FREE ONLINE TOOLS
Developer Tools
Developer tools for APIs, code, encoders, formatters, regex, HTTP, shells, agent sandboxes, context packs, and debugging. The listed tools are indexable, linked from FastTool hubs, included in sitemap, and exposed in machine-readable discovery files.
PUBLIC DEVELOPER INDEX
16 Developer tools
A* Pathfinding Terrain 3D Lab Developer
Visualize A* pathfinding over a 3D terrain grid with obstacles, explored frontier, path cost, heuristic diagnostics, search ledger CSV, SVG map, Markdown brief and JSON receipt.
Open toolAPI Cost Shock Simulator Cost Heatmap
Stress test API or AI usage cost with request volume, token size, cache hit rate, growth shocks, budget guardrails, heatmap SVG, CSV ledger, Markdown plan and JSON receipt.
Open toolAPI Deprecation Blast Radius Planner Developer
Paste API deprecation notices, endpoint usage and migration constraints to generate a blast-radius ledger, migration waves, customer email, shim spec, test plan, runbook, SVG and JSON receipt.
Open toolBase64 Encoder and Decoder Developer
Encode text or files to Base64, decode Base64 back to readable text where valid, inspect byte size, and copy the browser-generated result.
Open toolFeature Rollout Blast Radius Simulator Developer
Plan staged feature, AI-tool or product rollouts with blast-radius rings, guardrail pressure, stop gates, rollback actions, SVG, CSV, Markdown runbook and JSON receipt.
Open toolJSON Formatter and Validator Developer
Format, minify and validate JSON in the browser, inspect a tree view, catch line-level errors, then copy or download clean JSON output.
Open toolJSON Validator with Error Location Developer
Validate JSON in the browser, find syntax errors, inspect parsed structure, compare formatted output, and copy a clean validated result.
Open toolJWT Debugger Developer
Decode JWT header and payload in the browser, inspect claims, expiry and algorithm fields, then copy a redacted debug summary.
Open toolOpen Source License Contamination Firewall License Firewall
Paste dependency, SBOM or license inventory to find GPL, AGPL, LGPL, SSPL, Commons Clause, unknown license and NOTICE risks before release. Export SVG, CSV, memo, YAML and JSON receipt.
Open toolRAG Chunk Quality Scorer Developer
Score RAG chunks for coherence, size, query coverage, overlap risk and retrieval usefulness, then export a preflight receipt.
Open toolRegex Tester Developer
Test regex patterns against sample text, inspect matches and capture groups, try replace mode, and use a quick pattern cheatsheet.
Open toolRegex to English Translator Developer
Explain a regular expression in plain English, break down anchors, groups and quantifiers, test sample text, and copy a safer explanation.
Open toolUUID Generator Developer
Generate UUID v4 values in bulk, switch formats, validate existing IDs, copy results, and download a text list from the browser.
Open toolXML to JSON Converter Developer
Convert XML to JSON in the browser, preserve attributes where possible, inspect nesting, handle CDATA notes, and copy structured JSON output.
Open toolYAML to JSON Developer
Convert YAML to JSON or JSON to YAML, catch indentation errors, preserve nested arrays, preview the result, then copy or download clean config output.
Open toolYAML Validator and Formatter Developer
Validate YAML in the browser, format indentation, convert YAML to JSON, catch syntax errors, and copy clean structured output.
Open toolQuality boundary
Use these tools for browser-first drafts, calculations, receipts, and exportable artifacts. For money, safety, legal, medical, regulated, or production-critical decisions, verify the output before acting.