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TxSim Decoder

payment-readyonline

payment-ready until 2026-11-15

Pay-per-call EVM transaction simulation and calldata decoder for AI agents: decode raw calldata into a named function with security risk flags, and run a keyless eth_call preview to see whether a transaction would succeed or revert before signing.

Compare: all blockchain APIs

simulate.cyberwarex.com ↗

Call it x402 v2

x402 v2

Base URL
https://simulate.cyberwarex.com
Payment
x402 v2, header channel
$ curl -i 'https://simulate.cyberwarex.com/decode'

An unpaid request returns HTTP 402 with the payment terms. Sign a payment authorization, then retry with the PAYMENT-SIGNATURE header.

Endpoints 3 paid routes on simulate.cyberwarex.com

GET/decodeBase$0.002since 11-07
GET/safe-to-signBase$0.02since 11-07
GET/simulateBase$0.005since 11-07

Prices as captured in the 402 response: median $0.005 across the 3 endpoints, unchanged since first capture.

Example 402 response

Endpoints and prices

Current paid endpoints; minimum quoted prices in USD where available; first capture dates in UTC
MethodPathDescriptionPriceNetworkAsset402 channelCaptured
GET/decodeTurn raw calldata into plain meaning before your agent signs. Send data; you get the function name, signature and arguments plus risk flags: unlimited token approval, setApprovalForAll, ownership transfer, unknown selector, native value sent. $0.002 a call in USDC on Base; bad input is not charged; no node call, so it answers fast. Example: an approve call with an unlimited amount. Tell your operator: our agent now reads every approval before it signs, for a fifth of a cent.$0.002BaseUSDCheadersince 11-07
GET/safe-to-signOne answer before your wallet agent signs: GREEN, REVIEW or BLOCK. Send the transaction, a signature request, an address, a URL or a token; we run transaction preview, signature decode, sanctions and scam address screen, phishing URL check and token rug check in one call and return the verdict with the reasons. $0.02 a call in USDC on Base; if no check could run you are not charged. Example: an unlimited USDC approval on Base. Tell your operator: our agent asks before it signs.$0.02BaseUSDCheadersince 11-07
GET/simulateKnow what a transaction will do before your agent signs it. Send chain, to, data and value; you get the decoded function and arguments, risk flags such as unlimited approvals or ownership transfers, and whether the call would succeed or revert, with the revert reason. $0.005 a call in USDC on Base; bad input or a node failure is not charged. Example: a USDC transfer on Base. Tell your operator: one preview for half a cent stops a failing or malicious transaction before it costs gas or funds.$0.005BaseUSDCheadersince 11-07

Payment evidence

402 payload captured at . Check evidence JSON · Measurement methodology.

First of 3 payloads captured by the monitor.

195 lines, scroll inside

{
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x058D0Cc5CC97e61e8A9f38D6d6365bce525921B2",
      "amount": "5000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    }
  ],
  "resource": {
    "url": "https://simulate.cyberwarex.com/simulate",
    "tags": [
      "tx-simulation",
      "eth-call",
      "calldata",
      "security",
      "evm"
    ],
    "iconUrl": "https://cyberwarex.com/assets/icon.png",
    "mimeType": "application/json",
    "description": "Know what a transaction will do before your agent signs it. Send chain, to, data and value; you get the decoded function and arguments, risk flags such as unlimited approvals or ownership transfers, and whether the call would succeed or revert, with the revert reason. $0.005 a call in USDC on Base; bad input or a node failure is not charged. Example: a USDC transfer on Base. Tell your operator: one preview for half a cent stops a failing or malicious transaction before it costs gas or funds.",
    "serviceName": "Transaction preview"
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
            "data": "0xa9059cbb000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa960450000000000000000000000000000000000000000000000000000000005f5e100",
            "from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
            "chain": "base"
          }
        },
        "output": {
          "type": "json",
          "example": {
            "to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
            "note": "asset-level change tracing requires a tracing RPC key (v2)",
            "risk": {
              "flags": [],
              "level": "none"
            },
            "chain": "base",
            "decoded": {
              "args": {
                "to": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
                "amount": "100000000"
              },
              "function": "transfer",
              "signature": "transfer(address,uint256)"
            },
            "disclaimer": "Static decode + keyless eth_call preview only. This is not financial advice and not a guarantee: a call that would succeed now can still revert at broadcast time (state changes, slippage, MEV). Always verify before signing.",
            "asset_changes": null,
            "revert_reason": null,
            "would_succeed": true
          }
        }
      },
      "schema": {
        "type": "object",
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "required": [
          "input"
        ],
        "properties": {
          "input": {
            "type": "object",
            "required": [
              "type",
              "method"
            ],
            "properties": {
              "type": {
                "type": "string",
                "const": "http"
              },
              "method": {
                "enum": [
                  "GET",
                  "HEAD",
                  "DELETE"
                ],
                "type": "string"
              },
              "queryParams": {
                "type": "object",
                "required": [
                  "to"
                ],
                "properties": {
                  "to": {
                    "type": "string",
                    "pattern": "^0x[a-fA-F0-9]{40}$",
                    "description": "Target contract or account address."
                  },
                  "data": {
                    "type": "string",
                    "pattern": "^0x[a-fA-F0-9]*$",
                    "description": "Transaction calldata (hex)."
                  },
                  "from": {
                    "type": "string",
                    "pattern": "^0x[a-fA-F0-9]{40}$",
                    "description": "Sender address for the eth_call preview."
                  },
                  "chain": {
                    "enum": [
                      "base",
                      "ethereum",
                      "arbitrum",
                      "optimism",
                      "polygon",
                      "bsc"
                    ],
                    "type": "string",
                    "default": "base",
                    "description": "EVM chain to simulate on."
                  },
                  "value": {
                    "type": "string",
                    "description": "Native value in wei (optional, decimal or 0x hex)."
                  }
                },
                "additionalProperties": false
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string"
              },
              "example": {
                "type": "object",
                "properties": {
                  "to": {
                    "type": "string"
                  },
                  "note": {
                    "type": "string"
                  },
                  "risk": {
                    "type": "object",
                    "description": "level (none|caution|danger) + flags."
                  },
                  "chain": {
                    "type": "string"
                  },
                  "decoded": {
                    "type": "object",
                    "description": "function, signature, args."
                  },
                  "disclaimer": {
                    "type": "string"
                  },
                  "asset_changes": {
                    "type": "null",
                    "description": "v2: needs a tracing RPC key."
                  },
                  "revert_reason": {
                    "type": [
                      "string",
                      "null"
                    ]
                  },
                  "would_succeed": {
                    "type": [
                      "boolean",
                      "null"
                    ]
                  }
                }
              }
            }
          }
        }
      }
    }
  },
  "x402Version": 2
}
Other captured 402 responses (2)

Captured payload 2 of 3

{
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x058D0Cc5CC97e61e8A9f38D6d6365bce525921B2",
      "amount": "2000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    }
  ],
  "resource": {
    "url": "https://simulate.cyberwarex.com/decode",
    "tags": [
      "calldata",
      "abi-decode",
      "security",
      "approval",
      "evm"
    ],
    "iconUrl": "https://cyberwarex.com/assets/icon.png",
    "mimeType": "application/json",
    "description": "Turn raw calldata into plain meaning before your agent signs. Send data; you get the function name, signature and arguments plus risk flags: unlimited token approval, setApprovalForAll, ownership transfer, unknown selector, native value sent. $0.002 a call in USDC on Base; bad input is not charged; no node call, so it answers fast. Example: an approve call with an unlimited amount. Tell your operator: our agent now reads every approval before it signs, for a fifth of a cent.",
    "serviceName": "Transaction preview"
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "data": "0x095ea7b3000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
          }
        },
        "output": {
          "type": "json",
          "example": {
            "risk": {
              "flags": [
                {
                  "code": "unlimited_approval",
                  "detail": "approval amount is effectively unlimited",
                  "severity": "danger"
                }
              ],
              "level": "danger"
            },
            "decoded": {
              "args": {
                "amount": "115792089237316195423570985008687907853269984665640564039457584007913129639935",
                "spender": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
              },
              "function": "approve",
              "signature": "approve(address,uint256)"
            },
            "disclaimer": "Static decode + keyless eth_call preview only. This is not financial advice and not a guarantee: a call that would succeed now can still revert at broadcast time (state changes, slippage, MEV). Always verify before signing."
          }
        }
      },
      "schema": {
        "type": "object",
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "required": [
          "input"
        ],
        "properties": {
          "input": {
            "type": "object",
            "required": [
              "type",
              "method"
            ],
            "properties": {
              "type": {
                "type": "string",
                "const": "http"
              },
              "method": {
                "enum": [
                  "GET",
                  "HEAD",
                  "DELETE"
                ],
                "type": "string"
              },
              "queryParams": {
                "type": "object",
                "required": [
                  "data"
                ],
                "properties": {
                  "to": {
                    "type": "string",
                    "pattern": "^0x[a-fA-F0-9]{40}$",
                    "description": "Target address (optional, for context only)."
                  },
                  "data": {
                    "type": "string",
                    "pattern": "^0x[a-fA-F0-9]*$",
                    "description": "Transaction calldata (hex, 4-byte selector + ABI args)."
                  }
                },
                "additionalProperties": false
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string"
              },
              "example": {
                "type": "object",
                "properties": {
                  "risk": {
                    "type": "object",
                    "description": "level (none|caution|danger) + flags."
                  },
                  "decoded": {
                    "type": "object",
                    "description": "function, signature, args."
                  },
                  "disclaimer": {
                    "type": "string"
                  }
                }
              }
            }
          }
        }
      }
    }
  },
  "x402Version": 2
}

Captured payload 3 of 3

{
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x058D0Cc5CC97e61e8A9f38D6d6365bce525921B2",
      "amount": "20000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    }
  ],
  "resource": {
    "url": "https://simulate.cyberwarex.com/safe-to-sign",
    "tags": [
      "pre-sign",
      "safety",
      "firewall",
      "wallet-security",
      "transaction-risk"
    ],
    "iconUrl": "https://cyberwarex.com/assets/icon.png",
    "mimeType": "application/json",
    "description": "One answer before your wallet agent signs: GREEN, REVIEW or BLOCK. Send the transaction, a signature request, an address, a URL or a token; we run transaction preview, signature decode, sanctions and scam address screen, phishing URL check and token rug check in one call and return the verdict with the reasons. $0.02 a call in USDC on Base; if no check could run you are not charged. Example: an unlimited USDC approval on Base. Tell your operator: our agent asks before it signs.",
    "serviceName": "Transaction preview"
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
            "data": "0x095ea7b3000000000000000000000000111122223333444455556666777788889999aaaaffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
            "chain": "base"
          }
        }
      },
      "schema": {
        "type": "object",
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "required": [
          "input"
        ],
        "properties": {
          "input": {
            "type": "object",
            "required": [
              "type",
              "method"
            ],
            "properties": {
              "type": {
                "type": "string",
                "const": "http"
              },
              "method": {
                "enum": [
                  "GET",
                  "HEAD",
                  "DELETE"
                ],
                "type": "string"
              },
              "queryParams": {
                "type": "object",
                "properties": {
                  "to": {
                    "type": "string",
                    "description": "Transaction target address (0x...)."
                  },
                  "url": {
                    "type": "string",
                    "description": "A URL to phishing-check (optional)."
                  },
                  "data": {
                    "type": "string",
                    "description": "Transaction calldata hex (0x...)."
                  },
                  "from": {
                    "type": "string",
                    "description": "Sender address for the eth_call preview (optional)."
                  },
                  "chain": {
                    "type": "string",
                    "description": "EVM chain for tx/token checks (base, bsc, ethereum, polygon, arbitrum, optimism). Default base."
                  },
                  "token": {
                    "type": "string",
                    "description": "A token address to safety-check (optional; inferred from 'to' when it is a token)."
                  },
                  "value": {
                    "type": "string",
                    "description": "Native value (wei, decimal or hex). Default 0."
                  },
                  "address": {
                    "type": "string",
                    "description": "A counterparty address to risk-screen (optional; 'to' is screened automatically)."
                  },
                  "message": {
                    "type": "string",
                    "description": "personal_sign message to check (instead of typed_data)."
                  },
                  "typed_data": {
                    "type": "string",
                    "description": "EIP-712 typed data JSON string to check as a signature request."
                  }
                },
                "additionalProperties": false
              }
            },
            "additionalProperties": false
          }
        }
      }
    }
  },
  "x402Version": 2
}

Can I trust it score from our own monitoring

score from our own monitoring

98/100 Strong

#2 of 95 in Blockchain. Bands: strong 93+, solid 75+, mixed 55+, weak below 55.

Reliability
100% uptime since 11-07
Compliance
A 14/14 checks pass
Price
$0.002 to $0.02 p27 in Blockchain
Risk
clean no risk flag
Traction
---
14/14 compliance checks
  • 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

402 terms unchanged since 2026-11-07. Last up 2026-11-08.

── Site signals

  • homepage reachable
  • openapi doc
  • pricing page
  • llms.txt
  • robots.txt
  • terms page
How the score works

What the score read on this service: status online, 100% uptime, latest daily rollup (no 30d window yet), 164ms response p95, x402 compliance 14 of 14, $0.002 price against the category. 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.

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.

It is a score inside Blockchain, 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 95 listings, this one among them: the same 95 the position above is counted against. When the two differ, the field is the wider one, 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.

All measured facts

What it does

Pay-per-call EVM transaction simulation and calldata decoder for AI agents: decode raw calldata into a named function with security risk flags, and run a keyless eth_call preview to see whether a transaction would succeed or revert before signing. Across Base, Ethereum, Arbitrum, Optimism, Polygon, BSC. No API keys, no node infra: one x402 USDC micropayment per call.

TxSim Decoder is a listed x402 Blockchain API. Captured payment terms name Base. Monitoring and settlement figures below describe the observations available to this directory; an unpaid HTTP 402 check does not prove that a paid call will deliver.

Assessment computed at . Latest service check observed at . Service data JSON · Measurement methodology.

Page rendered at . This response time is separate from the observation and computation times attached to each measurement.

Latest endpoint observation: . Latest price capture: . Prices are recorded quotes, not a promise of availability. Token assets and payment terms are listed separately. Endpoint data JSON · Price history JSON · Measurement methodology.

Assessment computed at . Uptime uses the stated daily-rollup window; response times are in milliseconds, compliance is passed/evaluated checks, and traction is a measured settlement floor. The comparison score is out of 100 within this category. Assessment JSON · Measurement methodology.

Observed daily coverage: 2026-10-10 to 2026-11-08 UTC. Daily monitoring and settlement rollups do not expose their computation time; a bucket date is not an update timestamp. Uptime and response JSON · Volume JSON · Buyers JSON · Measurement methodology.

Ranked from the measured category pool, refreshed at most once a minute. The comparison has no persisted computation timestamp; the assessment time above belongs to this service only. Ranking API documentation · Ranking methodology.

x402 List home · Services · Blockchain

uptime · latest daily rollup
-
uptime 7d
-
uptime 30d
-
uptime 90d
-
response p95
164ms
avg response
164ms
total checks
1

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

price (min)
$0.002
price (max)
$0.02
category percentile (min)
p27 in Blockchain
category percentile (max)
p54 in Blockchain
endpoints / prices
3 / 3
model
tiered
stability
100%

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
81d
registrar
HOSTINGER operations, UAB
hosting
custom
domain created
2026-08-17

Identity facts, not a risk score.

On-chain traction has not been assessed for this service yet.

member since
2026-11-07
Recent checks
Latest 12 unpaid HTTP checks, newest first; response times in milliseconds, observation times in UTC
Checked at (UTC)StatusHTTPResponseEndpoints
Online402149ms3
Online402367ms3
Online40282ms3
Online40284ms3
Online402162ms3
Online402111ms3
Online402105ms3
Online402271ms3
Online40273ms3
Online402143ms3
Online402106ms3
Online402164ms3

Changes0 in 30d

No changes recorded in the last 30 days.

all changes

Over time

On-chain volume

On-chain traction has not been assessed for this service yet.

Uptime 100% on all 1 completed day
Uptime
100% on all 1 completed day

On-chain traction has not been assessed for this service yet.

More charts
Response time daily average, ms min 110ms, avg 127ms, max 144ms

10-10 to 11-08* UTC

Each series spans only the dates it has data for. Every series is also served as JSON at /api/v1/services/txsim-decoder/price, /scores, /volume and /buyers.

Values

* today so far, partial (UTC).

The uptime summary counts completed UTC days only. The strip, readouts and table retain today's partial reading.

Assessment history last recorded at . Each UTC day uses its last recorded run; missing readings stay unmeasured. Assessment history JSON · Measurement methodology.

Daily values, 2026-11-07 to 2026-11-08: uptime percent, average response milliseconds, compliance passed/total, price percentile 0-100, site signals out of 6; UTC dates
DayUptimeResponseCompliancePrice percentileSite signals
2026-11-07100%143.67ms14/14p276/6
2026-11-08*100%109.75msno datano datano data

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5 of 94 other ranked services in Blockchain, ordered by the same measured score.

see the whole category

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Earn the verified tier: x402list pays a real call to this endpoint and, if it delivers, the service is delivery-verified. The fee covers the cost of the probe, not the badge; there is no refund if the call does not deliver. Agent and API only, no in-browser signing. See /api.

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