Replacing Perspective API? It ends after 31 December 2026. Switch by changing one URLPerspective API ends 31 Dec. Switch

Profanity filtering your users can't get around

Leetspeak, look-alike letters and creative spelling are caught and named, and Scunthorpe still gets through.

Get a key Read the quickstartQuickstart

check.ts Live: edit the text

import { Unprofane } from '@unprofane/sdk';
const unprofane = new Unprofane(process.env.UNPROFANE_KEY);

const r = await unprofane.check({
  text: '',
  context: 'username',
  policy: 'teen',
  mode: 'fast',
  …
});

if (!r.allowed) refuse(r.reason);

Try

Response

Recipes and SDKs for

One call wherever people type

The code on the left is all you add. The right is what your users see, with the engine's real answers.

chat.ts

const r = await unprofane.check({
  text: message,
  context: 'chat',
  policy: 'kids',
  mode: 'fast',
});

// The room sees the censored line; nothing vanishes.
room.send(r.allowed ? message : r.censored);

Your game’s chatExample

mira_07omg that jump was insane
tomtomthis level is ****
kailol the boss has 1 hp left
mira_07******* you *****
kainice, see you next round

What they typed

this level is sh1tleetspeakblock
shut up you l0serleetspeakblock

signup.ts

const r = await unprofane.check({
  text: username,
  context: 'username',
  policy: 'teen',
  mode: 'fast',
});

if (!r.allowed) {
  return form.error('username', 'Pick another username.');
}

Your sign-up formExample

What the API said

xXsh1tl0rdXxleetspeakblock
Scunthorpe_Unitedallow
dickens_fanallow

engrave.ts

const r = await unprofane.check({
  text: engraving,
  context: 'custom_text',
  mode: 'fast',
});

if (r.action !== 'allow') {
  throw new Refusal("We can't engrave that.");
}

Your product pageExample

Walnut board, engraved

$48

Your engraving

B1TCH QUEEN

We can’t engrave that.

What the API said

B1TCH QUEENleetspeakblock
Best Dad in Scunthorpeallow
Shiitake Mushroom Cluballow

A profanity filter in 17 languages

Each has its own words, spellings and insults made of ordinary words. A line joins two languages that share a spelling: suka is a swear in Russian and means “like” in Indonesian, so the engine reads which language a sentence is in.

A form is a word in one of its spellings. A line joins two languages when a term of one is a common word of the other: 95 pairs of languages, 354 spellings. The lexicon of October 12, 2026.

Your coding agent can wire it in

Ask for “a username check at sign-up” and your agent has what it needs: an MCP server, a recipe for your stack, and the whole docs in one file.

check_text
check_batch
get_integration_snippet

llms-full.txt openapi.json MCP docs

Terminal

claude mcp add --transport http unprofane https://api.unprofane.com/mcp \
  --header "Authorization: Bearer up_test_YOUR_KEY"

.cursor/mcp.json

{
  "mcpServers": {
    "unprofane": {
      "url": "https://api.unprofane.com/mcp",
      "headers": { "Authorization": "Bearer up_test_YOUR_KEY" }
    }
  }
}

.vscode/mcp.json

{
  "inputs": [{
    "type": "promptString", "id": "unprofane-key",
    "description": "Unprofane key", "password": true
  }],
  "servers": {
    "unprofane": {
      "type": "http",
      "url": "https://api.unprofane.com/mcp",
      "headers": { "Authorization": "Bearer ${input:unprofane-key}" }
    }
  }
}

Then askCheck usernames at sign-up with Unprofane, and show the reason when one is refused.

Will it block my real users?

Not for living in a town, quoting a word in a lesson or a villain's line in a story. These are the API's answers, in the languages they were written in.

Gets through

Moving to Scunthorpe next month
English, generalby the modelallow
Whole words only, and the innocent list.
Le patient présente une douleur au sein gauche et au pénis.
French, generalby the modelallow
Body words in a medical sentence.
La palabra «puta» tiene muchos usos en el español de América.
Spanish, a lessonby the modelallow
A lesson about a word.
«Я тебя убью», прошептал злодей и исчез в тумане.
Russian, fictionby the modelallow
Dialogue in fiction is the story’s.
איזה אידיוט אני, שכחתי שוב את המפתחות
Hebrew, chatby the modelallow
The writer is the idiot; aimed at someone, the same word blocks.
gg ez, uninstall
English, game chatby the modelallow
A taunt about play; in chat the same line is an insult.
He told me I was worthless and I cried all night.
English, chatby the modelallow
The writer reports what was said to them.

Gets caught

xXsh1tl0rdXx
English, a usernameby the rulesblock
Split into words and decoded.
you're such a b1tch
English, chatby the rulesblock
Read as the word, and the disguise named.
ƒυ¢к off
English, chatby the rulesreview
A hooked f, a Greek u, a cent sign and a Cyrillic k.
v a i s e f o d e r
Portuguese, chatby the rulesblock
Portuguese, joined back into its words.
eres un pedazo de 💩
Spanish, chatby the rulesblock
The picture reads as its Spanish word inside the phrase; alone it is a picture.
what an Arschloch move, seriously
German, chatby the rulesblock
A German insult in an English sentence.
Nice family you have. Shame if something happened to them.
English, chatby the modelblock
No listed word; the model reads the threat.

Standard policy, the API's default mode. Recorded on engine 2026-09-29, October 8, 2026. All 24 examples in 9 languages.

Where a word list goes wrong

The same texts through a list of our own English words matched as typed, and through the rules alone, in fast mode. The model is not asked.

Moving to Scunthorpe next month
The list finds a slur inside a town.
Blocks it
allow
f.u.c.k off, nobody wants you here
Four dots and the list sees no word.
Misses it
block
ƒυ¢к off
A hooked f, a Greek u, a cent sign and a Cyrillic k.
Misses it
review
I know where you live
A threat in ordinary words.
Misses it
block

Out of 4

1 innocent blocked3 missed

1 innocent let through3 caught

89.0%
of toxic text caught, with 7.0% of clean text flagged
Head to head, on judged text
On the same texts, labelled blind, and allowed the same share of false alarms, Google's Perspective API catches 58.4% and OpenAI moderation 40.8%. Where our own false alarms fall is published beside it. See the head to head.
The private test set, 9,029 texts labelled blind, read once on 2026-09-28, engine 2026-09-29
13
disguise techniques, each one caught and named
Hard to fool
From leetspeak to zero-width characters to a word read backwards, each is undone before the words are read and named in the response. The weakest is caught 89% of the time; the rest better.
- homoglyph
- zero_width
- separator
- leetspeak
- repeated_chars
- diacritics
- mixed_script
- fullwidth
- combining_marks
- phonetic
- reversed
- concatenation
- case_mixing
Per-technique recall, 2026-10-12-11-25-45-dev.json
0.0%
false positives on innocent text
Does not block Scunthorpe
Measured on 1,447 innocent words and phrases that contain a profane string: places, surnames, animals, tools, anatomy in a medical sentence. Each one is a test.
The Scunthorpe Test, 2026-10-12
5ms
at p99, inside the Worker
Fast where it must be
For a check the rules answer, which is most of them. The model is asked only about text the rules cannot settle, and every response says which route answered.
Our own measurement in workerd, 300 requests, 2026-09-28

79days left

Google's Perspective API ends after 31 December 2026

Same path, same JSON, same errors, the key as ?key=. Change the base URL and keep the client. Guides for Coral, Discourse, Python and Node, and a replay tool that maps your thresholds.

Migration hub

Private by architecture

No request text is stored: not in a database, a cache, a log or a trace.
Text the rules answer never leaves Cloudflare.
A project can be set to Edge-only so no text ever reaches a model.

Each promise is a test in the source, and the privacy page says them in plain words.

Pricing

A check is one text. Each step up costs less per check, and checks past the allowance go on the same invoice.

50% offThe first 3 months of any plan, for a first subscription started by January 31, 2027. Applied at checkout.

Research plans are free by application. Enterprise adds a zero-retention model tier, a custom lexicon and invoice billing. All plans.