Best Free Online Developer Tools to Use in 2026
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
API Key Generator
Generate random API keys with customizable prefix, format, separators, and character sets.
- Home
- Hash & Security
- API Key Generator
Configuration
Generated API Keys
Configure your key and click Generate.
How to Use This API Key Generator
- Choose or type a prefix — Select a preset (Stripe-style, API, etc.) or type your own.
- Select format — Hex (compact), Base62 (case-sensitive), Base64 URL Safe, or mixed alphanumeric.
- Set segments — Number of groups (1–8). More segments = longer, more secure keys.
- Set segment length — Characters per segment (2–16). Total key length = prefix + (segments × segLength) + separators.
- Pick a separator — Underscore, hyphen, dot, colon, or none.
- Toggle uppercase — Optionally force uppercase characters.
- Generate — Creates 5 unique keys at once. Copy individual or all.
API Key Best Practices
-
Use a prefix — Prefixes make it easy to identify key types (e.g.,
sk_live_for secret live keys,pk_test_for publishable test keys). - Minimum 128 bits of entropy — A 32-character hex key provides 128 bits. The default configuration (4 segments × 8 chars = 32 chars hex) meets this.
- Hash stored keys — When storing API keys in your database, hash them (e.g., with SHA-256) so that a data breach doesn't expose raw keys.
- Rotate keys regularly — Rotate API keys every 90–365 days. Invalidate old keys immediately after rotation.
- Use separate keys — Different keys for development, staging, and production environments. Use read-only keys for public-facing clients.
Frequently Asked Questions
How long should an API key be?
Aim for at least 128 bits of entropy. The default config produces a 32-character hex key (128 bits). For higher security, increase segments or segment length. Stripe uses 32-character hex keys for secret keys (sk_live_ + 24 chars).
Is this safe for production API keys?
Yes. This tool uses the Web Crypto API (crypto.getRandomValues()), which is the same cryptographic random number generator used by operating systems and security software. Keys are generated locally in your browser and never sent to any server.
Why use a prefix?
Prefixes help identify key types at a glance. For example, Stripe uses sk_live_ (secret key live), pk_test_ (publishable key test), and whsec_ (webhook secret). Prefixes also allow automated systems to detect and handle different key types.
How is this different from the Random Token Generator?
The Random Token Generator focuses on raw tokens with configurable length and format. The API Key Generator adds prefixes, segments, separators, and uppercase-only mode — features specifically designed for generating production-ready API keys that follow common industry patterns.
Last updated: 17 Aug 2026
Blog
Latest from Our Blog
How to Choose a Hash Algorithm for Data Security
A practical decision guide to choosing the right hash algorithm: MD5, SHA-1, SHA-2, SHA-3, bcrypt, argon2, PBKDF2, and SRI, with comparisons and clear recommendations.
Aug 08, 2026
CSS vs Tailwind CSS: Which One Should You Use?
A thorough, practical comparison of hand-written CSS and Tailwind CSS: learning curve, maintainability, performance, team workflows, and when each approach wins.
Aug 08, 2026
How to Optimize Core Web Vitals for Your Website
Learn practical, step-by-step techniques to improve LCP, INP, and CLS on your website. A developer-focused guide with real measurements and fixes.
Aug 08, 2026
How to Use Base64 Encoding in Real Projects
Learn practical, production-ready ways to use Base64 encoding: data URLs for images, JWT payloads, API tokens, and email attachments, with real code examples.
Aug 08, 2026
AES Encryption Explained: How It Works and Why It Matters
Learn how AES encryption works, the differences between AES-128, AES-192, and AES-256, and how to encrypt and decrypt data online.
Jun 23, 2026