{"slug": "i-built-6-free-developer-tools-for-ai-apis-cron-docker-and-self-hosting", "title": "I Built 6 Free Developer Tools for AI APIs, Cron, Docker, and Self-Hosting", "summary": "The article describes six free, browser-based developer tools created by the author to solve common friction points, including an AI prompt cost calculator, a cron expression generator, a self-hosted software alternatives guide, a Docker deploy generator, a voice AI pricing calculator, and an AI agent safety checklist. All tools require no login, API keys, or tracking, as they run entirely client-side as static React apps built with Vite and Tailwind CSS. The author is also working on additional tools and invites feedback on other developer resources that users frequently need to search for.", "body_md": "I keep running into the same friction points: \"How much will this prompt cost on GPT-4o vs Claude?\", \"What's the cron syntax for every Monday at 9am?\", \"Is there an open-source alternative to Notion I can self-host?\"\nI got tired of Googling each time, so I built a set of free tools that solve these problems. No login, no API keys, no tracking — everything runs in your browser.\nHere's what each one does.\nPaste any prompt and instantly see the cost across 10 AI models: GPT-4o, GPT-4o Mini, o3, o4-mini, Claude Sonnet 4, Claude Haiku 4, Gemini 2.5 Pro, Gemini 2.5 Flash, Llama 4 Maverick (via Groq), and DeepSeek R1.\nIt uses tiktoken for exact OpenAI token counts and estimates for other models (~4 chars/token for English, ~1.5 for Chinese). You can adjust monthly call volume and expected output tokens to see projected monthly costs.\nTry it: AI Prompt Cost Calculator\n161 cron expressions covering every common pattern. Each one comes with a plain-English explanation and the next 5 run times.\nSome examples:\n*/5 * * * *\n— Every 5 minutes0 * * * *\n— Every hour0 9 * * 1\n— Every Monday at 9:00 AM0 0 1 * *\n— First day of every monthThere's also a builder mode where you select the schedule and it generates the expression for you.\nTry it: Cron Expression Generator\n36 popular SaaS tools, each with open-source alternatives you can self-host. Some examples:\nEach alternative has a feature comparison and a link to its Docker deployment config (see tool #4).\nTry it: Self-Hosted Alternatives\nOne-click Docker Compose configs for 30 self-hosted applications. Copy, edit the environment variables, and run docker compose up -d\n.\nEach config includes:\nTry it: Docker Deploy Generator\nCompare TTS (text-to-speech) and STT (speech-to-text) pricing across 6 providers: OpenAI, ElevenLabs, Deepgram, AssemblyAI, Google Cloud, and Azure.\nEnter your expected monthly character volume and see costs for each provider side by side. There are also preset buttons for common volumes (100K, 1M, 5M, 10M characters/month).\nThis was born out of my own frustration trying to compare voice AI pricing — each provider uses different pricing units (per character, per 15 seconds, per minute) making direct comparison painful.\nTry it: Voice AI Pricing Calculator\n18 items across 8 categories for anyone building production AI agents:\nEach item has a severity level (critical/warning/info) and an explanation of why it matters. Check items off as you go — your progress is saved in localStorage.\nTry it: AI Agent Safety Checklist\nAll 6 tools are static React apps built with Vite and Tailwind CSS. No backend, no database, no user accounts. Everything runs client-side.\nThe entire collection lives at prompt-cost-calculator-ten.vercel.app with 240 pages total (mostly from the cron generator and its long-tail expressions).\nI'm working on:\nFeedback and suggestions welcome. What developer tools are you always Googling for?", "url": "https://wpnews.pro/news/i-built-6-free-developer-tools-for-ai-apis-cron-docker-and-self-hosting", "canonical_source": "https://dev.to/w932635477bit/i-built-6-free-developer-tools-for-ai-apis-cron-docker-and-self-hosting-g2n", "published_at": "2026-05-23 10:02:38+00:00", "updated_at": "2026-05-23 10:34:35.043439+00:00", "lang": "en", "topics": ["developer-tools", "open-source", "large-language-models", "artificial-intelligence", "products"], "entities": ["GPT-4o", "Claude", "Gemini", "Llama 4", "DeepSeek R1", "Groq", "Docker", "Notion"], "alternates": {"html": "https://wpnews.pro/news/i-built-6-free-developer-tools-for-ai-apis-cron-docker-and-self-hosting", "markdown": "https://wpnews.pro/news/i-built-6-free-developer-tools-for-ai-apis-cron-docker-and-self-hosting.md", "text": "https://wpnews.pro/news/i-built-6-free-developer-tools-for-ai-apis-cron-docker-and-self-hosting.txt", "jsonld": "https://wpnews.pro/news/i-built-6-free-developer-tools-for-ai-apis-cron-docker-and-self-hosting.jsonld"}}