DevToolkit

Browser-only tools for practical production work

Browser-based developer toolbox

DevToolkit

Browser-based tools for developers, DevOps, self-hosters, and webmasters.

Generate Docker, HTTP, security, SEO, JSON, encoding, and network outputs with local-only processing and practical warnings for real-world configs.

Browse all tools View workflows

Searchable browser-only utilities

Search tools like Docker, CORS, JSON, SEO, headers...

Search tools

No login

No upload

Browser-only

Copy-ready

Practical warnings

Workflow map

One local toolbox for setup, checks, and handoff snippets

No upload

Self-host

Compose env, volumes, proxy snippets

Web debug

Headers, CORS, redirects, status codes

SEO basics

Meta tags, robots.txt, sitemaps, slugs

API data

JSON, JWT, Base64, URL encoding

Browser-only

Paste, generate, copy, and clear. DevToolkit keeps these workflows client-side and focused on practical output.

Featured tools

Featured Self-hosting Tools

Docker, reverse proxy, and HTTP security helpers for self-hosted deployments, all generating output in the browser.

DevOps / Self-host

Docker Compose Env File Generator

Generate Docker Compose .env files, env_file snippets, and environment blocks in your browser with warnings for duplicate, empty, or sensitive variables.

Local-onlyNo uploaddockercomposeenv

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DevOps / Self-host

Docker Volume Mapping Helper

Generate Docker volume mappings for docker run and docker-compose in your browser, with bind mount, named volume, read-only, SELinux, and path safety warnings.

Local-onlyNo uploaddockervolumevolumes

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DevOps / Self-host

Docker Run to Compose Converter

Convert docker run commands into best-effort docker-compose.yml files in your browser before you extend a self-hosted or VPS stack.

Local-onlyNo uploaddockerruncompose

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DevOps / Self-host

Docker Compose to Docker Run Converter

Convert docker-compose.yml services into docker run commands in your browser when you need a runnable handoff, a VPS recovery path, or a single-service debug command.

Local-onlyNo uploaddockercomposedocker-compose

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DevOps / Self-host

Docker Compose Preview

Review docker-compose.yml files in your browser and inspect services, ports, volumes, env values, and networks before you wire them into a proxy or VPS.

Local-onlyNo uploaddockercomposedocker-compose

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DevOps / Self-host

Nginx Reverse Proxy Generator

Generate Nginx reverse proxy config snippets for Docker apps, self-hosted services, WebSocket apps, SSL setups, and header workflows in your browser.

Local-onlyNo uploadnginxreverse proxyproxy

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DevOps / Self-host

Caddyfile Generator

Generate Caddyfile reverse proxy snippets for Docker services, self-hosted apps, HTTPS sites, compression, security headers, and access logs in your browser.

Local-onlyNo uploadcaddycaddyfilereverse proxy

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Web / SEO

HTTP Security Headers Checker

Check pasted HTTP response headers for common security headers, risky values, missing protections, and browser-side recommendations.

Local-onlyNo uploadhttpheaderssecurity

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Common Workflows

Jump into a practical tool chain

Each workflow groups copy-ready tools that usually belong together during deployment, debugging, SEO preparation, or API work.

Workflow

Deploy a self-hosted app

Prepare Docker environment files, volume mappings, reverse proxy snippets, and header checks before you ship a service.

Docker Compose Env File Generator Docker Volume Mapping Helper Nginx Reverse Proxy Generator Caddyfile Generator HTTP Security Headers Checker

Workflow

Debug website headers and CORS

Parse response headers, review security protections, generate CORS snippets, and prepare redirect rules for web apps.

HTTP Headers Parser HTTP Security Headers Checker CORS Header Generator / Checker Redirect Rules Generator

Workflow

Prepare SEO basics

Generate metadata, test robots.txt, inspect sitemap URLs, prepare redirects, and create clean URL slugs.

Meta Tags Generator Robots.txt Tester Sitemap URL Extractor Redirect Rules Generator URL Slug Generator

Workflow

Work with JSON and APIs

Format JSON, compare payloads, test JSON paths, decode tokens, and convert Base64 values without uploading data.

JSON Formatter / Validator JSON Diff Checker JSON Path Tester JWT Decoder Base64 Encoder / Decoder

Browse by category

Find tools by the job you are doing

Use collections for focused topics, or jump into the searchable directory below for the full catalog.

Docker & Self-hosting

Compose files, env files, volume mappings, reverse proxies, and Linux permission helpers.

DockerComposeProxy

HTTP & Security

Headers, CORS, redirects, status codes, MIME types, and practical website configuration checks.

HeadersCORSRedirects

SEO & Webmaster

Meta tags, robots.txt, sitemap inspection, redirects, slugs, and metadata extraction.

RobotsSitemapsMeta

JSON & Data

Format, validate, diff, query, and convert structured data directly in your browser.

JSONYAMLCSV

Text & Encoding

Regex checks, Markdown previews, Base64, URL encoding, HTML entities, and text transforms.

TextBase64URLs

Network & DevOps

Certificates, CSRs, ports, DNS records, CIDR ranges, and deployment-adjacent diagnostics.

TLSDNSPorts

Tools directory

Searchable browser-only utilities for developers, DevOps, self-hosting, web debugging, SEO, and data formatting.

Time & Date

Cron / Timezone / DST Preview

Preview cron schedules across UTC, local timezones, DST changes, and platform behavior for GitHub Actions, Kubernetes CronJob, and Vercel Cron.

Local-onlyNo uploadcronscheduletimezone

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Time & Date

Unix Timestamp Converter

Convert Unix timestamps to readable local and UTC dates, then turn dates back into seconds or milliseconds.

Local-onlyNo uploadunixtimestamptime

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Data Format

JSON Formatter / Validator

Format, validate, and minify JSON in your browser.

Local-onlyNo uploadjsonformattervalidator

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Data Format

JSON Path Tester

Test basic JSON paths against JSON data in your browser.

Local-onlyNo uploadjsonjsonpathpath

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Data Format

YAML Formatter / YAML to JSON Converter

Format YAML and convert YAML to JSON in your browser.

Local-onlyNo uploadyamlymlformatter

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Data Format

CSV to JSON / JSON to CSV

Convert CSV rows to JSON arrays and JSON arrays back to CSV in your browser.

Local-onlyNo uploadcsvjsonconverter

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Data Format

JSON Diff Checker

Compare two JSON values in your browser and inspect added, removed, and changed fields.

Local-onlyNo uploadjsondiffcompare

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DevOps / Self-host

Docker Compose Preview

Review docker-compose.yml files in your browser and inspect services, ports, volumes, env values, and networks before you wire them into a proxy or VPS.

Local-onlyNo uploaddockercomposedocker-compose

Open toolCopy-ready

DevOps / Self-host

Docker Volume Mapping Helper

Generate Docker volume mappings for docker run and docker-compose in your browser, with bind mount, named volume, read-only, SELinux, and path safety warnings.

Local-onlyNo uploaddockervolumevolumes

Open toolCopy-ready

DevOps / Self-host

Docker Compose Env File Generator

Generate Docker Compose .env files, env_file snippets, and environment blocks in your browser with warnings for duplicate, empty, or sensitive variables.

Local-onlyNo uploaddockercomposeenv

Open toolCopy-ready

DevOps / Self-host

Docker Run to Compose Converter

Convert docker run commands into best-effort docker-compose.yml files in your browser before you extend a self-hosted or VPS stack.

Local-onlyNo uploaddockerruncompose

Open toolCopy-ready

DevOps / Self-host

Docker Compose to Docker Run Converter

Convert docker-compose.yml services into docker run commands in your browser when you need a runnable handoff, a VPS recovery path, or a single-service debug command.

Local-onlyNo uploaddockercomposedocker-compose

Open toolCopy-ready

DevOps / Self-host

Environment Variables Parser / .env Checker

Parse .env files and inspect duplicate keys, empty values, comments, and sensitive variables before Docker, Nginx, or Caddy uses them.

Local-onlyNo uploadenvdotenvenvironment

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DevOps / Self-host

Nginx Reverse Proxy Generator

Generate Nginx reverse proxy config snippets for Docker apps, self-hosted services, WebSocket apps, SSL setups, and header workflows in your browser.

Local-onlyNo uploadnginxreverse proxyproxy

Open toolCopy-ready

DevOps / Self-host

Caddyfile Generator

Generate Caddyfile reverse proxy snippets for Docker services, self-hosted apps, HTTPS sites, compression, security headers, and access logs in your browser.

Local-onlyNo uploadcaddycaddyfilereverse proxy

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DevOps / Self-host

Nginx Config Formatter / Basic Checker

Format Nginx configs and run a basic nginx configuration test for reverse proxy, SSL, syntax, and common config mistakes before you reload.

Local-onlyNo uploadnginxconfigconfiguration test

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DevOps / Self-host

Redirect Rules Generator

Generate redirect rules for Nginx, Caddy, Apache .htaccess, Vercel, and Netlify with 301, 302, wildcard, and path-based snippets.

Local-onlyNo uploadredirectredirect rulesredirects

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DevOps / Self-host

Data Size / Bitrate Converter

Convert data sizes and bitrates, or estimate file size, bitrate, and duration in your browser.

Local-onlyNo uploaddatasizebitrate

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DevOps / Self-host

CHMOD / Linux Permissions Calculator

Convert between chmod numeric and symbolic permissions, inspect common presets, and review practical Linux permission guidance.

Local-onlyNo uploadchmodpermissionslinux

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Network

SSL Certificate Decoder

Decode PEM SSL certificates in your browser and inspect subject, issuer, SANs, validity dates, expiration status, algorithms, and fingerprints before you wire them into a proxy.

Local-onlyNo uploadsslcertificatex509

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Network

CSR Decoder

Decode PEM certificate signing requests in your browser and inspect subject, common name, SANs, public key details, signature algorithm, and fingerprints.

Local-onlyNo uploadcsrcertificate signing requestrequest

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Network

CIDR / Subnet Calculator

Calculate CIDR notation, CIDR blocks, subnet masks, usable IP ranges, broadcast addresses, and address counts in your browser.

Local-onlyNo uploadcidrcidr calculatorcidr notation

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Network

Port Number Lookup

Look up common port numbers and view the service name, protocol, category, usage, and security note.

Local-onlyNo uploadportportsnetwork

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Network

DNS Record Parser

Parse common DNS records locally and inspect hosts, TTLs, values, and warnings in your browser.

Local-onlyNo uploaddnsrecordsparser

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Network

DNS Zone File Parser

Parse DNS zone files in your browser and inspect SOA, NS, A, AAAA, CNAME, MX, TXT, SRV, CAA, PTR records, TTLs, and warnings.

Local-onlyNo uploaddnszonezone file

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Web / SEO

HTTP Status Code Lookup

Look up common HTTP status codes and view their title, category, and short explanation.

Local-onlyNo uploadhttpstatuscode

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Web / SEO

HTTP Headers Parser

Parse HTTP response headers in your browser and inspect caching, proxy, and security header clues in a copyable summary.

Local-onlyNo uploadhttpheadersresponse

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Web / SEO

HTTP Security Headers Checker

Check pasted HTTP response headers for common security headers, risky values, missing protections, and browser-side recommendations.

Local-onlyNo uploadhttpheaderssecurity

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Web / SEO

CORS Header Generator / Checker

Generate CORS headers and config snippets for Nginx, Caddy, Express.js, Cloudflare Workers, and Vercel in your browser, with warnings for wildcard origins, credentials, and preflight issues.

Local-onlyNo uploadcorsheadersaccess-control-allow-origin

Open toolCopy-ready

Web / SEO