AI & LLM Tools

21 free tools for working with LLMs — token and cost estimation, prompt engineering, structured output schemas, and RAG/embedding planning. All client-side, no API key required.

21 tools
6 categories
100% client-side

Language & Tokens

Token Counter Estimate token counts and API cost across LLM providers. BPE Tokenizer Heatmap Visualize Byte-Pair Encoding token boundaries and character breakdown. Context Window Visualizer See how much of a model's context window your prompt uses.

Prompt Engineering

Few-Shot Prompt Builder Compose few-shot prompt pairs and monitor token budget allocation. Prompt Differ Compare prompt versions with token and cost impact. Prompt Compressor Cut filler and whitespace to reduce prompt token count. System Prompt Builder Build a structured system prompt from role, tone, and constraints.

Code Generation

JSON Schema Mock Data Generate realistic mock data payloads from JSON Schemas. JSON → Zod/Pydantic Generate Zod or Pydantic schemas from sample JSON. Function/Tool Schema Generator Build OpenAI and Anthropic tool-calling JSON schemas. Tool Schema → OpenAPI Convert OpenAI/Anthropic tool schemas to OpenAPI 3.1 specifications. Structured Output Validator Validate JSON against a JSON Schema, with per-field error paths.

RAG & Embeddings

Vector DB & RAG Sizer Estimate vector RAM, HNSW graph overhead, and storage cost. RAG Chunking Visualizer Visualize text chunking boundaries, token counts, and overlapping segments. Embedding Cost Calculator Estimate embedding and vector storage cost for RAG. RAG Chunking Simulator Preview how a document splits under different chunking strategies.

Security & Privacy

PII & Secret Redactor Scrub emails, keys, and secrets from text before pasting into an LLM.

Cost & Planning

AI SaaS Margin Calculator Model AI SaaS unit economics, token costs, and gross margins across models. Agent Cost Simulator Project the cost of a multi-step agent loop with retries. Model Comparison Matrix Sortable price and context-window comparison across LLMs. LLM Latency & TTFT Model Time-to-First-Token (TTFT), streaming speed, and agent latency.

About the AI & LLM Tools Suite

21 tools for the parts of building with LLMs that don't need a model call themselves — estimating token cost, comparing prompt versions, generating structured-output schemas, simulating RAG chunking, and catching sensitive data before it gets pasted into a chat window. Everything runs in your browser; no API keys, no data leaves your machine.