OpenLetter

Paid

★ 1 • Updated Aug 2, 2026, 09:11 AM

OpenLetter is an API service that allows developers to programmatically create and send beautiful digital invitations for special events.

Use Cases ▼

Automated wedding invitation sending via an app

Corporate event invitation generation from CRM systems

Birthday party invitation creation for a social platform

Building a digital invitation marketplace

Sending personalized save-the-date cards

Integrating invitation templates into an email marketing tool

What Problem It Solves ▼

OpenLetter automates the creation and delivery of personalized event invitations, eliminating the need for manual design and sending processes, and enabling developers to integrate invitation functionality into their applications rapidly.

Key Features ▼

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Saves development time on invitation design

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Scalable API for high-volume sending

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Beautiful, customizable templates

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Easy integration with existing apps

Overview

OpenLetter is an API service that allows developers to programmatically create and send beautiful digital invitations for special events. It provides a set of endpoints to generate customized invitation cards with various templates, personalization options, and delivery mechanisms. The service abstracts away design complexities, enabling automated invitation workflows.

Full Description ▼

Designed for scalability, OpenLetter can handle high volumes of invitations, making it suitable for applications that need to send event notifications en masse. Integration requires API key authentication, and the service offers detailed documentation for implementation.

The API supports different invitation formats and can connect to email or SMS gateways for delivery. It aims to save time for developers building event management, CRM, or communication platforms by providing ready-to-use invitation generation capabilities.

As a paid service, OpenLetter offers tiered pricing based on usage, with higher tiers providing additional features like advanced analytics, priority support, and white-label options. The service ensures high deliverability and includes tracking features to monitor invitation opens and responses.