Give your software APIs for asking people.

Create hosted requests for input, files, approvals, reviews, or human tasks. Fangst returns a URL for the person and sends the structured result back through the API or a signed webhook.

Create a request See the endpoints

Authenticate with a Bearer token.

Every management endpoint requires Authorization: Bearer <FANGST_API_TOKEN>. Keep the token in your software or agent tool configuration. Do not put it in the hosted URL you give to the respondent.

Set the base URL and token for your Fangst service. The local values below match the repository setup.

export FANGST_BASE_URL=http://127.0.0.1:8787
export FANGST_API_TOKEN=dev-api-token

Create the hosted request.

This request asks for a damage description, photos and a date. The idempotency key makes a safe retry return the original response.

curl --fail --silent --show-error \
  -X POST \
  -H "Authorization: Bearer ${FANGST_API_TOKEN}" \
  -H 'Idempotency-Key: claim-clm_92831-intake-v1' \
  -H 'Content-Type: application/json' \
  "${FANGST_BASE_URL}/v1/requests" \
  --data '{
    "title": "Damage report",
    "sender": "Example Insurance",
    "one_shot": true,
    "metadata": {"claim_id": "clm_92831"},
    "fields": [
      {"key": "description", "type": "textarea", "required": true},
      {"key": "photos", "type": "files", "required": true},
      {"key": "date", "type": "date"}
    ],
    "webhook": {
      "url": "https://example.com/fangst",
      "secret": "replace-me"
    }
  }'

Give the returned URL to the person.

The response contains the request id, its status, the hosted URL and the metadata you supplied. Your software or agent sends request.hosted_url through its own email, chat or other available channel.

The person opens that URL, fills in the fields and uploads the files. A respondent does not need a Fangst account.

{
  "request": {
    "id": "req_123",
    "status": "open",
    "title": "Damage report",
    "hosted_url": "http://127.0.0.1:8787/f/…",
    "metadata": {"claim_id": "clm_92831"}
  }
}

Read the submission or receive the webhook.

Poll GET /v1/requests/:id/submissions to list accepted submissions. When a request has a webhook, Fangst also sends submission.completed after the submission and its files have been stored. A webhook requires its signing secret.

Webhook requests include X-Fangst-Delivery-Id, X-Fangst-Timestamp and X-Fangst-Signature. The signature is HMAC-SHA256 over <timestamp>.<exact body>. Delivery retries are recorded, and a terminal failure can be replayed.

POST request share hosted_url person submits poll or webhook

Input and file request endpoints.

Create hosted forms and file requests, read their responses, and inspect or replay webhook delivery. The machine-readable request contract is available as OpenAPI 3.1.

POST/v1/requestsCreate a hosted Request.

GET/v1/requests/:idRead the Request and its hosted URL.

POST/v1/requests/:id/disableClose the Request.

GET/v1/requests/:id/submissionsList its Submissions.

GET/v1/submissions/:idRead a Submission.

DELETE/v1/submissions/:idDelete a Submission and its uploaded files from active storage.

GET/v1/attachments/:id/contentDownload attachment bytes with the Bearer token.

GET/v1/deliveries/:idRead Delivery status and immutable attempts.

POST/v1/deliveries/:id/replayRequeue a terminally failed Delivery.

Approval, review, and human-task endpoints.

Each interaction has its own resource and structured result. AI agents can call these HTTP endpoints directly or use the Fangst MCP tools.

POST/v1/approvalsCreate an approval and receive its hosted URL.

GET/v1/approvals/:idRead its decision and receipt.

POST/v1/approvals/:id/disableClose an approval link.

POST/v1/reviewsCreate a review with existing or generated values.

GET/v1/reviews/:idRead the confirmed or corrected values.

POST/v1/tasksCreate a hosted human task.

GET/v1/tasks/:idRead completion, findings, and evidence.

Forms API File Request API Approval API Review API Human Task API MCP tools

Ask the person. Continue with the result.

Use Fangst from your application or give an authorized AI agent access to the APIs it needs.

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