Developer Tools, Finally Simple.
47+ free, instant-use utilities. No sign-ups, no installs. Just copy your data and go.
All Tools
JSON Schema Generator
Generate JSON Schema from sample data. Auto-detect types and nested structures
Use Tool →CIDR Subnet Calculator
Calculate network address, broadcast, and usable host range from any IP/CIDR
Use Tool →CORS Policy Builder
Generate CORS headers for Nginx, Apache, Cloudflare, Express, and more
Use Tool →Git Command Generator
Generate git commands for branches, commits, rebase, stash, and more
Use Tool →Dummy Data Generator
Generate fake names, emails, addresses, passwords, and test data in JSON/CSV/SQL
Use Tool →AI Prompt Builder
Structure prompts with templates, system instructions, and parameter controls
Use Tool →API Cost Estimator
Estimate token usage and costs for GPT, Claude, Gemini, and other models
Use Tool →Token Counter
Estimate token count and API costs for your text input across popular models
Use Tool →Mortgage Calculator
Calculate monthly payments, total interest, and full amortization schedule
Use Tool →Auto Loan Calculator
Calculate monthly car payments with down payment and trade-in options
Use Tool →WHOIS Lookup
Search domain registration info, registrar, nameservers, and expiry dates via RDAP
Use Tool →ARIN Network Lookup
Search IP ranges, ASN, network ownership, and abuse contacts via RDAP
Use Tool →Why DevToolBox?
⚡ Instant Use
No sign-ups, no installs. Paste your data and get results immediately.
🔒 100% Client-Side
Your data never leaves your browser. No servers, no cookies, no tracking.
💰 Forever Free
All tools are completely free. No premium tiers, no hidden fees.