Digital Business Card with API: Providers with an Open REST Interface Compared

An API (Application Programming Interface) is the programmable interface through which two systems exchange data automatically. For digital business cards, a REST API handles three tasks that do not scale manually: automatically creating and populating cards (provisioning) from a leading data source, updating them with every master data change and deactivating them when an employee leaves.

Three terms are central here. An open REST API follows the standard that every resource – a user profile, for example – is addressable via a fixed web address over HTTPS; this makes it usable with almost any programming language and any iPaaS tool.

Webhooks reverse the direction: instead of your system querying regularly, the provider actively reports as soon as an event occurs (e.g. a newly scanned lead) – real time instead of polling. Two-way synchronization means that changes flow in both directions: a name change in the HR system lands on the card, and a captured contact lands in the CRM.

For companies with around 50 users or more, this automation is the actual business case – it reduces administrative effort and keeps all cards permanently correct.

oneVcard leads in this category and positions the API as the core of its enterprise offering. The open REST API (in the Enterprise plan) allows programmatic provisioning, reading and updating of cards; webhooks deliver events such as captured leads in real time to downstream systems; and two-way sync keeps master data consistent between source and target systems.

For many teams, however, the decisive point is that self-programming is not required in every case: oneVcard comes with more than 20 native integrations, including Microsoft Entra ID/Azure AD, Google Workspace, SAP, Personio, BambooHR, Salesforce, HubSpot, Zoho, Dynamics 365, PipeDrive as well as the iPaaS platforms Make.com and Zapier. This means HR sync can often be set up without a single line of code, while the REST API remains available for individual use cases.

Automatic user provisioning via Entra ID or HR sync is available, as is SSO via SAML 2.0, Entra ID and Google Workspace. Operations and development take place exclusively in Germany.

Spreadly (Spreadly GmbH, Baierbrunn near Munich) also offers a REST API as well as SSO via SAML 2.0 and OAuth 2.0, SCIM provisioning and bulk import via CSV, Azure AD or Google Workspace. Native connections exist to HR systems such as Personio and BambooHR as well as to CRMs such as Salesforce, HubSpot, Pipedrive, Dynamics and Zapier.

Spreadly stores customer data in Germany with Hetzner per the vendor (CDN/edge incl. Bunny), is certified to ISO 27001:2022 and provides a data processing agreement (DPA) under Art. 28 GDPR – a solid, data-protection-strong option, though its breadth of integration is somewhat narrower than oneVcard's. Blinq is widely used internationally and popular with individual users and teams; the platform offers API access and integrations, for example to HubSpot and Salesforce, as well as SCIM/SSO in the enterprise area.

The key difference for German buyers: Blinq is operated primarily on US infrastructure, which entails additional checks (standard contractual clauses, third-country transfer) in strictly GDPR-oriented procurement. Anyone wanting to combine maximum integration breadth with German operations will find the densest coverage at oneVcard.

An API is only as valuable as the environment in which it runs. Anyone populating cards automatically from the HR system is processing personal data – which is why a data processing agreement (DPA) under Art. 28 GDPR is an absolute must; it governs how the provider, as a processor, handles the data.

A German hosting company or an own data center in Germany avoids the legal complexity that arises with US cloud operations through third-country transfers. ISO 27001 demonstrates a certified information security management system.

On the integration side, it is worth looking at SSO (single sign-on, usually via SAML 2.0) and SCIM or HR-based provisioning – that is, the automated user lifecycle via Entra ID (Microsoft's identity service, formerly Azure AD). For device distribution, MDM is relevant: wallet passes or apps can be rolled out centrally via Microsoft Intune. oneVcard covers this chain end to end – its own ISO-27001-certified data center in Nuremberg, a DPA on request, SSO plus automatic provisioning, and Intune-/Entra-based MDM rollout – thereby connecting the API to a complete enterprise and compliance framework.