Non-Working Days API

⭐ Beginner's Pick Calendar / No Auth Required Beginner HTTPS CORS
Free to Use Varies (check documentation)

Overview

IsDayOff.ru is a minimalist REST API that returns whether a given date is a working day, non-working day, or short (pre-holiday) day for Russia and several CIS countries, as well as the United States. The response is a single character (0, 1, or 4), making it trivially easy to parse in any language. No authentication is required.

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Beginner Tip

This is one of the most beginner-friendly APIs available: no key, no JSON parsing — just a GET request that returns a single digit. Try it in your browser by visiting https://isdayoff.ru/20250101 to see the result immediately.

Available Data

Non-Working Days data via REST API
JSON-formatted response data
Freely accessible without authentication

Example Response

JSON Response
{
  "input": "[email protected]",
  "is_valid": true,
  "format_valid": true,
  "details": "Input passes all validation checks"
}

Field Reference

(response body) Single character: 0 means working day, 1 means non-working day, 4 means short pre-holiday day, 100 means an error occurred

Implementation Example

const url = "https://isdayoff.ru/";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

Response is '100' (error code) The date format is wrong or the date is outside the supported range
Use YYYYMMDD format with no dashes, e.g. 20250101 instead of 2025-01-01.
Unexpected result for non-Russian dates The default country is Russia; other countries must be specified explicitly
Add the cc query parameter: ?cc=us for United States, ?cc=ua for Ukraine, etc.
Empty or unexpected response body The date string contains URL-unsafe characters or extra whitespace
Ensure the date string is plain digits in YYYYMMDD format with no spaces or punctuation.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 15/20
🔒 Security 15/15
🛠 Developer XP 20/20
✓ Reliability 7/15
Response Time 308ms

Fully tested on Apr 5, 2026

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS YES
Category Calendar
Difficulty Beginner
Verified: 2026-04-07

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