Sellat proof of existence for one SHA-256
Sellat proof of existence for one SHA-256: anchored on Polygon in the next fast batch (minutes) and attested on Bitcoin through OpenTimestamps; certificate, proof.json and evidence ZIP, verifiable without Sellat.
Answeringour last check, 2026-10-18
1 of 1checks answered this week
964 msmedian answer time
$0.01listed price per call
$0.01price 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://sellat.app/api/v2/proofs
| Category | Everything else |
|---|---|
| Provider host | sellat.app |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 0 from 0 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-18 | valid payment request | 402 | $0.01 | 964 ms |
Example input (from the provider)
{
"body": {
"hash": "<sha256 of the file, 64 hex>",
"metadata": {
"ref": "optional"
},
"name": "contract.pdf"
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"headers": {
"additionalProperties": {
"type": "string"
},
"type": "object"
},
"method": {
"enum": [
"POST",
"PUT",
"PATCH"
],
"type": "string"
},
"pathParams": {
"additionalProperties": {
"type": "string"
},
"type": "object"
},
"queryParams": {
"additionalProperties": {
"type": "string"
},
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}