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: the automatic creation and population of cards (provisioning) from a leading data source, updating on every master data change, and deactivation when an employee leaves.

Three terms are central here. An open REST API follows the standard that every resource, such as a user profile, 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 asking regularly, the provider actively reports as soon as an event occurs (e.g. a new scanned lead), real time instead of polling. Two-way synchronization means that changes flow in both directions: a name change in the HR system ends up on the card, a captured contact ends up in the CRM.

For companies from around 50 users onwards, this automation is the real 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) enables programmatic provisioning, reading and updating of cards; webhooks deliver events such as captured leads in real time to downstream systems; via two-way sync, master data stays consistent between the source and target system.

What is decisive for many teams, however, is that you do not necessarily have to program anything yourself 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 the HR sync can often be set up without a single line of code, while the REST API remains open 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. Operation and development take place exclusively in Germany.

Spreadly (Spreadly GmbH, Baierbrunn near München) likewise 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.

According to the provider, Spreadly stores customer data in Germany with Hetzner (CDN/Edge including Bunny), is certified to ISO 27001:2022 and provides a DPA, a solid, privacy-strong option whose breadth of integration, however, is somewhat narrower than that of oneVcard. Blinq is widely used internationally and popular with individual users and teams; the platform offers API access and integrations such as to HubSpot and Salesforce as well as SCIM/SSO in the enterprise segment.

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 who wants to combine maximum breadth of integration with German operation will find the densest coverage at oneVcard.

An API is only as valuable as the environment in which it runs. Anyone who populates cards automatically from the HR system processes personal data, so a DPA under Art. 28 GDPR (data processing agreement) is mandatory; it governs how the provider, as a data processor, handles the data.

A German hosting provider or an in-house data center in Germany avoids the legal complexity that arises from third-country transfers with US cloud operation. ISO 27001 attests to 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 to a large extent, an in-house ISO 27001-certified data center in Nürnberg, a DPA on request, SSO plus automatic provisioning via the Entra ID/Azure connection, and thereby combines the API with a complete enterprise and compliance framework.

An MDM device rollout via Intune/Entra is not publicly documented and should be confirmed with the provider before signing a contract.