Shonin is an open source, human-in-the-loop approval API. Send an approval request to any email address and wait for a human decision before your automation continues. Approvers need no account: they just click a link.

All requests must include an Authorization: Bearer <api_key> header, except the /v1/decide/:token links in approval emails, which approvers open and which need no key.

Shonin is MIT licensed. Try the hosted demo at shonin.dev, or run your own copy (see Self-Hosting).

1. Sign in with your email at /login. Your API key is on your dashboard and is emailed to you.
2. Send an approval request. Use your own email as the approver: the hosted demo only sends to your account email.

curl -X POST https://shonin.dev/api/v1/approvals \
  -H "Authorization: Bearer sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "action": "Deploy to production",
    "approver_email": "you@example.com"
  }'

3. Open the email and click Approve, then read the result with the id from the response:

curl https://shonin.dev/api/v1/approvals/APPROVAL_ID \
  -H "Authorization: Bearer sk_your_api_key"

The status field changes from pending to approved or rejected.

Pass your API key as a Bearer token in the Authorization header on every request. Sign in at /login to see your key.

curl -H "Authorization: Bearer sk_your_api_key" \
  https://shonin.dev/api/v1/approvals/APPROVAL_ID

Creates a new approval request and sends an email to the approver with Approve and Reject buttons. Returns immediately. The approval stays pending until the approver decides.

Request body

curl -X POST https://shonin.dev/api/v1/approvals \
  -H "Authorization: Bearer sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "action": "Deploy to production",
    "approver_email": "cto@company.com",
    "context": "PR #247 merged, 3 files changed",
    "webhook_url": "https://yourapp.com/webhooks/shonin"
  }'

{
  "id": "a1b2c3d4-...",
  "status": "pending",
  "created_at": "2026-03-21T18:00:00Z",
  "expires_at": "2026-03-22T18:00:00Z"
}

Returns the current state of an approval. Use this to poll for a decision if you are not using webhooks. Only approvals belonging to the authenticated account are returned.

curl https://shonin.dev/api/v1/approvals/a1b2c3d4 \
  -H "Authorization: Bearer sk_your_api_key"

{
  "id": "a1b2c3d4-...",
  "action": "git push origin main --force",
  "context": "Remote diverged after a rebase",
  "approver_email": "cto@company.com",
  "status": "approved",
  "webhook_url": null,
  "command_type": "git_push_force",
  "risk_level": "DESTRUCTIVE",
  "risk_bullets": [
    "Will overwrite upstream commits",
    "Bypasses branch protection rules"
  ],
  "files": [{ "path": "app/route.ts", "status": "modified" }],
  "expires_at": "2026-03-22T18:00:00Z",
  "decided_at": "2026-03-21T18:45:00Z",
  "created_at": "2026-03-21T18:00:00Z"
}

When an approval has a command_type, the email opens with a risk banner so the approver can see how reversible the action is. If you leave command_type out, Shonin infers it from action when it recognizes commands such as git push --force, git reset --hard, rm, drop table or a migration.

Ask a multiple-choice question instead of a yes or no. The respondent gets an email with one button per option and picks one.

Request body

curl -X POST https://shonin.dev/api/v1/decisions \
  -H "Authorization: Bearer sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "question": "Which environment should we deploy to?",
    "options": [
      { "key": "staging", "label": "Staging" },
      { "key": "prod", "label": "Production" }
    ],
    "respondent_email": "cto@company.com"
  }'

{
  "id": "e5f6a7b8-...",
  "status": "pending",
  "created_at": "2026-03-21T18:00:00Z",
  "expires_at": "2026-03-22T18:00:00Z"
}

Returns the current state of a decision. status is pending or decided, and chosen_key holds the key of the option that was picked.

{
  "id": "e5f6a7b8-...",
  "status": "decided",
  "chosen_key": "prod",
  "decided_at": "2026-03-21T18:45:00Z",
  "expires_at": "2026-03-22T18:00:00Z",
  "created_at": "2026-03-21T18:00:00Z"
}

Set webhook_url on an approval or a decision and Shonin sends a POST with a JSON body once the decision is recorded.

{
  "id": "a1b2c3d4-...",
  "status": "approved",
  "decided_at": "2026-03-21T18:45:00Z"
}

{
  "id": "e5f6a7b8-...",
  "status": "decided",
  "chosen_key": "prod",
  "decided_at": "2026-03-21T18:45:00Z"
}

• The URL must be a public https address. Private and reserved addresses are rejected with a 400 when you create the request.
• Shonin waits 5 seconds for a response, does not follow redirects, and sends each webhook once with no retries.

You never call the decide endpoint yourself. It sits behind the links in the email, and it is built so the code that asks for approval cannot give it.

• The approve and reject links exist only in the email to the approver. The API never returns them, so your code cannot approve its own request.
• Opening a link never decides. It leads to a confirm page, and the decision is recorded only when the approver confirms, which sends a POST. Mail scanners and link previews that open every link cannot decide.
• Links are single-use and expire after 24 hours unless you set expires_in_hours.

All errors return a JSON object with an error field containing a human-readable message.

{ "error": "Invalid API key" }

Error codes

Hosted demo only

The hosted demo is capped to protect a shared email allowance. Self-hosted instances do not apply these limits.

Shonin is MIT licensed and runs on Next.js, Supabase and Resend. A self-hosted instance has no request limits, and it serves this same documentation at /docs.

1. Clone the repository and run npm install.
2. Create a Supabase project and run supabase/schema.sql in its SQL editor.
3. Copy .env.example to .env.local and fill in your Supabase and Resend values. Set EMAIL_FROM_DOMAIN to your verified Resend domain.
4. In Supabase, set your app URL as the Site URL and as a redirect URL so login works.
5. Insert your first API key, then run npm run dev.

The full steps, including the SQL for your first key, are in the README on GitHub.