Content Moderation API: The Complete Guide (2026)
Everything you need to choose and use a content moderation API in 2026: what it is, how it works, the categories it covers, how to compare providers, what it costs, and how to add it to your app.
In this guide
What a content moderation API is
A content moderation API is a service you send user-generated content to and get back a real-time decision: whether it violates your policy, which category it hits, and how confident the system is. It lets you add moderation with a single HTTP call instead of building and hosting your own models. For the plain-English definition, see what is content moderation.
How it works
You POST a message or image to the API. It normalizes the text (to defeat evasion like leetspeak and unicode look-alikes), runs it through classifiers or a language model, and scores it across categories. If a score crosses your threshold, you get a flag and a reason, and your app decides what to do: block, hide, warn, or queue for review. The best systems let you define the policy yourself rather than forcing a fixed taxonomy.
What it detects
Common categories include hate and discrimination, harassment, sexual content, violence, self-harm, dangerous content, PII, profanity, and spam. Platforms with younger users also need grooming detection. A strong API lets you tune each category's threshold and add a custom rule for anything the standard categories miss.
How to choose one
- Content type: text, image, voice, or video, since not every API covers all.
- Fixed categories vs custom policy: can you express your exact rules, or only pick from theirs?
- Compliance: PII redaction, COPPA, and EU/UK data residency for GDPR.
- Cost model: per-1,000 pricing, free tier, minimums, and lock-in.
- Latency and evasion resistance for real-time chat.
The main providers compared
We have written head-to-head comparisons for each major provider. Start with the roundup, then the specific matchup for whichever you are evaluating:
Pricing
Costs range from free (OpenAI Moderation, Google Perspective, for text) to premium multimodal suites at $1.50-$3 per 1,000. See the full content moderation API pricing comparison and the guide to free content moderation APIs. Paxmod sits at the affordable end: $0.25 per 1,000 messages with a free tier and no minimums.
By use case
- Gaming chat moderation — real-time, evasion-resistant, COPPA-ready.
- Forums and communities — moderate posts and comments at scale.
- Marketing campaigns — auto-moderate social and ad comments.
- Profanity filtering — beyond static word lists.
- Unity and Roblox game integrations.
How to get started
Try any message in the free moderation tester (no signup), then read the API docs to integrate. Paxmod is one REST call, text and images, custom policies in plain English, free to start.
Frequently Asked Questions
What is a content moderation API?
A service you send user content to and get back a real-time policy decision, so you can add moderation with an HTTP call instead of building your own models.
How do I choose one?
Match it to your content type, whether you need custom policies, your budget, and compliance needs like PII and data residency.
How much does it cost?
Free for text on OpenAI/Perspective, up to $1.50-$3 per 1,000 for premium multimodal. Paxmod is $0.25 per 1,000 with a free tier.
Add content moderation to your app
One API for text and images, custom policies in plain English, from $0.25 per 1,000 messages. Free to start.