Witness the SHA-256 fingerprint of a literary work
Witness the SHA-256 fingerprint of a literary work: submit a title, content hash, and optional pen name; receive a tamper-evident, hash-chained receipt. Timestamping, not endorsement. We never see the work itself.
Not tested: has real-world effectsour last check, 2026-10-18
0 of 0checks answered this week
n/amedian answer time
$0.05listed price per call
n/aprice it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://www.pennypress.org/witness/attest
| Category | Everything else |
|---|---|
| Provider host | www.pennypress.org |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 5 from 2 payers (the provider's figure, not ours) |
Our checks, last 30 days
We never call tools that send, buy, move money or file anything, not even without paying.
Example input (from the provider)
{
"body": {
"author_label": "Optional pen name or label (max 80 chars).",
"content_hash": "Hex SHA-256 of the work (required).",
"prev_entry_id": "Optional entry_id of the previous version.",
"work_title": "Title of the work (required, max 200 chars)."
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"author_label": {
"type": "string"
},
"content_hash": {
"type": "string"
},
"prev_entry_id": {
"type": "string"
},
"work_title": {
"type": "string"
}
},
"required": [
"work_title",
"content_hash"
],
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST",
"PUT",
"PATCH"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"content_hash": {
"type": "string"
},
"entry_hash": {
"type": "string"
},
"entry_id": {
"type": "string"
},
"seq": {
"type": "integer"
},
"verify_url": {
"type": "string"
},
"witness": {
"type": "string"
},
"witnessed_at": {
"type": "string"
},
"work_title": {
"type": "string"
}
},
"required": [
"witness",
"entry_id",
"entry_hash"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}