Free NLP & Developer Tools
A curated collection of fast, practical utilities for NLP, LLM work, and development. No signup required. All processing happens in your browser.
Cost & Tokenization
- Tokenizer Visualizer See how text gets tokenized by different models
- Token Counter Count LLM tokens and view context usage
- Prompt Cost Estimator Calculate API costs for GPT-4, Claude, and others
- Context Window Calculator Check remaining context and prevent overflow
- Prompt Diff Tool Compare prompts and see token count changes
- Temperature & Top-K Explainer Learn about LLM sampling parameters
Data & Training
- BERT Fine-tuning Calculator Estimate training time and GPU costs
- Prompt Template Generator Build structured prompts with templates
- EDA Text Augmenter Generate augmented text samples
- Text Preprocessing Pipeline Clean and prepare text data for NLP
- Class Balance Analyzer Detect imbalance and calculate class weights
About PromptUtils
PromptUtils is a free, open-source collection of NLP and LLM tools built for developers and researchers. Whether you're optimizing API costs, fine-tuning transformer models, creating training datasets, or understanding prompt behavior, our tools eliminate friction from common workflows. Every tool runs entirely in your browser—your data never leaves your machine.
Common Workflows
- Cost Optimization: Calculate LLM API spend across GPT-4, Claude, Gemini, and other providers
- Model Training: Estimate BERT fine-tuning costs, GPU hours, and training time
- Prompt Engineering: Build structured prompts, test variations, compare token counts
- Data Augmentation: Generate training data variations using EDA techniques
- NLP Pipelines: Tokenize text, preprocess data, analyze class balance
- Developer Tasks: Manage timestamps, cron schedules, JSON validation, regex testing
Why PromptUtils
- Always Free – No premium plans, no paywalls, no signups
- Privacy-Respecting – Browser-based processing; your data never touches our servers
- Zero Dependencies – Fast, lightweight, built with vanilla JavaScript
- Developer-Focused – Designed by engineers for engineers (keyboard shortcuts, quick actions)
- Continuously Updated – Following latest LLM pricing and models
- Fully Responsive – Optimized for desktop, tablet, and mobile