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Quick Start

Sign your first asset in 2 minutes and prove its authenticity.

What is CredLink?

CredLink is a C2PA-compliant content authenticity platform. We embed cryptographic signatures into your images that prove when, where, and by whom they were created and whether they've been tampered with. Unlike traditional watermarks, our signatures survive social media compression and CDN distribution.

Getting Started

  1. 1

    Create your account

    Sign up at credlink.io. Start with a 7-day free trial on the Pro plan. No credit card required to get started.

  2. 2

    Upload your asset

    From your dashboard, click "Sign New Asset" and upload an image (JPEG, PNG, WebP) or PDF. Maximum file size is 50MB.

  3. 3

    Choose signing mode

    Remote mode stores the manifest on our servers (survives CDN/social media). Embedded mode includes everything in the file (may be stripped by some platforms).

  4. 4

    Share and verify

    Get a unique verification URL for your asset. Anyone can verify authenticity by visiting the link or using our API.

Quick API Example

Prefer to integrate programmatically? Here's how to sign an image with cURL:

bash 
curl -X POST https://api.credlink.io/v1/sign \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@photo.jpg" \
  -F "mode=remote"

💡 Pro Tips

  • • Use remote mode for social media, since embedded manifests get stripped by most platforms.
  • • Set up webhooks to get notified when your assets are verified.
  • • Check the API section for SDKs in JavaScript, Python, and Go.

Signing Assets

Programmatic signing for CMS integrations and automated pipelines.

Prerequisites

  1. 1. Create an API key under Settings → API Keys
  2. 2. Export it locally:
export CREDLINK_API_KEY=sk_live_your_api_key_here

Rate limits: 5 req/s per key. Contact us for higher limits.

Signing Modes

Remote Mode (Recommended)

Manifest stored on CredLink servers, linked by content hash. Survives any image processing.

mode=remote

Embedded Mode

Manifest embedded in image metadata. May be stripped by some platforms.

mode=embedded

JavaScript SDK

javascript 
import { CredLink } from '@credlink/sdk';

const client = new CredLink('sk_live_...');

const result = await client.sign({
  file: imageBuffer,
  mode: 'remote',
  metadata: {
    author: 'Your Organization',
    title: 'Product Photo'
  }
});

console.log(result.verificationUrl);
// https://verify.credlink.io/doc_abc123

Python SDK

python 
from credlink import CredLink

client = CredLink(api_key="sk_live_...")

result = client.sign(
    file=open("image.jpg", "rb"),
    mode="remote",
    metadata={
        "author": "Your Organization",
        "title": "Product Photo"
    }
)

print(result.verification_url)

Remote Manifests

How CredLink ensures your authenticity proof survives any platform.

The Problem with Embedded Metadata

Traditional C2PA implementations embed the manifest directly into the image file. While this works for direct file transfers, most platforms strip this metadata during upload processing:

  • Twitter/X removes all EXIF and XMP metadata
  • Instagram re-encodes all images
  • CDNs optimize and strip unnecessary data
  • Messaging apps compress images

The CredLink Solution

Remote manifests store your C2PA data on our globally distributed infrastructure, linked to your image by a perceptual content hash. This means:

  • Survives any processing - compression, resizing, format conversion
  • Hosted verification - works even when platforms strip metadata
  • Instant verification - lookup by hash in under 100ms
  • 7-year retention - your proof is always available

How It Works

1

Image Upload

You upload an image with mode=remote. We compute both cryptographic and perceptual hashes.

2

Manifest Creation

We create a C2PA manifest with your metadata and sign it with our HSM-backed certificate.

3

Remote Storage

The manifest is stored on our infrastructure, indexed by both hash types for fast retrieval.

4

Verification

Anyone can verify by uploading the image (even modified). We match it to the original manifest.

Verification

Allow anyone to verify the authenticity of your signed images.

Verification Methods

Public Portal

Direct users to verify.credlink.io where they can upload any image to check authenticity.

Try the portal →

Direct Links

Each signed image gets a unique verification URL you can share or embed.

verify.credlink.io/doc_abc123

API Verification

Integrate verification into your own applications using our API.

POST /v1/verify

QR Codes

Generate QR codes that link directly to the verification page.

GET /v1/qr/{documentId}

Verification API

bash 
# Verify an image by uploading it
curl -X POST https://api.credlink.io/v1/verify \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@image.jpg"

# Response
{
  "verified": true,
  "documentId": "doc_abc123",
  "signedAt": "2025-01-24T18:49:00Z",
  "signedBy": "Your Organization",
  "manifest": {
    "title": "Product Photo",
    "claim_generator": "CredLink/1.0"
  }
}

API Reference

Complete REST API documentation for CredLink.

Base URL

https://api.credlink.io/v1

Authentication

All API requests require a Bearer token in the Authorization header:

Authorization: Bearer sk_live_your_api_key

Endpoints

POST /sign

Sign an image and create a C2PA manifest.

View parameters

file (required) - The image file to sign

mode - "remote" or "embedded" (default: "remote")

metadata - JSON object with author, title, etc.

POST /verify

Verify an image's authenticity.

View parameters

file (required) - The image file to verify

GET /documents

List all signed documents for your account.

View parameters

limit - Number of results (default: 20, max: 100)

offset - Pagination offset

GET /documents/{id}

Get details for a specific document.

Webhooks

Get notified when verification events occur.

Supported Events

  • document.signed - A new document was signed
  • document.verified - A document was verified
  • document.failed - Verification failed (invalid/modified)

Webhook Payload

json 
{
  "event": "document.verified",
  "timestamp": "2025-01-24T18:49:00Z",
  "data": {
    "documentId": "doc_abc123",
    "verifiedAt": "2025-01-24T18:49:00Z",
    "verifierIp": "203.0.113.1",
    "country": "US"
  }
}