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Overview

The Messaging API enables secure, encrypted communication between your application and UIP users. Send text messages, documents for signing, legal contracts, and other important communications with configurable notification priorities.

Text Messages

Secure notifications, alerts, and communications without attachments

Document Messages

Contracts, legal documents, and files requiring signature with full audit trail

Encrypted Delivery

End-to-end encryption ensures only the recipient can read your messages

Signature Collection

Request signatures on messages and documents with cryptographic proof

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Message Types

Perfect for:
  • Account notifications and alerts
  • Password reset confirmations
  • Transaction confirmations
  • System status updates
  • General communications
Pricing: $0.03 per message

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Notification Severity Levels

Control how urgently users are notified about your messages with four severity levels:

Low

No push notification - Background delivery only.User sees message when they open the UIP app. Perfect for non-urgent notifications, marketing messages, or optional updates.Use for: Non-urgent updates, promotional content, informational messages
Standard push notification with default sound and vibration.User receives immediate notification but not intrusive. Perfect for most use cases.Use for: Account notifications, transaction confirmations, general alerts
Priority notification with enhanced sound and persistent alert until acknowledged.User receives prominent notification that stays visible. Perfect for important actions requiring attention.Use for: Contract signing requests, security alerts, payment confirmations
Emergency-level notification with maximum alert intensity.
Restricted Access: Extreme severity is only available to verified government and emergency service accounts.
Reserved for critical situations requiring immediate action.Use for: Emergency alerts, public safety notifications, critical government communications

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Use Cases

Scenario: Send employment contract for signatureSend a PDF contract with signature request. When the recipient signs, you receive a webhook with the signature proof and audit ID.Benefits:
  • Legally binding signatures
  • Permanent audit trail
  • No physical paperwork
  • Instant completion

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Invalidating Messages

If you send a message that requires a signature, you can invalidate it before the recipient signs using the Invalidate Message API.
When to Invalidate: Cancel pending signature requests if terms change, deadlines pass, or the request is no longer needed.

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How It Works

1

Send Message

Send a message with signature request to a recipient
2

Recipient Hasn't Signed

Before the recipient signs, you decide to cancel the request
3

Call Invalidate API

Use the Invalidate Message API to cancel
4

Request Cancelled

The recipient can no longer sign the message. They’ll see it was cancelled.
Use cases for invalidation:
  • Contract terms changed before signing
  • Recipient should sign updated version
  • Request sent to wrong person
  • Deadline passed without signature
  • Agreement cancelled by another party
Once a recipient signs a message, it cannot be invalidated. The signature is permanent and stored in the audit trail.

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Supported File Types

PDF Documents Only

Only PDF documents (.pdf) are supported for attachments.You can attach multiple PDFs per message, with a cumulative maximum size of 20MB total.

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Pricing

Text Messages

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$0.03

per messageNo attachment, text-only communication

Messages with Attachment

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$0.10

per messageIncludes documents up to 20MB with signature support
Billing: Only charged when messages are successfully delivered. Failed deliveries are not billed.

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Best Practices

Choose Severity Wisely

Don’t overuse high/extreme severity. Users will ignore notifications if everything is urgent.

Clear Subject Lines

Make subjects descriptive and actionable. “Action Required: Employment Contract” is better than “New Message”

Save Audit IDs

Always save audit IDs from signature webhooks for permanent proof and compliance.

Test Webhooks

Use the Test Webhook endpoint before going live.

Handle Declines Gracefully

Signature declines are normal. Provide clear follow-up actions or retry options.

Optimize PDFs

Compress PDFs before sending to stay under the 20MB cumulative limit.

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Next Steps

Get API Keys

Start sending encrypted messages

API Reference

Complete API reference with request/response schemas

Invalidate Message

Learn how to cancel pending signature requests