●

KHOTEM — Cryptographic Witness

Data PAYMENT-READY

payment-ready until 2026-09-02

KHOTEM is a cryptographic witness service for AI agents: seal (SHA-256 commitments), attest, verify, timestamp and audit endpoints, plus three paid operational-law documents for agent builders. Direct on-chain USDC payment verification on Base — no facilitator, no accounts, no API keys. Pay per request, then present the settlement txHash in the X-PAYMENT header. Machine-readable via OpenAPI, the Bazaar discovery extension, skill.md, AGENTS.md and llms.txt.

Pay from $0.02 to $0.25 per request in USDC on Base, settled onchain via the x402 protocol, no signup, no API key needed.

listed 2026-08-26 · no on-chain settlement recorded yet

BASE URL https://khotem.com │ WEBSITE https://khotem.com │ ENDPOINTS 8 │ NETWORK Base │ ASSET USDC │ MEMBER SINCE 2026-08-26 │ MONITORED SINCE 2026-08-26

VERDICT

ranking generation 3

solid 75/100 #222 of 253 in Data by measured score

What the score read on this service: status online, 100% uptime 24h (no 30d window yet), 217ms response p95, x402 compliance 13 of 14, $0.02 price against the category, on-chain traction measured. Each of those is measured, and each is published in full below.

The score comes from our own monitoring, never from reviews, operator claims, or a language model: reliability, x402 compliance, price against the category, a deterministic risk flag, and a small on-chain traction term, weighted by ranking generation 3. It is not placement anyone can buy: the paid verify tier is reported beside it and is not one of its inputs. Every component below stays published and read-only.

It is a score inside Data, and only there: price and speed are scored against the whole category field, every listing in it that carries no danger flag, the scored service included, which here means 253 listings, this one among them. That set is wider than the 253 the position above is counted against, because a listing we have measured too little of to rank still sits in the field the price and the speed are normalized over. The same service in a different field would read differently. The same engine answers GET /api/v1/best, and asked for a different pool (the whole directory, or another filter) it returns a different number for this service under this same ranking generation. Neither is more correct: they answer different questions, and the methodology states which is which.

Bands on the 0 to 100 measured score: strong at 93 and above, solid from 75, mixed from 55, weak below 55. Price and speed are scored against the whole category field, every listing in it that carries no danger flag, the scored service included, so the score places a service in its own field.

ALTERNATIVES IN DATA

Other Data services in this directory, ordered by the same measured score. The figures are ours: 30-day uptime from our own probes, 30-day settlement volume read on-chain (a conservative undercount, and null where we cannot measure it, never a zero).

Ranked alternative x402 services in the same category, with band, measured score, 30-day uptime and 30-day on-chain settlement volume
SERVICE	BAND	SCORE	UPTIME 30D	VOL 30D
WebberSites x402 Data API	strong	99	100%	---
AgentFund US Economic, SEC & On-Chain Data	strong	99	100%	---
API Acre	strong	99	99.9%	---
Agent Exchange	strong	99	100%	---
ForgeMesh Utility APIs	strong	99	100%	---

5 of 252 other ranked services in Data · see the whole category

ASSESSMENT

updated 2h ago

The parts the verdict above is computed from, each with its proof. Click any chip. Measured values stay read-only; unknown is honest, and an unknown is never counted as a zero.

reliability 100%

uptime 24h: -
uptime 7d: -
uptime 30d: -
uptime 90d: -
response p95: 217ms
avg response: 217ms
total checks: 1

Measured on the unpaid 402 handshake, not the paid call. A service can 402 correctly and still fail after payment.

compliance C (13/14): EIP-712 domain parameters present on every EVM entry

13 of 14 x402 conformance checks pass; failing: EIP-712 domain parameters present on every EVM entry. Full checklist below.

jump to compliance checklist

signability route not signable

At least one EVM route on this service returns its 402 without the EIP-712 domain parameters (extra.name and extra.version), so a standard x402 client cannot build the signature for that route.

Measured on the last 402 envelope captured from this service. It is a fact about the envelope, not a judgement on the service or its operator.

This is the only conformance check that caps the compliance grade, at C.

jump to compliance checklist

price $0.02 to $0.25 (p74 in Data)

price (min): $0.02
price (max): $0.25
category percentile (min): p74 in Data
category percentile (max): p84 in Data
endpoints / prices: 8 / 5
model: tiered
stability: 100%

risk clean

No deterministic risk flag. Risk fires only on an exact blocklist match, or a reserved-brand name with a mismatched verified payTo. Never from low uptime, a high price, or a model guess.

domain age: 5d
registrar: Registrar of Domain Names REG.RU LLC
hosting: custom
domain created: 2026-08-20

Identity facts, not a risk score.

traction $0.00 30d · 0 buyers

volume 30d: $0.00
buyers 30d: 0
settlements 30d: 0
measured since: --- (start of our harvest window)
last settlement: ---
top buyer share: -
trend 7d vs 30d: -
networks: eip155:8453
volume all-time: $0
settlements all-time: 0
median settlement 30d: -
max settlement 30d: -
settled via: -

Conservative undercount: only USDC settlements via facilitators we measure are counted. A measured floor, not an estimate.

Top buyer share is a concentration signal, not part of the ranking score.

WHAT IT DOES

ai-derived

No AI synthesis has been produced for this service yet.

ENDPOINTS

Service endpoints with HTTP method, path, description, pricing, and network
METHOD	PATH	PRICE	NETWORK	ASSET	402 CHANNEL
GET	/api/attest	$0.02	Base	USDC	header
GET	/api/audit	$0.15	Base	USDC	header
GET	/api/doc/15	$0.10	Base	USDC	header
GET	/api/doc/16	$0.10	Base	USDC	header
GET	/api/doc/17	$0.10	Base	USDC	header
GET	/api/seal	$0.05	Base	USDC	header
GET	/api/thread	$0.25	Base	USDC	header
GET	/api/verify	$0.05	Base	USDC	header

8 endpoints

REQUEST / RESPONSE EXAMPLE

An unpaid request to GET /api/attest returns HTTP 402 with the payment terms. Settle onchain via your facilitator, then retry with the X-Payment header.

// request

curl -i 'https://khotem.com/api/attest'

// 402 response (captured by monitor) · 8 payloads · click to expand

[
  {
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "payTo": "0x7f334804cE89Aa874a95654d8EeF6D4d0916bFb6",
        "amount": "100000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "/api/doc/15",
      "mimeType": "application/json",
      "description": "KHOTEM /api/doc/15"
    },
    "extensions": {
      "bazaar": {
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "type": "object",
              "properties": {
                "queryParams": {
                  "type": "object",
                  "properties": {},
                  "description": "No input — GET returns the document after payment.",
                  "additionalProperties": false
                }
              }
            },
            "output": {
              "type": "object",
              "properties": {
                "example": {
                  "doc": "15",
                  "sha16": "a1b2c3d4e5f60708",
                  "content": "<document 15, markdown>",
                  "payment_seal": "1020304050607080"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  },
  {
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "payTo": "0x7f334804cE89Aa874a95654d8EeF6D4d0916bFb6",
        "amount": "100000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "/api/doc/16",
      "mimeType": "application/json",
      "description": "KHOTEM /api/doc/16"
    },
    "extensions": {
      "bazaar": {
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "type": "object",
              "properties": {
                "queryParams": {
                  "type": "object",
                  "properties": {},
                  "description": "No input — GET returns the document after payment.",
                  "additionalProperties": false
                }
              }
            },
            "output": {
              "type": "object",
              "properties": {
                "example": {
                  "doc": "16",
                  "sha16": "a1b2c3d4e5f60708",
                  "content": "<document 16, markdown>",
                  "payment_seal": "1020304050607080"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  },
  {
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "payTo": "0x7f334804cE89Aa874a95654d8EeF6D4d0916bFb6",
        "amount": "100000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "/api/doc/17",
      "mimeType": "application/json",
      "description": "KHOTEM /api/doc/17"
    },
    "extensions": {
      "bazaar": {
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "type": "object",
              "properties": {
                "queryParams": {
                  "type": "object",
                  "properties": {},
                  "description": "No input — GET returns the document after payment.",
                  "additionalProperties": false
                }
              }
            },
            "output": {
              "type": "object",
              "properties": {
                "example": {
                  "doc": "17",
                  "sha16": "a1b2c3d4e5f60708",
                  "content": "<document 17, markdown>",
                  "payment_seal": "1020304050607080"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  },
  {
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "payTo": "0x7f334804cE89Aa874a95654d8EeF6D4d0916bFb6",
        "amount": "50000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "/api/seal",
      "mimeType": "application/json",
      "description": "KHOTEM /api/seal"
    },
    "extensions": {
      "bazaar": {
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "type": "object",
              "properties": {
                "body": {
                  "type": "object",
                  "properties": {
                    "hash": {
                      "type": "string",
                      "description": "Pre-computed sha256 hex (64 chars)"
                    },
                    "content": {
                      "type": "string",
                      "description": "Content to hash and seal"
                    }
                  },
                  "description": "Provide either content (server hashes and forgets it) or hash (client-side sha256, content never sent)."
                }
              }
            },
            "output": {
              "type": "object",
              "properties": {
                "example": {
                  "note": "content not stored: hashed and forgotten",
                  "proof": "recorded in the KHOTEM ledger; verifiable via /api/attest",
                  "sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
                  "witness": "KHOTEM-SEAL",
                  "timestamp": "2026-08-24T12:00:00.000Z",
                  "seal_stamp": "a1b2c3d4e5f60708",
                  "payment_seal": "1020304050607080"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  },
  {
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "payTo": "0x7f334804cE89Aa874a95654d8EeF6D4d0916bFb6",
        "amount": "20000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "/api/attest",
      "mimeType": "application/json",
      "description": "KHOTEM /api/attest"
    },
    "extensions": {
      "bazaar": {
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "type": "object",
              "properties": {
                "body": {
                  "type": "object",
                  "required": [
                    "ref"
                  ],
                  "properties": {
                    "ref": {
                      "type": "string",
                      "description": "txHash (0x+64 hex) / sha256 (64 hex) / stamp (16 hex) — exact match"
                    }
                  }
                }
              }
            },
            "output": {
              "type": "object",
              "properties": {
                "example": {
                  "entry": {
                    "ts": "2026-08-24T12:00:00.000Z",
                    "event": "seal",
                    "sha256": "e3b0c4…"
                  },
                  "attest": "CONFIRMED",
                  "attest_seal": "a1b2c3d4e5f60708",
                  "payment_seal": "1020304050607080"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  },
  {
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "payTo": "0x7f334804cE89Aa874a95654d8EeF6D4d0916bFb6",
        "amount": "50000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "/api/verify",
      "mimeType": "application/json",
      "description": "KHOTEM /api/verify"
    },
    "extensions": {
      "bazaar": {
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "type": "object",
              "properties": {
                "body": {
                  "type": "object",
                  "required": [
                    "seal"
                  ],
                  "properties": {
                    "seal": {
                      "type": "object",
                      "required": [
                        "root"
                      ],
                      "properties": {
                        "root": {
                          "type": "string",
                          "description": "merkle root hex"
                        }
                      }
                    }
                  },
                  "description": "Session object. All fields except \"seal\" and \"_\"-prefixed are hashed into leaves; seal.root must equal the merkle root."
                }
              }
            },
            "output": {
              "type": "object",
              "properties": {
                "example": {
                  "ok": 1,
                  "total": 1,
                  "results": [
                    {
                      "ok": true,
                      "root": "9f2c…"
                    }
                  ],
                  "verdict": "✓ ALL VERIFIED",
                  "payment_seal": "a1b2c3d4e5f60708",
                  "verdict_seal": "1020304050607080"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  },
  {
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "payTo": "0x7f334804cE89Aa874a95654d8EeF6D4d0916bFb6",
        "amount": "250000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "/api/thread",
      "mimeType": "application/json",
      "description": "KHOTEM /api/thread"
    },
    "extensions": {
      "bazaar": {
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "type": "object",
              "properties": {
                "queryParams": {
                  "type": "object",
                  "properties": {},
                  "description": "No input — GET returns the full document thread after payment.",
                  "additionalProperties": false
                }
              }
            },
            "output": {
              "type": "object",
              "properties": {
                "example": {
                  "mode": "DIRECT",
                  "thread": {
                    "15": {
                      "file": "DOC15.md",
                      "sha16": "a1b2c3d4e5f60708",
                      "content": "<markdown>"
                    }
                  },
                  "payment_seal": "1020304050607080"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  },
  {
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "payTo": "0x7f334804cE89Aa874a95654d8EeF6D4d0916bFb6",
        "amount": "150000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "/api/audit",
      "mimeType": "application/json",
      "description": "KHOTEM /api/audit"
    },
    "extensions": {
      "bazaar": {
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "type": "object",
              "properties": {
                "body": {
                  "type": "array",
                  "items": {
                    "type": "object",
                    "required": [
                      "seal"
                    ],
                    "properties": {
                      "seal": {
                        "type": "object",
                        "required": [
                          "root"
                        ],
                        "properties": {
                          "root": {
                            "type": "string",
                            "description": "merkle root hex"
                          }
                        }
                      }
                    },
                    "description": "Session object. All fields except \"seal\" and \"_\"-prefixed are hashed into leaves; seal.root must equal the merkle root."
                  },
                  "description": "Array of session objects, same shape as /api/verify"
                }
              }
            },
            "output": {
              "type": "object",
              "properties": {
                "example": {
                  "ok": 3,
                  "total": 5,
                  "results": [
                    {
                      "ok": true,
                      "root": "9f2c…"
                    },
                    {
                      "ok": false,
                      "reason": "root_mismatch"
                    }
                  ],
                  "verdict": "✗ TAMPERED",
                  "payment_seal": "a1b2c3d4e5f60708",
                  "verdict_seal": "1020304050607080"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  }
]

OVER TIME

All charts use the 24h selector; each series spans only the dates it has data for. Every series is also served as JSON at /api/v1/services/khotem-cryptographic-witness/price, /scores, /volume and /buyers. On-chain volume and distinct buyers are measured over the service's settlement address and are a conservative undercount (only settlements that reach a measured facilitator are counted). The on-chain series roll up hourly, so the latest day can be up to about an hour behind; distinct buyers are counted per payout address, so a service that settles to more than one address is an upper bound.

UPTIME

24h UPTIME 100%

RESPONSE TIME

AVG RESP 268ms

PRICE (captured 402, USD)

Median across 8 endpoints. Use the selector to isolate one.

SUB-SCORES (uptime + x402 compliance)

checklist grew 11->14 on 2026-07-28; a step here is a metric change, not a regression

VOLUME (on-chain settlement, USD)

DISTINCT BUYERS

COMPLIANCE

13/14 checks pass · grade C · failing: EIP-712 domain parameters present on every EVM entry

last 402 captured 2026-08-26 · last up 2026-08-26

402 payload captured
accepts[] array present
payTo address recoverable
payTo at accepts[0].payTo (conformant shape)
payTo is a valid on-chain address
atomic price declared
atomic price in a sane range
asset (token) address declared
network resolves to CAIP-2
payment scheme declared
served over HTTPS
declares the current x402 version (2)
EIP-712 domain parameters present on every EVM entry
x402 v2 envelope delivered in the payment-required header

SITE PILLARS

homepage reachable
openapi doc
pricing page
llms.txt
robots.txt
terms page

recent checks (10) live · click to expand

TIME STATUS RESP CAUSE

13:18:01 UTC ● OK 218ms

13:02:02 UTC ● OK 240ms

12:46:01 UTC ● OK 187ms

12:30:03 UTC ● SLOW 428ms

12:14:03 UTC ● SLOW 435ms

11:58:02 UTC ● OK 246ms

11:42:01 UTC ● OK 156ms

11:26:02 UTC ● OK 337ms

11:10:01 UTC ● OK 213ms

10:54:01 UTC ● OK 217ms

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status

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RUN THIS SERVICE?

Keep this listing accurate: propose changes to the name, description, website, category or add new endpoints to monitor. Ownership is verified with a domain proof and every change is reviewed manually; measured data stays read-only.

[ update this listing ]

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[ verify this service ($0.25) ]

To request delisting, email info@x402-list.com or update your listing at /services/khotem-cryptographic-witness/update.