Do I need to sign up to use the NSFW Checker API?

No. The free tier works without any account, API key, or signup. You get 100 requests per day, rate limited by your IP address. Just send a POST request with an image to https://api.nsfwcheckers.workers.dev and get a JSON result with a safe/unsafe classification and confidence score.

What image formats does the NSFW detection API support?

The API supports JPEG, PNG, WebP, and GIF images up to 10MB in size. Send the image as multipart/form-data with the field name 'image', or as a raw binary request body. Both methods produce identical results. The API automatically detects the image format.

Are uploaded images stored or logged?

No. All images are processed entirely in memory on edge workers and immediately discarded after classification. Nothing is written to disk, stored in a database, or logged. We have no ability to retrieve, review, or access any image after processing. See our privacy policy at nsfwcheckers.com/privacy for full details.

How accurate is the NSFW detection?

The API uses Microsoft's ResNet-50 deep learning model, a 50-layer convolutional neural network trained on millions of labeled images from ImageNet. It reliably detects nudity, swimwear, lingerie, and explicit content. The confidence score (0 to 1) lets you set your own threshold — lower for stricter moderation, higher for more permissive. Like all AI models, edge cases with suggestive but clothed content may vary.

What happens when I reach the daily API limit?

You receive a 429 (Too Many Requests) HTTP status code with a JSON response containing your current usage count, remaining quota, and daily limit. The limit resets at midnight UTC every day. You can monitor your usage in real-time using the 'used' and 'remaining' fields in every API response.

Can I use the NSFW Checker API in commercial projects?

Yes. All plans including the free tier are available for commercial use in production applications. No attribution is required. You can integrate it into any app, website, platform, or service. The API is suitable for social media platforms, dating apps, image hosting services, forums, and AI image generators.

What AI model powers the NSFW detection?

NSFW Checker uses Microsoft's ResNet-50 (Residual Network with 50 layers), a deep convolutional neural network originally trained on the ImageNet dataset. It runs on a global edge network infrastructure across 300+ global edge locations, providing sub-500ms inference times regardless of user location.

When will paid plans be available?

Pro (5,000 requests/day at $9/month) and Business (50,000 requests/day at $29/month) plans are coming soon. Both will include dedicated API keys, priority processing, and a usage dashboard. The free tier with 100 requests per day is fully available now with no restrictions.

NSFW Detection for User-Generated Content: A Complete Guide

How to implement NSFW image detection for forums, social apps, dating platforms, and other UGC-heavy applications.

NSFW Checker Team

April 7, 2026 · 5 min read

The UGC moderation challenge

User-generated content (UGC) platforms face a unique challenge: users upload millions of images daily, and even a small percentage of explicit content can create serious problems — app store removal, legal liability, advertiser pullback, and user trust erosion.

Manual moderation cannot keep up. Automated NSFW detection is the first line of defense.

Types of platforms that need NSFW detection

Social media and forums

Community platforms like Reddit, Discord servers, and niche forums need to moderate images in posts, comments, and direct messages.

Dating apps

Profile photos and chat images must be screened. A single explicit image in a match queue can lead to user reports and app store violations.

Image hosting services

Services like Imgur or custom image hosts need to prevent explicit content from being shared via public links.

AI image generators

With the rise of AI-generated images, safety filters are essential to prevent models from producing explicit content.

E-commerce

Product listing images need moderation to prevent inappropriate content from appearing in search results and catalogs.

Implementation strategies

Pre-upload moderation

Check every image before it is stored or displayed:

// In your upload handler
const result = await checkNSFW(imageFile);
if (result.nsfw) {
  return { error: "This image violates our content policy" };
}
// Proceed with upload

**Pros**: No explicit content ever appears on your platform.

**Cons**: Adds latency to the upload process.

Post-upload moderation

Display the image immediately but check it asynchronously:

// Save and display immediately
await saveImage(imageFile);

// Check in background
checkNSFW(imageFile).then(result => {
  if (result.nsfw) {
    removeImage(imageId);
    notifyUser("Your image was removed for violating content policy");
  }
});

**Pros**: Faster user experience.

**Cons**: Brief window where explicit content is visible.

Hybrid approach

Show a blurred placeholder until moderation completes, then reveal the original if safe. This balances speed and safety.

Setting the right threshold

The NSFW Checker API returns a score from 0 to 1. The default threshold is 0.5, but you should adjust based on your platform:

Children's app: 0.3 (stricter, more false positives but safer)

General social platform: 0.5 (balanced)

Adult-friendly platform: 0.7 (more permissive)

Handling edge cases

No AI model is perfect. Plan for:

False positives: Medical images, art, swimwear catalogs may be flagged. Allow users to appeal.

False negatives: Some borderline content may pass. Combine AI detection with user reporting.

Text-based NSFW: The image API does not detect NSFW text overlaid on images. Use a separate text moderation tool.

Getting started

Integrate NSFW detection into your UGC platform with a single API call:

curl -X POST https://api.nsfwcheckers.workers.dev -F "image=@upload.jpg"

100 free requests per day, no signup required. Scale to thousands with paid plans when you need them.