Developer tools catalog
66 tools, 9 release checklists, 3 workflows, and 12 skill challenges across 9 canonical categories. Everything runs 100% in your browser — no analytics scripts, no cookies, no third-party requests. We count anonymous visits at the CDN edge only.
Compare & Diff 6
List Comparator
Diff two lists, find unique / common items, duplicates.
Compare & DiffText Diff
Side-by-side diff with word-level change detection.
Compare & DiffJSON Diff
Compare two JSON payloads, ignoring key order.
Compare & DiffDatabase Schema Diff + Migration Helper
Diff two CREATE TABLE schemas and generate ALTER migration hints.
Compare & DiffCSV Join / Merge
Join, merge, and compare CSV files by key.
Compare & DiffCompare Environments
Multi-mode env diff: .env, ConfigMap, YAML, JSON, headers.
Compare & DiffData Formatters & Converters 15
JSON ↔ CSV
Bidirectional conversion with auto-format detection.
Data Formatters & ConvertersJSON ↔ YAML
Convert API responses and configs locally between JSON and YAML.
Data Formatters & ConvertersJSON Formatter
Validate, pretty-print, minify with tree view and secret detection.
Data Formatters & ConvertersYAML Validator
Syntax errors with line/col, multi-doc support.
Data Formatters & ConvertersJSON Patch & Pointer
Apply RFC 6902 patches; resolve JSON Pointers.
Data Formatters & ConvertersJSON Schema Validator
Validate JSON documents against a Draft-7 / Draft-2020 schema.
Data Formatters & ConvertersJSONPath Tester
Extract values using JSONPath expressions.
Data Formatters & ConvertersSynthetic Data Generator from JSON Schema
Generate schema-valid fake data from a JSON Schema (seeded).
Data Formatters & ConvertersSchema Inspector
Infer and inspect the shape of any JSON document.
Data Formatters & ConvertersCSV Viewer
Preview, auto-detect delimiter, trim, export.
Data Formatters & ConvertersJSONL Log Viewer
Inspect newline-delimited JSON logs with field filters.
Data Formatters & ConvertersSQL Formatter
Format SQL with indentation and keyword casing.
Data Formatters & ConvertersCSV → SQL
Generate INSERT / UPSERT statements from CSV.
Data Formatters & ConvertersSQL IN Builder
Build and chunk large SQL IN(...) clauses safely.
Data Formatters & ConvertersSQL Join Builder
Compose multi-table joins with previews.
Data Formatters & ConvertersAPI & Web 15
cURL Converter
Convert curl to Fetch, Axios, Python, Java, Node.
API & WebAPI Debugging Studio
Multi-panel board: parse one cURL or HAR into headers, body, JWT, snippets.
API & WebHAR Sanitizer
Redact secrets, export Postman / cURL / fetch packs.
API & WebHTTP Headers
Parse / edit headers in a grid, detect duplicates.
API & WebURL Parser
Parse URL parts, edit query params in a grid, rebuild.
API & WebRequest Snippet Builder
Build HTTP request snippets for any language.
API & WebOpenAPI Client Snippets
Generate fetch / cURL / Axios calls from OpenAPI.
API & WebOpenAPI Breaking Change Analyzer
Diff two OpenAPI/Swagger specs; classify breaking, risky, safe, doc.
API & WebAPI Contract Test Generator
Generate curl / Jest / Playwright / Postman tests from OpenAPI.
API & WebCORS Debugger / Preflight Simulator
Simulate the browser CORS preflight & request checks; get fixes.
API & WebOpenAPI → Postman
Export full Postman Collection v2.1 from OpenAPI.
API & WebPostman Collection Inspector / Cleaner
Inspect a Postman collection for secrets/dupes; export a cleaned copy.
API & WebXML / XPath / SOAP
Format XML, run XPath, inspect SOAP envelopes.
API & WebXML ↔ JSON
Lossless conversion with attribute handling.
API & WebGraphQL Playground
Validate GraphQL, generate cURL and fetch snippets.
API & WebSecurity & Auth 9
Security Headers
Audit Content-Security-Policy, HSTS, and other security headers.
Security & AuthPII Detector
Find and redact personally identifiable information.
Security & AuthSecrets Scanner
Detect API keys, tokens, and credentials in payloads.
Security & AuthPhishing Link & Email Inspector
Check suspicious links, domains, senders, and raw email headers locally.
Security & AuthJWT Decoder
Decode JWTs locally and verify HMAC signatures with a supplied secret.
Security & AuthJWT & OAuth Toolkit
Sign / verify JWTs (HS/RS/ES), generate PKCE values.
Security & AuthCertificate & PEM
Decode X.509 certs, inspect CSRs, split PEM bundles.
Security & AuthJWK / JWKS / PEM
Convert between JWK, JWKS, and PEM key formats.
Security & AuthWebhook Verifier
Verify Stripe / GitHub / Slack HMAC signatures.
Security & AuthEncode / Decode 4
Base64 Encode / Decode
Encode or decode plain text to Base64.
Encode / DecodeURL Encoder
Encode / decode URL strings and query parameters.
Encode / DecodeEncoding Suite
Base64URL, Hex, Gzip / Deflate, Querystring conversions.
Encode / DecodeString Escape / Unescape
Escape & unescape strings for JSON, JS, SQL, regex, HTML, and more.
Encode / DecodeDevOps & Config 7
.env Converter
Convert between .env, .properties, JSON, bash export.
DevOps & ConfigKubernetes Helper
Generate / validate Deployment, Service, Ingress YAML.
DevOps & ConfigDockerfile Linter
Check for unpinned images, root containers, large COPYs.
DevOps & ConfigKubernetes / Helm Policy Inspector
Lint Kubernetes/Helm YAML against pod-security best practices.
DevOps & ConfigDocker Compose Helper
Generate / validate compose.yaml with healthchecks.
DevOps & ConfigCron Builder
Build cron expressions with guided UI and previews.
DevOps & ConfigCron Analyzer
Explain any cron expression and show next runs.
DevOps & ConfigUtilities 10
Regex Tester
Pattern builder with presets and live match highlighting.
UtilitiesHash Generator
MD5, SHA-1, SHA-256, SHA-512 — hex or Base64.
UtilitiesPassword Generator
Passwords, tokens, test numbers with custom charsets.
UtilitiesUUID Generator
v4, v7, v5 UUIDs with bulk generation and export.
UtilitiesULID, NanoID & KSUID Generator
Generate & decode ULID, NanoID, KSUID, CUID2, and Snowflake IDs.
UtilitiesUnicode & Invisible Character Inspector
Detect and clean invisible, zero-width, bidi, and look-alike characters.
UtilitiesTimestamp Converter
Unix epoch ↔ local / UTC / ISO with shareable links.
UtilitiesTimezone & Date Math
Convert times across timezones, add/subtract durations.
UtilitiesLine Tools
Trim, dedupe, sort, wrap, add prefix / suffix, join.
UtilitiesLorem Ipsum
Generate placeholder paragraphs, sentences, words.
UtilitiesChecklists 9
API Release Checklist
Pre-release checklist: validate the OpenAPI spec, scan sample responses, and confirm versioning.
ChecklistsCSV Reconciliation Checklist
Reconcile source vs. target CSVs during a migration — row counts, keys, and diffs.
ChecklistsDockerfile Review Checklist
Dockerfile review: lint locally, scan for secrets, and confirm image best practices.
ChecklistsEnv Variable Comparison Checklist
Compare environment variables across dev, staging, and production.
ChecklistsHAR Sanitization Checklist
Strip cookies, auth headers, tokens, and PII from a HAR before sharing with support.
ChecklistsJWT / OAuth Review Checklist
JWT / OAuth security review: decode locally and confirm alg, exp, audience, and scopes.
ChecklistsKubernetes Manifest Review
Parse YAML, scan for secrets, and confirm probes, limits, and security context.
ChecklistsOpenAPI Compatibility Checklist
Walk every breaking-change category before bumping your OpenAPI version.
ChecklistsSecrets & PII Pre-check
Pre-release scan for secrets and PII in diffs, logs, and sample payloads.
ChecklistsWorkflows 3
Workflow Gallery
Run browser-only developer workflows to clean, convert, validate, and transform JSON, CSV, JWTs, logs, configs, and URLs. Nothing leaves your browser.
WorkflowsWorkflow Builder
Build, run, and save linear developer workflows in your browser. Chain tools like JSON formatter, Base64, and JWT decoder — nothing is sent to a server.
WorkflowsWorkflow Import
Import a workflow JSON or open a share link. Workflows decode locally in your browser — nothing is uploaded.
WorkflowsChallenges 12
Regex Rescue
Build or choose the right regex to match valid strings and reject invalid ones.
ChallengesAPI Detective
Find the bug in an API request/response: status codes, headers, JWT, CORS, and more.
ChallengesPayload Patch
Pick the right transformation to fix a broken JSON payload.
ChallengesJSONPath Quest
Pick the JSONPath expression that returns the target output.
ChallengesDiff Detective
Spot the meaningful change between two snippets that may break consumers.
ChallengesJWT Heist
Identify what's wrong with a JWT — alg=none, expired, aud mismatch, RS↔HS confusion, and more.
ChallengesCron TimeLock
Pick the cron that matches the intent, or spot the bug in the given cron.
ChallengesCSV Sleuth
Find the missing or duplicated row between two CSV snapshots.
ChallengesDockerfile Watch
Pick the dangerous or non-reproducible line in a Dockerfile snippet.
ChallengesSQL Join Maze
Pick the SQL join that produces the target result set.
ChallengesSecret Hunter
Spot the leaked secret in a config or code snippet.
ChallengesSignature Forensics
Pick the reason this webhook signature verification failed.
Challenges
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