REST / JSON

API docs

JSON API: prepaid key balance, per-request billing, the same engine as the web UI.

Quick start in three calls

Create a key — you get a csscl_… with a trial balancecurl -X POST https://css-cleaner.ru/api/v1/key -H "Content-Type: application/json" -d '{"name":"my-app"}'
Top up the balance: card, SBP, crypto or the sandboxcurl -X POST https://css-cleaner.ru/api/v1/topup -d 'key=csscl_XXXX&amount=500&provider=yookassa'
Send CSS — get clean CSS back plus a reportcurl -X POST https://css-cleaner.ru/api/v1/dedup -H "X-API-Key: csscl_XXXX" -d '{"css":".a{color:red}.a{color:red}"}'

There is no account: the key is the wallet. Lose the key, lose the balance.

Authentication

Pass the key in any of these three ways.

X-API-Key: csscl_XXXXXXXXXXXXXXXX
Authorization: Bearer csscl_XXXXXXXXXXXXXXXX
POST /api/v1/dedup?key=csscl_XXXXXXXXXXXXXXXX

Without a key you get 20 free requests per day per IP — fine for tests, get a key for production.

Endpoints

Method and path	What it does	Price
`POST /api/v1/dedup`	Removes duplicates and empty rules, safely merges repeated selectors.	$0.0011
`POST /api/v1/filter`	Keeps only the rules that actually match the HTML you send.	$0.0022
`POST /api/v1/block`	Extracts one block's styles, including inherited html/body rules and every var() it needs.	$0.0033
`POST /api/v1/key`	Create a key with a trial balance	free
`GET /api/v1/key`	Balance, spend, request count, current prices	free
`POST /api/v1/topup`	Top-up invoice — returns the checkout URL	free
`POST /api/dedup · /api/filter · /api/block`	The same three jobs, key-less and unbilled	free

Request parameters

`POST /api/v1/dedup`

Field	Type	Required	Meaning
`css`	string	yes	the whole stylesheet, exactly as in the file
`strip_comments`	bool	no	strip comments (off by default)
`merge_overrides`	bool	no	merge identical selectors into one rule — only when properties do not conflict

`POST /api/v1/filter`

Field	Type	Required	Meaning
`css`	string	yes	the whole stylesheet, exactly as in the file
`html`	string	yes	the page HTML the CSS is cleaned against
`drop_keyframes`	bool	no	drop @keyframes nothing animates
`drop_fonts`	bool	no	drop unused @font-face

`POST /api/v1/block`

Field	Type	Required	Meaning
`css`	string	yes	the whole stylesheet, exactly as in the file
`html`	string	yes	the page HTML the CSS is cleaned against
`target`	string	yes	block selector: .card, #hero, main .btn
`prune`	bool	no	drop declarations the cascade overrides later anyway
`drop_keyframes`	bool	no	drop @keyframes nothing animates
`drop_fonts`	bool	no	drop unused @font-face

`POST /api/v1/topup`

Field	Type	Required	Meaning
`key`	string	yes	the API key to top up
`amount`	number	yes	amount in rubles: 100 to 100000
`provider`	string	no	yookassa · robokassa · cryptocloud · demo (empty = first available)

Response

A successful call returns JSON with the result and a report. Money is in kopecks.

{
  "ok": true,
  "endpoint": "block",
  "charged": 30,
  "price": 30,
  "balance": 970,
  "output": ":root { --brand: #3b82f6; } body { color: #222; } .card { padding: 24px; }",
  "report": {
    "rules_total": 14, "rules_kept": 9, "rules_dropped": 5,
    "elements_matched": 1, "inherited_kept": ["html", "body", ".content"],
    "var_names": ["--brand", "--gap", "--text"],
    "saved_bytes": 412, "reduction": 38.4
  }
}

Field	Meaning
`output`	the cleaned CSS as a single string
`charged` · `price` · `balance`	what was charged, the price, the remaining balance
`report.saved_bytes` · `report.reduction`	bytes saved and the percentage
`report.rules_before` · `rules_after` · `duplicates` · `empty` · `merged_groups`	dedup stats: rules before/after, duplicates, empty rules, merges
`report.rules_kept` · `rules_dropped` · `elements_matched` · `keyframes_dropped` · `fonts_dropped`	filter stats: kept, dropped, how many elements matched
`report.inherited_kept` · `var_names` · `decls_pruned` · `target`	for a block: inherited selectors, variable names, pruned declarations

Errors

Every error is JSON of the shape {"error": "…"}.

HTTP	Meaning
`400`	missing css/html or malformed JSON
`401`	key unknown or not supplied
`402`	insufficient balance
`403`	key disabled
`404`	unknown endpoint, e.g. /api/v1/pretty
`413`	input larger than 2 MB
`429`	daily free limit reached

Limits

up to 2 MB of CSS per request — more than any real site needs
up to 60 seconds per request
20 free requests per day per IP without a key
you pay per request, not per byte: 2 MB and 2 KB cost the same

Code samples

JavaScript (fetch)

const r = await fetch("https://css-cleaner.ru/api/v1/filter", {
  method: "POST",
  headers: { "Content-Type": "application/json", "X-API-Key": "csscl_XXXX" },
  body: JSON.stringify({ html: document.documentElement.outerHTML, css, drop_keyframes: true }),
});
const { output, report } = await r.json();
console.log(`−${report.saved_bytes} б, −${report.rules_dropped} правил`);

Python (requests)

import requests

r = requests.post("https://css-cleaner.ru/api/v1/block",
                  headers={"X-API-Key": "csscl_XXXX"},
                  json={"html": html, "css": css, "target": ".card", "prune": True},
                  timeout=60)
r.raise_for_status()
print(r.json()["output"], r.json()["balance"])

Create key Pricing