Invoice Arithmetic Audit
Recompute an invoice exactly and report where it disagrees with itself. Quantity times unit price is an exact decimal product. Rounding happens only where the stated policy says: per line, or once on the whole invoice. Those give different totals, so the difference between the two policies is published rather than one being assumed correct. Also reports a figure with more decimal places than its currency has, and a discount larger than its line.
Searchofflineeip155:8453Exactvia cdp
InvoicingExact arithmeticBillingRounding policyDeveloper tooling
Settlements · 30d
218↓ 56%
No per-endpoint history for this service yet, so this is payments indexed to its PROVIDER's wallet over 30 days.
$25.30
Verified settled volume
255 settlements proven x402 by their on-chain EIP-3009 marker.
$0.220
Listed price
As published in the catalog. Always read the live 402 before paying.
1
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-10-04 08:36Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x25e8245f07d5e4873987293dad666afbe56a9608The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Provider
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
0.22USDC≈ $0.22 USD
on Base · exact scheme
Pay 0.22 USDC on Base to 0x25e8…a9608. The signed payment is good for 1 minute.
- Paid to
- 0x25e8…a9608
- USD Coin contract
- 0x8335…02913
- Payment window
- 1 minute
- As published
- 220000 smallest units
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x25e8245f07d5e4873987293dad666afbe56a9608",
"amount": "220000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 60
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"body": {
"policy": {
"rounding": "half_up",
"tax_inclusive": false,
"round_per_line": true
},
"invoice": {
"id": "INV-7781",
"lines": [
{
"quantity": "3",
"tax_rate": "10",
"line_total": "59.97",
"tax_amount": "6.00",
"unit_price": "19.99",
"description": "Widget"
},
{
"quantity": "7",
"tax_rate": "10",
"line_total": "7.03",
"tax_amount": "0.70",
"unit_price": "1.005",
"description": "Washer"
},
{
"discount": "120.00",
"quantity": "1",
"tax_rate": "10",
"line_total": "-20.00",
"tax_amount": "-1.82",
"unit_price": "100.00",
"description": "Service call"
}
],
"total": "51.88",
"currency": "AUD",
"subtotal": "47.00",
"tax_total": "4.88"
}
},
"type": "http",
"method": "POST",
"bodyType": "json"
},
"output": {
"type": "json",
"example": {
"lines": [
{
"line": 1,
"discount": "0",
"quantity": "3",
"tax_rate": "10",
"net_exact": "59.97",
"tax_exact": "5.997",
"unit_price": "19.99",
"net_rounded": "59.97",
"tax_rounded": "6"
},
{
"line": 2,
"discount": "0",
"quantity": "7",
"tax_rate": "10",
"net_exact": "7.035",
"tax_exact": "0.704",
"unit_price": "1.005",
"net_rounded": "7.04",
"tax_rounded": "0.7"
},
{
"line": 3,
"discount": "120",
"quantity": "1",
"tax_rate": "10",
"net_exact": "-20",
"tax_exact": "-2",
"unit_price": "100",
"net_rounded": "-20",
"tax_rounded": "-2"
}
],
"limits": {
"maxEntries": 20000,
"maxAccounts": 5000,
"maxFindings": 500,
"maxLinesPerEntry": 500,
"maxStatementLines": 20000
},
"passed": false,
"complete": true,
"currency": "AUD",
"findings": [
{
"code": "LINE_TOTAL_DISAGREES",
"line": 2,
"detail": "line 2 declares 7.03 and 7 at 1.005 gives 7.04 under half_up rounding to 2 place(s), out by exactly -0.01."
},
{
"code": "DISCOUNT_EXCEEDS_LINE",
"line": 3,
"detail": "line 3 discounts 120 against a line of 100, so the line is negative by exactly 20."
},
{
"code": "LINE_TAX_DISAGREES",
"line": 3,
"detail": "line 3 declares tax of -1.82 and 10% on -20 gives -2, out by exactly 0.18."
}
],
"invoice_id": "INV-7781",
"line_count": 3,
"request_id": "example-request",
"service_id": "invoice_arithmetic_audit",
"assumptions": [
"Quantity times unit price is an exact decimal product, which never loses a digit. Rounding happens only where the policy says it happens, and the policy is stated by the caller rather than assumed.",
"Rounding per line and rounding the whole invoice give different totals. Both are defensible, so the difference between them is computed and published rather than one being treated as correct.",
"Tax-inclusive and tax-exclusive are different formulas that do not round to the same figure, which is why an invoice built one way and checked the other is always out by a cent. The policy says which ..."
],
"limitations": [
"Whether the arithmetic on the invoice supplied is self-consistent under the policy supplied. Not tax advice and not accounting advice: whether a rate is the right rate, whether a supply is taxable, an...",
"arithmetic_sound is true only when every declared figure matched the computed one and every figure fitted the currency."
],
"minor_units": 2,
"observed_at": "2026-10-02T00:00:00.000Z",
"not_examined": [],
"finding_count": 6,
"rounding_mode": "half_up",
"tax_inclusive": false,
"computed_total": "51.71",
"service_version": "1.0.0",
"arithmetic_sound": false,
"findings_by_code": {
"TOTAL_DISAGREES": 1,
"LINE_TAX_DISAGREES": 1,
"SUBTOTAL_DISAGREES": 1,
"TAX_TOTAL_DISAGREES": 1,
"LINE_TOTAL_DISAGREES": 1,
"DISCOUNT_EXCEEDS_LINE": 1
},
"rounded_per_line": true,
"computed_subtotal": "47.01",
"computed_tax_total": "4.7",
"subtotal_exact_unrounded": "47.005",
"rounding_policy_difference": "0"
}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"bodyType",
"body"
],
"properties": {
"body": {
"type": "object",
"required": [
"invoice"
],
"properties": {
"policy": {
"type": "object",
"properties": {
"rounding": {
"enum": [
"half_up",
"half_even",
"down",
"up"
],
"type": "string"
},
"minor_units": {
"type": "object"
},
"tax_inclusive": {
"type": "boolean"
},
"round_per_line": {
"type": "boolean"
}
},
"additionalProperties": false
},
"invoice": {
"type": "object",
"required": [
"currency",
"lines"
],
"properties": {
"id": {
"type": "string",
"maxLength": 128
},
"lines": {
"type": "array",
"items": {
"type": "object",
"required": [
"quantity",
"unit_price"
],
"properties": {
"discount": {
"type": [
"string",
"number"
]
},
"quantity": {
"type": [
"string",
"number"
]
},
"tax_rate": {
"type": [
"string",
"number"
]
},
"line_total": {
"type": [
"string",
"number"
]
},
"tax_amount": {
"type": [
"string",
"number"
]
},
"unit_price": {
"type": [
"string",
"number"
]
},
"description": {
"type": "string",
"maxLength": 512
}
},
"additionalProperties": false
},
"maxItems": 500,
"minItems": 1
},
"total": {
"type": [
"string",
"number"
]
},
"currency": {
"type": "string",
"maxLength": 8
},
"subtotal": {
"type": [
"string",
"number"
]
},
"tax_total": {
"type": [
"string",
"number"
]
}
},
"additionalProperties": false
}
},
"additionalProperties": false
},
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
}
}
}Provenance
- Seen in the source catalog
- 2026-10-04 08:37Z
- Last indexed by Roundhouse
- 2026-10-05 00:20Z
- Last enriched (probe, favicon, geo)
- 2026-10-05 00:45Z
- x402 version
- 2
- Max timeout
- 60s
- Liveness probe
- HTTP 0
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
No per-endpoint history for this service yet, so this is payments indexed to its PROVIDER's wallet over 30 days. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service Invoice Arithmetic Audit and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Invoice%20Arithmetic%20Audit' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://api.zfinia.com/x402/v1/invoice-arithmetic-audit, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.