New · Prompt cost calculator
Build better AI prompts.
PromptFoo is the fastest way to write, optimize, test, and share prompts across ChatGPT, Claude, Gemini and every model your team already uses.
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Models
Prompt every frontier model.
Model-specific guides, tips, and templates for the 12 models teams actually use in production.
ChatGPT
The general-purpose workhorse for writing, coding, and reasoning.
Claude
The careful, long-context writer for nuanced work.
Gemini
Multimodal reasoning tuned for research and grounded answers.
Grok
Real-time answers with a sharper, less filtered voice.
Perplexity
Answer engine that cites the web.
DeepSeek
Open-weight reasoning model with strong math and code.
Midjourney
The taste-forward image generator for concept art.
Flux
Fast, photoreal image model with excellent prompt adherence.
Sora
Text-to-video with cinematic motion.
Veo
High-fidelity video generation with strong physics.
Llama
The open-weight foundation model that runs anywhere.
Mistral
Efficient European models with strong reasoning.
Qwen
Open multilingual model with excellent Chinese and code.
Tools
A workshop for prompts.
Everyday utilities and AI-powered generators. Free, fast, and no sign-in required.
AI Prompt Generator
Turn a rough idea into a production-ready prompt with role, context, format, and constraints.
Prompt Optimizer
Rewrite an existing prompt to be clearer, tighter, and more likely to get the output you want.
Prompt Improver
Get a critique and an improved version of your prompt with a diff-style explanation.
Prompt Token Counter
Estimate tokens for OpenAI, Anthropic, and Google models before you spend.
Prompt Cost Calculator
Estimate the per-call and monthly cost of a prompt across popular AI models.
Prompt Expander
Turn a one-line prompt into a rich, structured brief.
Prompt Shortener
Compress verbose prompts without losing meaning.
Prompt Rewriter
Rewrite a prompt in a different tone, register, or style.
Prompt Analyzer
Score a prompt on clarity, specificity, and structure.
Prompt Translator
Translate prompts between languages while preserving intent.
Prompt to JSON
Convert a natural-language prompt into a structured JSON schema.
Prompt Cleaner
Remove filler, redundant instructions, and ambiguous phrasing.
Blog Outline Generator
Generate SEO-aware blog outlines from a topic or keyword.
Email Generator
Draft on-brand emails from a short brief.
LinkedIn Post Generator
Write posts that read like a person, not a bot.
YouTube Title Generator
Generate click-worthy, honest video titles.
Meta Description Generator
Write meta descriptions that hit the character limit.
Product Description Generator
Turn features into buyer-focused product copy.
Word Counter
Count words, characters, sentences, and paragraphs instantly.
Case Converter
Convert text between upper, lower, title, sentence, and camel case.
Reading Time Calculator
Estimate reading time by word count and reading speed.
Slug Generator
Turn titles into clean, URL-safe slugs.
Meta Tag Generator
Generate complete meta, Open Graph, and Twitter tags.
Schema Generator
Generate JSON-LD schema for articles, products, FAQs, and more.
Sitemap Generator
Generate an XML sitemap from a URL list.
JSON Formatter
Format, validate, and minify JSON in your browser.
Regex Tester
Test regular expressions with live match highlighting.
UUID Generator
Generate v4 UUIDs in bulk.
Library
Prompts for every job.
Thousands of curated prompts, organized by the work you actually do.
Journal
Field notes on prompting.
Practical writing on prompt engineering, model comparisons, and the workflows behind them.
How to write better AI prompts (a working framework)
Prompt Engineering · 7 min read
How to write better AI prompts (a working framework)
The role-context-task-format-constraints pattern that separates prompts that work from prompts that almost work.
ChatGPT vs Claude vs Gemini in 2026: which one for which job
Comparisons · 9 min read
ChatGPT vs Claude vs Gemini in 2026: which one for which job
A working breakdown of where each frontier model wins in day-to-day use.
Prompt templates that actually scale across a team
Guides · 6 min read
Prompt templates that actually scale across a team
What changes when 'a good prompt' has to survive five teammates and three model upgrades.
FAQ
Common questions.
- What is PromptFoo?
- PromptFoo is a toolkit for building better AI prompts — a prompt generator, optimizer, library, and a set of everyday AI utilities in one place.
- Is PromptFoo free?
- The core tools and library are free. Advanced features and higher usage limits are available on paid plans.
- Which AI models does PromptFoo support?
- PromptFoo supports the major frontier models — including ChatGPT, Claude, Gemini, Grok, DeepSeek, and open-weight models like Llama, Mistral, and Qwen.
- Do I need an API key?
- No. PromptFoo runs the AI-powered tools on our infrastructure so you can start with just an idea.
- Can I save and share my prompts?
- Yes. Create a free account to save prompts, build collections, and share them with a public link.
The prompt engineer's newsletter.
One email a week. New prompts, model updates, and one workflow you can steal.