FormatArc

Overview

FormatArc is a web tool centred on a JSON formatter, with conversion between JSON, YAML, CSV, and Markdown. It has no backend — input never leaves the browser. A Chrome extension is also available.

The problem

Pasting JSON into online formatters often means sending sensitive data to a third-party server. Most go-to tools are English-only, and Japanese keywords or error messages return surprisingly thin results.

Key features

• In-browser formatting and conversion across JSON, YAML, CSV, Markdown
• Nothing is sent to a server — even sensitive data stays put
• Syntax errors normalised into readable explanations (ja / en)
• Bilingual SEO with cross-links between tools and blog articles
• A Chrome extension that mirrors the core features

Tech stack

Architecture

Next.js App Router with `output: "export"`, served from S3 + CloudFront provisioned via AWS CDK. GitHub Actions, authenticated to AWS via OIDC, runs lint, build, S3 sync, and CloudFront invalidation on every push to main.

AI's role and boundaries

There is no AI inside the product. Data conversion has exactly one result per input, and inference would only make it less reproducible. AI stays on the production side — keyword research, article drafts, and multilingual error message tuning. Remove it and conversion results are unchanged; only the pace of the surrounding work shifts. Quality is checked against organic search growth, tool retention, and navigation between tools and articles.

Evaluation & Operations

Primary metrics are organic search growth and tool retention. Most tuning effort goes into SEO depth and inter-page navigation between tools and articles.