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AgentTax

payment-readyonline

payment-ready until 2026-10-23

US sales tax calculation API for AI-agent commerce.

Call it x402 v2

x402 v2

Base URL
https://www.agenttax.io
Payment
x402 v2, header channel
$ curl -i 'https://www.agenttax.io/api/v1/calculate'

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

Endpoints 1 paid route on www.agenttax.io

GET/api/v1/calculateBase$0.005since 08-31

Prices as captured in the 402 response: $0.005.

Example 402 response

Endpoints and prices

Current paid endpoints; minimum quoted prices in USD where available; first capture dates in UTC
MethodPathDescriptionPriceNetworkAsset402 channelCaptured
GET/api/v1/calculateAgentTax · AI agent tax calculation across 51 US jurisdictions including 304 local zip-level rates. Sales tax, use tax, nexus monitoring, 1099-DA export.$0.005BaseUSDCheadersince 08-31

Payment evidence

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

1 payload captured by the monitor for GET /api/v1/calculate.

415 lines, scroll inside

{
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x6f4B383B3DB9115120638DceF88F2fd382ADd6F7",
      "amount": "5000",
      "scheme": "exact",
      "network": "base",
      "mimeType": "application/json",
      "resource": "https://www.agenttax.io/api/v1/calculate",
      "description": "AgentTax — Sales tax calculation for AI agent transactions across 51 US jurisdictions (50 states + DC) including 304 zip-level local rates. Returns sales tax, use tax, nexus status, confidence score, and citation sources. Purpose-built for x402-native agent-to-agent commerce, MCP tool monetization, and AI agent compliance. Free tier 100 calls/mo.",
      "facilitator": "https://api.cdp.coinbase.com/platform/v2/x402",
      "outputSchema": {
        "input": {
          "type": "http",
          "method": "POST",
          "bodyFields": {
            "role": {
              "enum": [
                "seller",
                "buyer"
              ],
              "type": "string",
              "required": true,
              "description": "Your role in the transaction"
            },
            "amount": {
              "type": "number",
              "required": true,
              "description": "Transaction amount in USD (0–100M)"
            },
            "is_b2b": {
              "type": "boolean",
              "description": "Business-to-business (affects IA, MD, NJ exemptions)"
            },
            "buyer_zip": {
              "type": "string",
              "description": "Optional 5-digit zip for local rate lookup"
            },
            "work_type": {
              "enum": [
                "compute",
                "research",
                "content",
                "consulting",
                "trading"
              ],
              "type": "string",
              "description": "Economic category of work — improves accuracy for TX, NY, NJ, MD, PA, CT, WA, IA"
            },
            "buyer_state": {
              "type": "string",
              "required": true,
              "description": "US state code (2-letter, e.g. TX, NY, CA)"
            },
            "counterparty_id": {
              "type": "string",
              "required": true,
              "description": "Identifier for the other party"
            },
            "transaction_type": {
              "enum": [
                "compute",
                "api_access",
                "data_purchase",
                "saas",
                "ai_labor",
                "storage",
                "digital_good",
                "consulting",
                "data_processing",
                "cloud_infrastructure",
                "ai_model_access",
                "marketplace_fee",
                "subscription",
                "license",
                "service"
              ],
              "type": "string",
              "required": true,
              "description": "Type of AI/digital transaction"
            }
          },
          "discoverable": true
        },
        "output": {
          "response": {
            "type": "object",
            "required": true,
            "description": "Sales tax, use tax, nexus status, confidence score, and citation sources for an AI agent transaction across 51 US jurisdictions. Includes engine_version on every response."
          }
        }
      },
      "maxAmountRequired": "5000",
      "maxTimeoutSeconds": 300
    },
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x6f4B383B3DB9115120638DceF88F2fd382ADd6F7",
      "amount": "5000",
      "scheme": "exact",
      "network": "base",
      "mimeType": "application/json",
      "resource": "https://www.agenttax.io/api/v1/calculate",
      "description": "AgentTax — Sales tax calculation for AI agent transactions across 51 US jurisdictions (50 states + DC) including 304 zip-level local rates. Returns sales tax, use tax, nexus status, confidence score, and citation sources. Purpose-built for x402-native agent-to-agent commerce, MCP tool monetization, and AI agent compliance. Free tier 100 calls/mo.",
      "facilitator": "https://x402.org/facilitator",
      "outputSchema": {
        "input": {
          "type": "http",
          "method": "POST",
          "bodyFields": {
            "role": {
              "enum": [
                "seller",
                "buyer"
              ],
              "type": "string",
              "required": true,
              "description": "Your role in the transaction"
            },
            "amount": {
              "type": "number",
              "required": true,
              "description": "Transaction amount in USD (0–100M)"
            },
            "is_b2b": {
              "type": "boolean",
              "description": "Business-to-business (affects IA, MD, NJ exemptions)"
            },
            "buyer_zip": {
              "type": "string",
              "description": "Optional 5-digit zip for local rate lookup"
            },
            "work_type": {
              "enum": [
                "compute",
                "research",
                "content",
                "consulting",
                "trading"
              ],
              "type": "string",
              "description": "Economic category of work — improves accuracy for TX, NY, NJ, MD, PA, CT, WA, IA"
            },
            "buyer_state": {
              "type": "string",
              "required": true,
              "description": "US state code (2-letter, e.g. TX, NY, CA)"
            },
            "counterparty_id": {
              "type": "string",
              "required": true,
              "description": "Identifier for the other party"
            },
            "transaction_type": {
              "enum": [
                "compute",
                "api_access",
                "data_purchase",
                "saas",
                "ai_labor",
                "storage",
                "digital_good",
                "consulting",
                "data_processing",
                "cloud_infrastructure",
                "ai_model_access",
                "marketplace_fee",
                "subscription",
                "license",
                "service"
              ],
              "type": "string",
              "required": true,
              "description": "Type of AI/digital transaction"
            }
          },
          "discoverable": true
        },
        "output": {
          "response": {
            "type": "object",
            "required": true,
            "description": "Sales tax, use tax, nexus status, confidence score, and citation sources for an AI agent transaction across 51 US jurisdictions. Includes engine_version on every response."
          }
        }
      },
      "maxAmountRequired": "5000",
      "maxTimeoutSeconds": 300
    }
  ],
  "resource": {
    "url": "/api/v1/calculate",
    "method": "POST",
    "mimeType": "application/json",
    "description": "AgentTax — AI agent tax calculation across 51 US jurisdictions including 304 local zip-level rates. Sales tax, use tax, nexus monitoring, 1099-DA export."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "body": {
            "role": "seller",
            "amount": 5000,
            "is_b2b": false,
            "work_type": "compute",
            "buyer_state": "TX",
            "counterparty_id": "agent_buyer_42",
            "transaction_type": "compute"
          },
          "type": "http",
          "method": "POST",
          "schema": {
            "type": "object",
            "required": [
              "role",
              "amount",
              "buyer_state",
              "transaction_type",
              "counterparty_id"
            ],
            "properties": {
              "role": {
                "enum": [
                  "seller",
                  "buyer"
                ],
                "type": "string",
                "description": "Your role in the transaction"
              },
              "amount": {
                "type": "number",
                "maximum": 100000000,
                "minimum": 0,
                "description": "Transaction amount in USD (0–100M)"
              },
              "is_b2b": {
                "type": "boolean",
                "default": false,
                "description": "Business-to-business transaction (affects IA, MD, NJ exemptions)"
              },
              "buyer_zip": {
                "type": "string",
                "pattern": "^[0-9]{5}$",
                "description": "Optional 5-digit zip for local rate lookup"
              },
              "work_type": {
                "enum": [
                  "compute",
                  "research",
                  "content",
                  "consulting",
                  "trading"
                ],
                "type": "string",
                "description": "Economic category of work — improves accuracy for states with per-category rules (TX, NY, NJ, MD, PA, CT, WA, IA)"
              },
              "buyer_state": {
                "type": "string",
                "pattern": "^[A-Z]{2}$",
                "description": "US state code (2-letter, e.g. TX, NY, CA)"
              },
              "counterparty_id": {
                "type": "string",
                "description": "Identifier for the other party (e.g. agent_buyer_42)"
              },
              "transaction_type": {
                "enum": [
                  "compute",
                  "api_access",
                  "data_purchase",
                  "saas",
                  "ai_labor",
                  "storage",
                  "digital_good",
                  "consulting",
                  "data_processing",
                  "cloud_infrastructure",
                  "ai_model_access",
                  "marketplace_fee",
                  "subscription",
                  "license",
                  "service"
                ],
                "type": "string",
                "description": "Type of AI/digital transaction"
              }
            }
          },
          "contentType": "application/json"
        },
        "output": {
          "type": "json",
          "schema": {
            "type": "object",
            "properties": {
              "sources": {
                "type": "array",
                "items": {
                  "type": "object",
                  "properties": {
                    "url": {
                      "type": "string"
                    },
                    "citation": {
                      "type": "string"
                    }
                  }
                }
              },
              "success": {
                "type": "boolean"
              },
              "sales_tax": {
                "type": "object",
                "properties": {
                  "note": {
                    "type": "string"
                  },
                  "rate": {
                    "type": "number"
                  },
                  "amount": {
                    "type": "number"
                  },
                  "jurisdiction": {
                    "type": "string"
                  }
                }
              },
              "total_tax": {
                "type": "number",
                "description": "Total tax amount in USD"
              },
              "confidence": {
                "type": "object",
                "properties": {
                  "level": {
                    "enum": [
                      "low",
                      "medium",
                      "high"
                    ],
                    "type": "string"
                  },
                  "score": {
                    "type": "number",
                    "maximum": 100,
                    "minimum": 0
                  }
                }
              },
              "engine_version": {
                "type": "string"
              }
            }
          },
          "example": {
            "role": "seller",
            "amount": 5000,
            "sources": [
              {
                "url": "https://statutes.capitol.texas.gov/",
                "citation": "TX Tax Code §151.351"
              }
            ],
            "success": true,
            "sales_tax": {
              "note": "80% taxable (§151.351 statutory exemption)",
              "rate": 0.05,
              "type": "sales",
              "amount": 250,
              "jurisdiction": "Texas"
            },
            "total_tax": 250,
            "confidence": {
              "level": "high",
              "score": 85
            },
            "buyer_state": "TX",
            "engine_version": "1.5",
            "transaction_type": "compute",
            "classification_basis": "data_processing"
          }
        }
      },
      "name": "agenttax_calculate",
      "tags": [
        "tax",
        "sales-tax",
        "use-tax",
        "compliance",
        "nexus",
        "ai-agents",
        "agent-commerce",
        "x402",
        "mcp",
        "1099-da",
        "machine-to-machine",
        "capital-gains"
      ],
      "category": "finance",
      "description": "Sales tax calculation for AI agent transactions across 51 US jurisdictions (50 states + DC) including 304 zip-level local rates. Takes transaction amount, buyer state/zip, transaction type, and counterparty. Returns sales tax, use tax, nexus status, confidence score, and citation sources. Conservative-bias default. Supports TX 80% rule (§151.351), MD B2B/B2C split, NJ digital service treatment (TAM 2013-10), IA B2B exemption, CT data-processing rate distinction. Engine version tracked on every response. Purpose-built for x402-native agent-to-agent commerce, MCP tool monetization, and AI agent compliance. Free tier 100 calls/mo; paid tiers 10K-1M+ calls/mo."
    }
  },
  "x402Version": 2
}

Can I trust it score from our own monitoring

score from our own monitoring

81/100 Solid

#68 of 109 in Finance. Bands: strong 93+, solid 75+, mixed 55+, weak below 55.

Reliability
100% uptime 30d
Compliance
A 14/14 checks pass
Price
$0.005 p31 in Finance
Risk
clean no risk flag
Traction
$0.02 30d 1 buyers, top buyer 100% (address, not entity)
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 2026-08-31. Last up 2026-10-16.

── 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 30d, 1971ms response p95, x402 compliance 14 of 14, $0.005 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.

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 Finance, 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 109 listings, this one among them: the same 109 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.

Settled via coinbase ($0.01, 3 tx). Traction is a conservative undercount; first settlement seen 2026-04-15.

All measured facts

What it does

US sales tax calculation API for AI-agent commerce. Returns the combined state+local rate, taxability by work type, economic-nexus alerts and a confidence score for all 50 states + DC. Pay per call in USDC on Base via x402 ($0.005) or use an API key.

AgentTax is a listed x402 Finance 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: 2026-09-17 to 2026-10-16 UTC. Daily monitoring and settlement rollups do not expose their computation time; a bucket date is not an update timestamp. Latest settlement in the assessment: . 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 · Finance

uptime · latest daily rollup
100%
uptime 7d
100%
uptime 30d
100%
uptime 90d
100%
response p95
1971ms
avg response
935ms
total checks
2,707

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

price (min)
$0.005
category percentile (min)
p31 in Finance
endpoints / prices
1 / 1
model
flat
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
-
registrar
-
hosting
custom
domain created
---

Identity facts, not a risk score.

assessment volume 30d
$0.02
exact assessment volume 30d (USD)
0.015
assessment recorded at (UTC)
2026-10-16T05:13:06.045Z
buyers 30d
1
settlements 30d
3
measured since
2026-04-15 (start of our harvest window)
last settlement
2026-09-19
top buyer share
100% of 30d volume (address, not entity)
top 3 buyers share
100% of 30d volume (addresses, not entities)
concentrated volume
no
trend 7d vs 30d
0.00x the 30d daily rate
networks
eip155:8453
volume all-time
$0.02
settlements all-time
9
median settlement 30d
$0.005
max settlement 30d
$0.005

Assessment volume uses the latest 30d assessment. Over time sums daily address snapshots, rounded to cents and refreshed separately. The two sources can differ in timing, precision and shared-address attribution. Amounts use cents for comparison; known sub-cent values keep up to 12 significant digits. The exact stored assessment value is shown above.

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

Top buyer share lowers the on-chain traction part of the ranking score behind this page's verdict and /best, by up to half when one address holds all 30d volume. The Recommended and Highest volume sorts of the services list do not use it; they use the Concentrated volume rule instead.

member since
2026-08-31
Recent checks
Latest 18 unpaid HTTP checks, newest first; response times in milliseconds, observation times in UTC
Checked at (UTC)StatusHTTPResponseEndpoints
Online402804ms1
Online4021535ms1
Online4022038ms1
Online4021784ms1
Online402783ms1
Online402577ms1
Online402698ms1
Online402887ms1
Online4021221ms1
Online402715ms1
Online402565ms1
Online402524ms1
Online402393ms1
Online4021172ms1
Online402725ms1
Online402862ms1
Online402751ms1
Online402780ms1

Changes0 in 30d

No changes recorded in the last 30 days.

all changes

Over time

On-chain volume daily snapshots, USD 30d: $0.02, peak $0.01 on 09-18
volume no data in the payload
Distinct buyers per dayDistinct buyers per day
Uptime 100% on all 29 completed days
Volume 30d
$0.02
Uptime
100% on all 29 completed days
Daily on-chain settlement volume in US dollars, 2026-09-17 to 2026-10-16; highest day $0.01 on 09-18; 28 days have no data in the payload; distinct buyers per day
More charts
Response time daily average, ms min 354ms, avg 930ms, max 1675ms

09-17 to 10-16* UTC

Scores over time

x402 compliance low 14/14, high 14/14

09-17 to 10-16* UTC

Price percentile in Finance own low to high; exact values below

09-17 to 10-16* UTC

Site signals present (of 6) own low to high; exact values below

09-17 to 10-16* UTC

Scores: one day per column, 09-17 to 10-16*, on the columns of Response time. Uptime held 100% every day in this window, including any partial day. Daily readings remain in the Uptime strip and Values. The checklist grew from 11 to 14 checks on 2026-07-28, before this window. Pillar lines use their own low and high. Exact dated readings are available in each readout and in Values.

Each series spans only the dates it has data for. Every series is also served as JSON at /api/v1/services/agenttax/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.

Daily snapshot total, 30d: $0.02, peak $0.01 on 09-18. The visible 30d total in Traction comes from the latest assessment. These sources can differ in their window, refresh time, cent rounding and shared-address attribution.

Daily address snapshots: 2026-09-17 to 2026-10-16 UTC; * today so far, partial (UTC). Daily snapshots store cents. A recorded $0.00 with settlements cannot distinguish exact zero from volume rounded away. Lost precision is unavailable here.

Settlement volume uses the stored USD valuation of tracked payments; it is distinct from token quantities. USD-pegged assets are valued at 1 USD per token in these rollups. The measured settlement floor does not cover all payments to this service.

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

Daily values, 2026-09-17 to 2026-10-16: address settlement volume in USD, distinct buyer and settlement counts, uptime percent, average response milliseconds, compliance passed/total, price percentile 0-100, site signals out of 6; UTC dates
DayVolumeBuyersSettlementsUptimeResponseCompliancePrice percentileSite signals
2026-09-17no datano datano data100%871.36ms14/14p316/6
2026-09-18$0.0112100%935.62ms14/14p316/6
2026-09-19$0.0111100%840.06ms14/14p316/6
2026-09-20no datano datano data100%354.33ms14/14p316/6
2026-09-21no datano datano data100%532.34ms14/14p296/6
2026-09-22no datano datano data100%705.17ms14/14p296/6
2026-09-23no datano datano data100%664.43ms14/14p296/6
2026-09-24no datano datano data100%522.76ms14/14p296/6
2026-09-25no datano datano data100%542.10ms14/14p296/6
2026-09-26no datano datano data100%597.99ms14/14p296/6
2026-09-27no datano datano data100%763.96ms14/14p296/6
2026-09-28no datano datano data100%1283.20ms14/14p296/6
2026-09-29no datano datano data100%1406.61ms14/14p296/6
2026-09-30no datano datano data100%1348.11ms14/14p296/6
2026-10-01no datano datano data100%1157.02ms14/14p296/6
2026-10-02no datano datano data100%1333.43ms14/14p296/6
2026-10-03no datano datano data100%1208.08ms14/14p296/6
2026-10-04no datano datano data100%1017.40ms14/14p296/6
2026-10-05no datano datano data100%957.24ms14/14p296/6
2026-10-06no datano datano data100%986.54ms14/14p306/6
2026-10-07no datano datano data100%818.81ms14/14p306/6
2026-10-08no datano datano data100%850.44ms14/14p316/6
2026-10-09no datano datano data100%464.44ms14/14p316/6
2026-10-10no datano datano data100%1028.27ms14/14p316/6
2026-10-11no datano datano data100%1675.23ms14/14p316/6
2026-10-12no datano datano data100%1171.09ms14/14p316/6
2026-10-13no datano datano data100%911.97ms14/14p316/6
2026-10-14no datano datano data100%1061.10ms14/14p316/6
2026-10-15no datano datano data100%965.96ms14/14p316/6
2026-10-16*no datano datano data100%917.97ms14/14p316/6

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5 of 108 other ranked services in Finance, ordered by the same measured score.

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  <img src="https://x402-list.com/badge/agenttax.svg" alt="AgentTax listed on x402-list" height="28">
</a>

Markdown

[![AgentTax on x402-list](https://x402-list.com/badge/agenttax.svg)](https://x402-list.com/services/agenttax?utm_source=badge&utm_medium=referral&utm_campaign=embed)

HTML, live uptime variant

<a href="https://x402-list.com/services/agenttax?utm_source=badge&utm_medium=referral&utm_campaign=embed">
  <img src="https://x402-list.com/badge/agenttax.svg?data=uptime" alt="AgentTax uptime on x402-list" height="28">
</a>
Delisting

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