Free DevOps Tools — Cron, CIDR, Config, Network

DevOps work is a steady stream of small checks: does this cron expression run when I think it does, how many addresses are in this network range, is this configuration file valid, what does this header mean. The DevOps tools on this page answer those questions in a browser tab, without installing anything or sending your configuration to a third party.

The tools explain their results in plain words next to the technical output. A cron expression is described in English with the next run times, a CIDR block is expanded into its first and last address and size, and configuration formats are validated with line-numbered errors.

Everything runs on your device. The few tools that need the network, such as ones that look something up on the internet, say so clearly on their page, and nothing is sent unless you press the main button. Star the checks you repeat every week and they will be waiting at the top of All tools.

All DevOps tools

31 tools

Cron ParserUnderstand a cron schedule in plain English

Subnet CIDR CalculatorWork out IP ranges for networks

User-Agent ParserSee which browser and device a visitor uses

Docker Compose BuilderBuild a Docker setup by picking services

Dockerfile LinterFind problems in a Dockerfile

Kubernetes YAML ValidatorCheck Kubernetes files before deploying

.env Parser & ValidatorCheck .env settings files

.gitignore GeneratorCreate a .gitignore for your project

Nginx Config GeneratorCreate a web server config

.htaccess GeneratorCreate redirects and HTTPS rules

chmod CalculatorWork out file permission numbers

Crontab GeneratorBuild a schedule by picking times

SSH Key GeneratorCreate SSH keys for servers and Git

Semver CalculatorCheck version ranges like ^1.2.0

HTTP Status CodesWhat every website error code means

MIME Type LookupFind the right file type label

Port Number ReferenceCommon network ports and what uses them

GitHub Actions ValidatorCheck GitHub workflow files

Docker Run to ComposeTurn docker run commands into a file

IP Address ConverterConvert IP addresses between formats

MAC Address FormatterFormat device hardware addresses

DNS LookupSee where a website points (DNS records)

Email Address ValidatorCheck if an email address looks right

Phone Number FormatterCheck and format phone numbers

HTTP Header ParserCheck a site's security headers

Cookie ParserRead cookies and spot unsafe settings

Luhn / Test Card ValidatorCheck card numbers and get test cards

TOTP / 2FA Code GeneratorTest 2-step login codes

UTM Link BuilderCreate trackable links for campaigns

IPv6 ULA GeneratorCreate private IPv6 address ranges

MAC Address LookupFind who made a network device

Frequently asked questions

Do these tools need an internet connection?

Most work offline once opened. A tool that has to look something up online says so on its page.

Is my configuration uploaded?

No. Validation and formatting run in your browser, so configuration files and hostnames stay on your device.

Which cron syntax is supported?

Standard five-field cron and the six-field form with seconds, including lists, ranges and steps. The next run times are computed by the same library used by many schedulers.

Will more DevOps tools be added?

Yes. This page lists tools as they are released, grouped with the cron and network tools you already use.

More tool groups

Security tools · Converters · All tools