Spoold is a free, privacy-first developer toolbox. Paste into the Magic Box and it detects JSON, HTML, JWT, curl, OpenAPI, CSV, timestamps, and more—then suggests the best tool. You can also browse the full catalog by category. No sign-up is required.

Is Spoold free to use?

Yes. Core tools are free. Heavy work runs in your browser so your payloads are not processed on Spoold servers for formatting, decoding, and similar utilities.

Is my data safe with Spoold?

Tool processing for supported client-side utilities happens in your browser. Encrypted share links are designed so only people with the link can read the payload. Review the Privacy Policy for details on local storage, analytics, support, and third-party services.

What tools are available?

Spoold ships 72+ tools including JSON formatter and diff, JSON Schema validation, YAML and TOML converters, HTML and Markdown preview, JWT decode and sign, OpenAPI/Swagger viewer with curl, GraphQL formatter, curl to code and curl compare, certificate viewer, CSV preview, regex tester, Mermaid, code editor, LLM token utilities, QR codes, and many encoding and text utilities.

Yes. Spoold uses optional support and in-layout promotions for its own tools instead of third-party ad placements. You can support development from the Support Spoold page.

Can I use keyboard shortcuts?

Yes. Press Cmd or Ctrl+K to open tool search, use / from the homepage, and use per-tool shortcuts (shown in the UI) such as jj for JSON and hh for HTML where configured.

Spoold

Paste. Detect. Do.

Guides are written by the Spoold Editorial Team and reviewed for practical accuracy against the related tools. Read our Editorial Policy for update and correction standards.

Practical developer guides

Tutorials that turn messy inputs into working tools.

Short, practical guides for JSON, CSV, Docker Compose, regex, URLs, security checks, and SEO workflows inside Spoold.

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Showing 3 of 39 articles

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R2 Presigned URL CORS: Fix Browser Upload and Download Errors

Cloudflare R2 presigned URLs still need bucket CORS when used from a browser. Learn how to allow PUT, POST, GET, Content-Type, x-amz-* headers, ETag exposure, localhost origins, and preflight requests.

Jun 7, 2026Read

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S3 CORS Policy Generator: Create AWS Bucket CORS JSON for Browser Uploads

Generate AWS S3 CORS policies for browser uploads, public reads, signed downloads, and presigned URLs. Learn CORSRules, AllowedOrigins, AllowedMethods, AllowedHeaders, ExposeHeaders, MaxAgeSeconds, and put-bucket-cors.

Jun 7, 2026Read

Web11 min

CORS Policy for Browser Uploads: S3, R2, Presigned URLs, and ETag

Create a CORS policy for browser uploads to object storage. Learn how origins, PUT/POST methods, Content-Type, x-amz-* headers, preflight OPTIONS, credentials, and ETag exposure work for S3 and Cloudflare R2.

Jun 7, 2026Read

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