Best NSFW Detection APIs Compared: 2026 Guide

Choosing the right NSFW detection API can save your platform from legal liability, app store removal, and advertiser pullbacks. Here's how the top image moderation APIs compare.

Quick Comparison

API	Categories	Scoring	Setup
AI Engine NSFW Detect	10 (hierarchical)	Confidence 0-100, with sub-labels	RapidAPI key
Google Vision	5 (SafeSearch)	Likelihood levels	GCP + billing
Clarifai	5 concepts	Probabilities	API key

AI Engine NSFW Detect — Python Example

import requests

url = "https://nsfw-detect3.p.rapidapi.com/nsfw-detect"
headers = {
    "x-rapidapi-host": "nsfw-detect3.p.rapidapi.com",
    "x-rapidapi-key": "YOUR_API_KEY",
    "Content-Type": "application/x-www-form-urlencoded",
}

response = requests.post(url, headers=headers, data={"url": "https://example.com/photo.jpg"})
result = response.json()

for label in result["body"]["ModerationLabels"]:
    print(f"{label['Name']}: {label['Confidence']:.1f}%")

10 categories with hierarchical sub-labels: Explicit, Non-Explicit Nudity of Intimate parts and Kissing, Swimwear or Underwear, Violence, Visually Disturbing, Rude Gestures, Drugs & Tobacco, Alcohol, Gambling, Hate Symbols.

Three-Tier Moderation Pipeline

BLOCK_CATEGORIES = {"Explicit", "Violence", "Hate Symbols"}
WARN_CATEGORIES = {
    "Non-Explicit Nudity of Intimate parts and Kissing",
    "Swimwear or Underwear",
    "Drugs & Tobacco",
    "Alcohol",
}

def moderate(image_url: str) -> str:
    response = requests.post(url, headers=headers, data={"url": image_url})
    labels = response.json()["body"]["ModerationLabels"]
    # Top-level labels have an empty ParentName
    top_level = [label for label in labels if label["ParentName"] == ""]

    for label in top_level:
        if label["Name"] in BLOCK_CATEGORIES and label["Confidence"] > 80:
            return "block"
    for label in top_level:
        if label["Name"] in WARN_CATEGORIES and label["Confidence"] > 70:
            return "warn"
    return "allow"

When to Choose Each

• Quick start, no cloud setup → AI Engine. One API key, running in 5 minutes
• Basic safe/unsafe filtering → Google Vision SafeSearch
• Custom moderation rules → Clarifai (train your own models)

👉 Read the full comparison with feature breakdowns and decision framework