Upload and Share via StableUpload

Upload any local file to S3-backed cloud storage via x402 micropayments. Returns a public URL. No API keys needed.

Setup

See [rules/getting-started.md](rules/getting-started.md) for installation and wallet setup.

Quick Reference

Default tiers expire after 6 months; short-* tiers after 7 days. short-5gb is for file uploads only (not sites).

Workflow

1. Check wallet balance

npx agentcash@latest balance

Ensure sufficient USDC balance for the chosen tier. If balance is low and the user needs funding details, run npx agentcash@latest accounts to get deposit links and wallet addresses.

2. Determine the tier

Pick the smallest tier that fits the file. Check file size first with ls -la or wc -c. Use a short-* tier when the file only needs to live for 7 days — they cost a fraction of the 6-month tiers.

3. Buy the upload slot

npx agentcash@latest fetch https://stableupload.dev/api/upload -m POST -b '{"filename": "report.pdf", "contentType": "application/pdf", "tier": "10mb"}'

Parameters:

• filename — name for the uploaded file (required)
• contentType — MIME type (required, advisory for browser)
• tier — "10mb", "100mb", "1gb", "short-10mb", "short-100mb", "short-1gb", or "short-5gb" (required)
• policyTtlSeconds — optional upload URL expiration in seconds, 60–86400; use longer TTLs only when reserving an output slot for a downstream service

Response:

{
  "uploadId": "k7gm3nqp2",
  "uploadUrl": "https://f.stableupload.dev/k7gm3nqp2/report.pdf?t=...",
  "uploadMethod": "put",
  "uploadUrlExpiresAt": "2026-08-19T01:00:00.000Z",
  "publicUrl": "https://f.stableupload.dev/k7gm3nqp2/report.pdf",
  "expiresAt": "2027-02-19T00:00:00.000Z",
  "maxSize": 10485760,
  "curlExample": "curl -X PUT ..."
}

4. Upload the file via curl

Use Bash to PUT the file to the returned uploadUrl:

curl -s -X PUT "<uploadUrl>" -H "Content-Type: <mime>" --data-binary @/absolute/path/to/file

Critical: Use --data-binary (not -d) to preserve binary content. Use the absolute path.

The response includes a ready-made curlExample. If uploadMethod is "post", upload a multipart form to postUrl with postFields instead of a PUT.

5. Share the public URL

Present the publicUrl to the user. This URL is publicly accessible immediately and remains live for the tier's retention window (6 months for default tiers, 7 days for short-* tiers) — see expiresAt.

Common MIME Types

Listing Previous Uploads

To list uploads for the current wallet:

npx agentcash@latest fetch https://stableupload.dev/api/uploads

Get Upload Details

npx agentcash@latest fetch https://stableupload.dev/api/download/k7gm3nqp2

Key Details

• No API keys required — payment is the authentication
• Upload URLs expire — see uploadUrlExpiresAt in the response; upload promptly, or set policyTtlSeconds (60–86400) at purchase to extend
• Public URLs last the tier's retention window from purchase date — 6 months for default tiers, 7 days for short-* tiers
• Any file type accepted — contentType is advisory for the browser, not a restriction
• S3-backed — files stored on AWS S3 with public read access
• Discovery endpoint: npx agentcash@latest discover https://stableupload.dev if you need to verify endpoints

Common Patterns

Upload a file the user just created: Skip discovery, go straight to wallet check + buy slot + upload.

Upload multiple files: Buy separate slots for each file. Slots can be purchased in parallel but uploads must use the correct uploadUrl for each.

User asks to "share" or "send" a file: Upload it and present the public URL. The URL can be shared anywhere.

Host images for emails: Upload the image, then reference the publicUrl in email HTML:

<img src="https://f.stableupload.dev/abc/photo.png" alt="Photo" />

Static Site Hosting

Host static sites (HTML/CSS/JS) with custom domains and automatic HTTPS.

Deploy a Site

1. Buy a site slot (paid, tier-based):

npx agentcash@latest fetch https://stableupload.dev/api/site -m POST -b '{"filename": "my-site.zip", "tier": "100mb"}'

Returns {uploadId, uploadUrl}.

2. Upload the zip:

curl -X PUT "$uploadUrl" -H "Content-Type: application/zip" --data-binary @site.zip

3. Activate the site (SIWX, free):

npx agentcash@latest fetch https://stableupload.dev/api/site/activate -m POST -b '{"uploadId": "..."}'

Returns {siteUrl, fileCount, files}. Site is live at https://{uploadId}.s.stableupload.dev/.

Update an Existing Site

Update for free: PUT /api/site to get a new upload URL, upload the new zip, then activate.

npx agentcash@latest fetch https://stableupload.dev/api/site -m PUT -b '{"uploadId": "...", "filename": "my-site.zip"}'

Then upload the new zip and call activate again.

Custom Domain

1. Preview the required DNS records (free, no auth):

npx agentcash@latest fetch "https://stableupload.dev/api/site/domain/preview?hostname=www.example.com"

Returns {hostname, dnsRecords}. Set these DNS records before attaching for instant SSL.

2. Attach the domain:

npx agentcash@latest fetch https://stableupload.dev/api/site/domain -m POST -b '{"uploadId": "...", "hostname": "www.example.com"}'

Creates the TLS cert and routes the hostname. Check status:

npx agentcash@latest fetch "https://stableupload.dev/api/site/domain/status?uploadId=..."

Poll until ssl is "active".

Detach a domain:

npx agentcash@latest fetch https://stableupload.dev/api/site/domain -m DELETE -b '{"uploadId": "...", "hostname": "www.example.com"}'

Renew a Site

npx agentcash@latest fetch https://stableupload.dev/api/site/renew -m POST -b '{"uploadId": "...", "count": 4}'

Extends the site by count x the original tier's retention window (e.g. 4 x 6 months on a default tier). Price = tier price x count ($0.005–$20.00).

Notes

• Max 500 files per site
• Tier limit applies to uncompressed size
• Sites support all tiers except short-5gb; POST /api/site takes filename and tier only (no contentType)
• Custom domains get automatic HTTPS via Cloudflare

Error Handling

• Insufficient balance: Run npx agentcash@latest accounts to show deposit links and wallet addresses
• File too large for tier: Suggest the next tier up
• Upload URL expired: Buy a new slot (the previous payment is non-refundable)
• curl fails: Verify the file path exists and the uploadUrl is correctly quoted