free tools

Free developer tools. Less friction, more building.

JSON, Supabase, SEO, legal templates and SaaS planning — free, no sign-up. Every tool opens on a working example.

JSON

4 tools

JSON diff

Compare two JSON values structurally. See added, removed and changed paths, ignoring object key order. Free, no sign-up, entirely in your browser.

JSON to TypeScript

Generate TypeScript types, Zod validators and JSON Schema from a JSON sample. Merge array shapes and optional fields. Free, no sign-up, browser only.

JSON formatter

Format, minify and validate JSON in your browser. Choose two or four spaces, copy the result or download it. Free, no sign-up and no JSON uploads.

JSON ↔ CSV, YAML & XML

Convert JSON to CSV, YAML or XML and back in your browser. Move Next.js configs and Supabase samples locally with explicit format limits. Free, no sign-up.

Supabase

9 tools

Supabase JWT decoder

Decode a JWT locally and inspect Supabase role, aal, amr, metadata and expiry. Understand auth.uid() and auth.jwt() in RLS. Free, no sign-up.

PostgreSQL SQL formatter

Format PostgreSQL queries, Supabase policies and PL/pgSQL function definitions locally. Check basic syntax without running SQL. Free, no sign-up.

Next.js env & secrets generator

Generate browser-random secrets and a Next.js env template for Supabase and Stripe. Separate NEXT_PUBLIC_ values from server secrets. Free, no sign-up.

Supabase pricing calculator

Estimate Supabase monthly costs for MAU, database, storage, egress, edge functions and compute. Compare dated Free, Pro and Team rates. Free, no sign-up.

Supabase RLS checker

Check Supabase SQL for missing RLS, missing policies, possible recursion, user-data exposure, tenant keys and unsafe definer functions. Free, browser only.

Vercel & Supabase cron generator

Build and explain cron in your browser. Preview local execution times, export vercel.json in UTC or Supabase pg_cron SQL. Free, no sign-up.

CSV / JSON to Supabase seed SQL

Convert CSV or JSON into PostgreSQL INSERT seeds for Supabase. Review types, UUID defaults, escaping and ON CONFLICT DO NOTHING. Free, no sign-up.

Postgres cheat sheet for Supabase

Search PostgreSQL data types, RLS policies, functions, indexes and SaaS queries. Practical uuid, timestamptz and jsonb examples for Supabase. Free, no sign-up.

Postgres playground

Run PostgreSQL SQL locally with PGlite. Try JSONB and RLS using a simulated auth.uid(). Load the engine on demand; no SQL uploads. Free, no sign-up.

Developer

13 tools

Base64 encode / decode

Encode and decode Base64 text and files, create image data URIs and use URL-safe encoding. Recognize JSON and JWTs. Free, no sign-up, browser only.

Markdown editor & table generator

Edit Markdown with a live preview, create tables and start from README.md, AGENTS.md, CLAUDE.md or llms.txt templates. Free, no sign-up, browser only.

Unix timestamp converter

Convert epoch seconds, milliseconds and ISO dates in your browser. Inspect time zones and PostgreSQL timestamptz for Next.js + Supabase. Free, no sign-up.

Text & code diff checker

Compare Next.js code, Supabase migrations or text locally. Review exact line changes side by side or inline, without uploading files. Free, no sign-up.

URL encoder, decoder & parser

Encode, decode and parse Next.js callbacks or Supabase URLs in your browser. Inspect query parameters, duplicates and Unicode. No uploads, free, no sign-up.

JavaScript regex tester

Test JavaScript regex on Next.js routes or Supabase text locally. Highlight matches, inspect capture groups and replace with a worker timeout. No uploads.

UUID v4 / v7 & ULID generator

Generate UUID v4, v7 and ULID batches locally for Next.js and Supabase fixtures. Validate UUID format and inspect v7 timestamps. No uploads, no sign-up.

YAML validator & formatter

Validate YAML 1.2, find errors by line and format configuration in your browser. Preserve comments and anchors for Next.js workflows. Free, no sign-up.

Hash, HMAC & bcrypt generator

Generate MD5, SHA-1, SHA-256, SHA-512, HMAC and bcrypt locally. Verify test bcrypt hashes and choose cost. No values leave the browser. Free, no sign-up.

HTTP status codes for Next.js

Search HTTP status codes with RFC meanings and Next.js route handler examples. Know when to use JSON, redirects or an empty response. Free, no sign-up.

DNS lookup & propagation

Look up A, AAAA, CNAME, MX, TXT, NS and CAA records. Compare Cloudflare and Google DNS answers directly from your browser. Free, no sign-up.

SPF, DKIM & DMARC checker

Inspect email TXT records, expand SPF includes against the 10-lookup limit, validate DMARC syntax and generate provider records. Free, no sign-up.

AGENTS.md / CLAUDE.md / .cursorrules generator

Generate AGENTS.md, CLAUDE.md or .cursorrules for Next.js and Supabase. Include RLS, Zod, migrations, auth, payments and tests. Free, no sign-up.

Technical SEO

4 tools

Schema markup generator & validator

Generate and locally check JSON-LD for software, products, FAQs, organizations and breadcrumbs. Browser validation of pasted markup. Free, no sign-up.

XML sitemap & Next.js sitemap generator

Generate sitemap.xml and Next.js app/sitemap.ts from a route list. Validate pasted XML and extract URLs locally. Free, no sign-up, no website crawl.

Meta tag & Next.js metadata generator

Create Next.js metadata and HTML title, description, canonical, Open Graph and Twitter tags. Preview Google snippets and social cards. Free, no sign-up.

Robots.txt generator & AI bot tester

Generate robots.txt and Next.js app/robots.ts locally. Test URLs for a crawler token and review dated official AI bot sources. Free, no sign-up.

Legal

4 tools

SaaS privacy policy generator

Draft a SaaS privacy policy with a provider inventory read from saascode's live catalog. Editable Markdown templates, free, no sign-up. Not legal advice.

Cookie policy & Next.js consent banner

Draft a cookie inventory and export a Next.js consent provider with optional categories off by default. Free, no sign-up. Template only, not legal advice.

SaaS legal document templates

Draft a refund policy, DPA, NDA, accessibility statement, impressum or DMCA policy with distinct clauses. Free Markdown templates. Not legal advice.

SaaS terms, EULA, disclaimer & AUP

Draft SaaS terms and conditions, EULA, disclaimer and AUP locally. Review subscriptions and software use boundaries. Free, no sign-up; not legal advice.

Planning

17 tools

SaaS SWOT analysis generator

Fill a SaaS SWOT worksheet or seed it from a curated public Genesis idea with field provenance. Export Markdown and PNG, free, no sign-up.

SaaS development cost calculator

Estimate what a SaaS costs to build, from scratch or on a starter kit: measured screens and tables, a public wage and ISBSG effort ranges. Free, no sign-up.

SaaS idea generator

Explore real SaaS startup ideas from the public Genesis bank. Filter a live snapshot by category and build size, then read the evidence. Free, no sign-up.

NPS, CES & SaaS health calculator

Calculate NPS from counts or a survey CSV locally. Inspect CES direction and a custom SaaS health score with visible formulas. Free, no sign-up.

SaaS payment fee calculator

Estimate Stripe, Creem, Paddle, Lemon Squeezy and Polar fees from dated official rates. Choose supported payment cases and see net proceeds. Free, no sign-up.

LLM cost calculator for SaaS

Estimate prompt and monthly text-token costs using the live public OpenRouter models API. Browser cache, retrieval date and visible API failures. Free, no sign-up.

Customer lifetime value for SaaS

Calculate SaaS customer lifetime value, LTV:CAC and payback from monthly ARPA, gross margin, customer churn and CAC. Visible formulas. Free, no sign-up.

SaaS lean canvas generator

Edit a SaaS lean canvas, business model canvas or value proposition canvas locally. Export complete notes as Markdown or PNG. Free, no sign-up.

Bulk domain availability checker

Check SaaS domain names in .com, .ai, .io, .dev and .app with direct registry RDAP. See taken, likely available or unknown. Free, no sign-up.

Startup & SaaS name generator

Generate SaaS startup names from roots, suffixes, blends and get/use prefixes. Set a length and check five domain extensions with RDAP. Free, no sign-up.

SaaS launch UTM builder

Build and parse campaign URLs for Product Hunt, X, LinkedIn, newsletters and ads. Catch uppercase tags, spaces and duplicate UTMs. Free, no sign-up.

Interactive SaaS launch checklist

Plan a SaaS launch across product, security, SEO, legal, payments, analytics and launch channels. Save locally and export Markdown. Free, no sign-up.

Editable SaaS pitch deck outline

Draft a 10–12 slide SaaS pitch deck outline with prompts for problem, product, traction, market, team and the ask. Export Markdown. Free, no sign-up.

SaaS business plan generator

Write a SaaS business plan in eight editable sections. Import optional public Genesis excerpts with field provenance. Export Markdown. Free, no sign-up.

SaaS pricing calculator & plan builder

Build monthly and annual SaaS plans, calculate discounts, set features and limits, and export JSON or a verified Base plans SQL seed. Free, no sign-up.

Product Hunt launch kit

Draft a Product Hunt tagline within 60 characters, structure your maker comment and track a launch-day checklist. Export Markdown. Free, no sign-up.

Startup equity, SAFE & vesting calculator

Model dilution by round, one post-money SAFE with cap and discount, a simple cap table and 4-year vesting. Formulas visible. Free, no sign-up.

Individual legal documents

6 tools

Refund policy

Eligibility, exclusions, request handling and subscription cancellation. Template only, not legal advice.

Data processing agreement

Processing instructions, security, subprocessors, incidents and deletion. Template only, not legal advice.

Non-disclosure agreement

Mutual confidentiality, exclusions, permitted disclosure and duration. Template only, not legal advice.

Accessibility statement

An honest account of tested access, known barriers and feedback. Template only, not legal advice.

Impressum

Operator identity, registration, representation and editorial contact. Template only, not legal advice.

Editing and exports stay in your browser. Domain and DNS checks send the queried names directly to public registry or resolver services. URL checks send the public URL to our server for bounded HTML reading. Each tool explains its scope and limitations. Read the tool index as Markdown.