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Focused utilities for the small tasks that stand between you and your work.
JSON Formatter
Format, validate and minify JSON locally. Keep every number exact.
JWT Decoder
Inspect token headers and claims, without verification.
Regex Tester
Test JavaScript regular expressions, inspect captures and preview replacements locally in a bounded worker.
Base64 Encoder / Decoder
Encode Unicode text or decode Base64 with explicit UTF-8 and alphabet handling.
UUID Generator
Generate one UUID v4 or a fresh batch with secure browser randomness.
Unix Timestamp Converter
Convert seconds, milliseconds and calendar times with explicit UTC or local interpretation.
URL Encoder / Decoder
Percent-encode a URL component or decode it back to text, without opening a URL.
cURL Converter
Convert a cURL command to fetch, Axios, Python or PHP locally, without executing a request.
JSON → TypeScript
Infer TypeScript interfaces or aliases from JSON examples, with optional fields and predictable unions.
LLM Token Counter
Estimate prompt tokens locally with clear accuracy labels and model-specific tokenizer disclosures.
LLM Cost Calculator
Estimate model costs with explicit assumptions.
Context Window Calculator
Check input, output reserves and remaining model context locally.
AI Tool Schema Builder
Build nested JSON tool schemas for OpenAI, Anthropic and Gemini locally.
MCP Config Validator
Check MCP client JSON, host compatibility and security observations locally.
MCP Config Generator
Create host-specific STDIO and HTTP configurations locally, with credential guidance.
MCP Tool Schema Validator
Validate MCP-native tool definitions and JSON Schema 2020-12 structure locally.
MCP Config Converter
Convert MCP client configurations between verified host formats with explicit loss warnings.
JSON Validator
Check strict JSON syntax, locate errors and identify ambiguous duplicate keys without rewriting your data.
JSON ↔ YAML Converter
Convert JSON and YAML 1.2 locally with explicit direction, precision checks and clear unsupported-feature errors.
JSON Schema Generator
Infer a Draft 2020-12 schema from JSON examples, with observed required fields, nullable values and explicit settings.
JSON Diff
Compare JSON values semantically with exact numbers, meaningful paths and ordered arrays, ignoring object key order.
Cron Expression Builder
Build five-field Unix cron schedules, check expressions and preview upcoming runs in an explicit timezone.
Hash Generator
Generate SHA-256, SHA-384 and SHA-512 hashes of UTF-8 text locally with browser Web Crypto.
Text / Code Diff
Compare text and source code line by line with readable additions, removals and unchanged context.
SQL Formatter
Format SQL locally with explicit dialects, indentation and keyword casing, without executing queries.
LLM API Request Builder
Build OpenAI Responses, Anthropic Messages and Gemini Interactions examples locally, without sending requests or collecting keys.
LLM Structured Output Builder
Build or import a final-response JSON Schema and check a reviewed OpenAI, Anthropic and Gemini compatibility subset locally.
Prompt Cache Calculator
Estimate reusable-prefix cache savings using dated model prices, expected hits and provider-specific write/read behavior.
RAG Chunking Visualizer
Inspect local document chunk boundaries, overlap and duplicated token estimates before building a retrieval pipeline.
Embedding Cost & Vector Storage Calculator
Estimate text embedding cost, compare reviewed Batch rates, and size raw float32 or float16 vectors locally.
Vector Similarity Playground
Compare numeric vectors with cosine similarity, dot product and Euclidean distance without uploads or silent normalization.
RAG Context Budget Planner
Reserve instructions, history, tools, output and safety margin before choosing how many retrieved chunks fit a model.
LLM Batch Cost & Workload Planner
Compare dated Standard and Batch text pricing, savings and request-count job estimates for OpenAI, Anthropic and Gemini.
Prompt Template Playground
Render reusable prompt templates with automatically discovered variables and local token estimates.
LLM Rate Limit & Throughput Calculator
Plan RPM and TPM capacity, traffic growth, utilization and safety headroom using your own account limits.
LLM Evaluation Rubric Builder
Create weighted evaluation criteria, preview manual scores and export a reusable rubric locally.
Prompt Comparison / A-B Analyzer
Compare prompt tokens, input costs, context usage, variables and line differences locally.
LLM Tool Call Debugger
Inspect function-call arguments, schemas and call/result linkage locally for OpenAI, Anthropic and Gemini.
Potential Prompt Injection Scanner
Review untrusted text for static instruction and Unicode signals locally, with explicit false-positive and bypass limitations.
OpenAPI → LLM Tool Schema Converter
Convert OpenAPI JSON or YAML into reviewed LLM and MCP tool definitions locally, with reference limits and explicit conversion warnings.
JSON Schema Compatibility Analyzer
Check JSON Schema structure and reviewed OpenAI, Anthropic, Gemini and MCP compatibility rules locally, with precise diagnostics.
HMAC Generator & Verifier
Generate and verify HMAC-SHA-256, SHA-384 and SHA-512 locally with native Web Crypto.
Content Security Policy Builder & Analyzer
Build and statically analyze Content Security Policy headers with explicit diagnostics and a strict CSP starter.
Subresource Integrity Generator & Verifier
Generate and verify SRI hashes from UTF-8 text or raw local files with native Web Crypto.
CORS Policy Builder & Analyzer
Build and statically analyze CORS response headers locally, with origin, credential and preflight guidance.
JWT / JWS Signature Verifier
Verify compact JWT/JWS signatures locally with an explicit algorithm and supplied public key or secret.
X.509 Certificate Decoder & Inspector
Inspect PEM certificates and local DER files, certificate dates, extensions and SHA-256 fingerprints.
TOTP / HOTP Generator & Verifier
Generate and verify TOTP and HOTP codes locally with Base32 secrets, explicit clocks and bounded verification windows.
PEM ↔ JWK Key Converter & Inspector
Convert RSA and EC keys between JWK, public SPKI PEM and private PKCS#8 PEM locally with sensitive-output safeguards.