier lock-in and create more consistent payment flows across terminals and acquirers.
What is the nexo Acquirer Protocol?
The nexo Acquirer Protocol standardises communication between payment acceptance systems and acquirer hosts. It is useful for acquirers, processors, PSPs and gateways that want common message structures for authorisation, transaction handling and related acquiring flows.
What is the nexo TMS Protocol?
The nexo TMS Protocol supports terminal management through an open and non-proprietary standard. It helps organisations manage payment terminals without being locked into a single supplier’s proprietary terminal management interface.
Does nexo standards provide certification?
nexo standards supports testing and certification through implementation specifications, test tools and certification-oriented processes. Companies adopting nexo protocols should confirm the relevant certification route, test requirements and approved tools for their specific implementation.
Is nexo standards connected to ISO 20022?
Yes. nexo standards specifications and messaging protocols are based on ISO 20022. This gives payment acceptance stakeholders a common vocabulary and message structure that supports interoperability, future maintenance and alignment with broader financial messaging practices.
Is nexo standards mandatory?
No. nexo standards is not a regulator and its specifications are not mandatory by law. Adoption is voluntary, but payment stakeholders may choose nexo to reduce integration complexity, support multi-acquirer environments and improve interoperability across payment acceptance systems.
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