SafePrompt · Prompt injection detection API
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SafePrompt
Prompt injection detection API for LLM apps and agents.

The same protection on every plan

Every plan runs the same detection engine, so the free key blocks the same attacks the paid ones do. Free covers a side project. Paid adds production volume, your own allow and block phrases, IP threat intelligence, higher rate limits, and one toggle that keeps your traffic out of the shared network. That sharing starts on, and you switch it off in dashboard settings.

Cancel anytime
No setup fees
No per-request fees

Pricing last reviewed: 12 September 2026

How much does prompt injection detection cost?

Free

$0/month

Covers a side project at no cost

No card. Your key on the next screen.

10,000 validations a month
10 requests/second
Instant signup, your key on the next screen
The same detection engine as every paid plan
Pattern matching plus AI semantic analysis
Reads a conversation as one session with a session token
Blocked attacks join the shared network defence that every plan runs on (opt-out on paid plans)
Export your data, and erase your last 24 hours, from the dashboard
Default phrase lists included
See your top 3 attacks in the dashboard
RECOMMENDED

Starter

$29/month

Covers a live app with real users

Instant access • Cancel anytime

500,000 validations a month
50 requests/second

Everything in Free, plus:

IP threat intelligence, so repeat attackers are known before they reach you
Keep your traffic out of the shared network with one toggle
25 phrases you always allow, so your own jargon never trips the check
25 phrases you always block, in your own words
Edit the default phrase lists to match your app
Advanced threat detection
Usage analytics dashboard (24h / 7d / 30d timeline)
Detection-method breakdown
Top-10 attack categories
SCALE

Business

$99/month

Covers a team running at volume

Instant access • Cancel anytime

1,000,000 validations a month

Everything in Starter, plus:

Email support, 2 business day target
100 phrases you always allow
100 phrases you always block
100 requests/second
We run the infrastructure, you run one API call
Network-wide attack campaign feed
Auto-discovered pattern proposals
Full attack taxonomy (14 categories)

No overage billing, ever

A paid plan renews at the same price each month until you cancel, and there is no overage billing. Requests past your plan's monthly limit come back as an HTTP 429 carrying the date your quota resets, and your traffic flows again on that date or the moment you upgrade.

Frequently Asked Questions

How much does prompt injection detection cost?

Every plan runs the same detection engine, starting at $0/month. The free tier gives you 10,000 validations a month. Starter is $29/month for 500,000 validations. Business is $99/month for 1,000,000 validations. No per-request fees, no hidden costs, and no credit card for the free tier.

Is there a free prompt injection API?

Yes. SafePrompt gives you 10,000 API validations a month at no cost, on the same detection engine paid plans run: pattern detection, external reference detection and AI validation. No credit card. Sign up with your email and your key is on the next screen. Blocked attacks from free-tier traffic join the shared network defence. Paid plans can turn that contribution off in Privacy Settings.

What's included in SafePrompt's free tier?

The free tier includes 10,000 validations a month, the full detection engine (the same one paid plans run), pattern and AI validation, session tracking, and the shared network defence. Export your data yourself from the dashboard, and erase the identifiable data from your last 24 hours there too. Paid plans add production volume, IP threat correlation and an intelligence opt-out.

Is the free plan really free?

Yes. Confirm your email and your key appears on the next screen: 10,000 validations a month, no card and no time limit. The one condition is that attacks blocked on the free plan join the shared network defence; paid plans can switch that off. Until you do, a paid plan stores every request you send, safe and blocked, while the free plan stores only the prompts we block.

Can I change plans later?

Yes. Upgrade any time, downgrade at the end of any billing cycle. No contracts and no penalties.

Can I cancel anytime?

Yes. Cancel any time from your dashboard. No cancellation fees and no questions asked.

Do I need a credit card for free?

Your email is all we need. You get a working key on the next screen and your first check runs in minutes.

What's included in all plans?

Every plan runs the same engine: pattern detection, AI validation, session tracking and the shared network defence.

Can I upgrade from Free to Starter?

Yes. Upgrade from your dashboard settings any time. Your new quota is live as soon as payment confirms.

Do I get locked into a specific LLM provider?

SafePrompt checks the text before it reaches your model, so it works with OpenAI, Anthropic, Google, Mistral and anything else you run. Switch providers any time with no change on your side, and export your data from the dashboard on any plan.

Why pay when open-source tools like LLM Guard are free?

SafePrompt is one API call with nothing to run: no model to host, no GPU to size, no rules to maintain, and a free tier so you can start today. Run LLM Guard self-hosted if your data can never leave your own machines.