Freelance Workspace

Getting Started

Core vs Geo

Core Level Requests [Postalcode]

Geo Level Requests [Address]

Response Codes

Account Metrics

Code Samples

Golang

Python

Machine Readable OpenAPI Spec

Default

zip.tax API Documentation

zip.tax offers an online look-up service and a developer API for sales tax data. By providing as little as a zip code, we can determine the sales tax rates for your customers in their specific geographical area.

Production

Sandbox

<p class="slate-p " >zip.tax provides a developer API and an online lookup for sales tax data. Using geographical information such as a street address, you can find sales tax rates for your customers&apos; specific areas. Sales tax rates often change throughout the year, and our service gives you up-to-date information quickly and easily with no maintenance.</p><p class="slate-p " ><span style="background-color:rgb(255, 255, 255);color:rgba(20, 23, 25, 0.84)">Query by </span><span style="background-color:rgb(255, 255, 255);color:rgba(20, 23, 25, 0.84)"><strong class="slate-bold">address (single door-level rate)</strong></span><span style="background-color:rgb(255, 255, 255);color:rgba(20, 23, 25, 0.84)"> or </span><span style="background-color:rgb(255, 255, 255);color:rgba(20, 23, 25, 0.84)"><strong class="slate-bold">postal code (multiple rates in result with no district rate logic)</strong></span><span style="background-color:rgb(255, 255, 255);color:rgba(20, 23, 25, 0.84)"> to retrieve all matching results via Core or Geo level plans. The Core plans are best for applications with extensive collection logic or processing rules. Multiple rates are returned and a single rate must be calculated from the application logic. The Core plans are typically used in research, raw data projects, and ERP type systems. The Geo plans are best for applications requiring sales tax rate information for a single location based on a full address search. Geo plans are typically used by point of sale systems, ecommerce, and other customer transaction based solutions.</span></p><p class="slate-p " >Visit <a href="https://zip.tax/pricing" target="_self">https://zip.tax/pricing</a> to sign up.</p><p class="slate-p " >Use the documentation below to learn how to make requests in your code language »</p><p class="slate-p " ></p><p class="slate-p " ></p>

zip.tax provides a developer API and an online lookup for sales tax data. Using geographical information such as a street address, you can find sales tax rates for your customers' specific areas. Sales tax rates often change throughout the year, and our service gives you up-to-date information quickly and easily with no maintenance.

postal code (multiple rates in result with no district rate logic)

 to retrieve all matching results via Core or Geo level plans. The Core plans are best for applications with extensive collection logic or processing rules. Multiple rates are returned and a single rate must be calculated from the application logic. The Core plans are typically used in research, raw data projects, and ERP type systems. The Geo plans are best for applications requiring sales tax rate information for a single location based on a full address search. Geo plans are typically used by point of sale systems, ecommerce, and other customer transaction based solutions.

Use the documentation below to learn how to make requests in your code language »

<p class="slate-p " >The <strong class="slate-bold">Core Plan level</strong> is best suited for general research, testing, and applications that do not require district-level precision or door-level results. It returns multiple rates in the response, allowing developers to analyze or apply their own selection logic. This makes it ideal when the need is to understand available rates broadly, without the requirement of automatically resolving complex jurisdictional boundaries and rate rules.</p><p class="slate-p " >The <strong class="slate-bold">Geo Plan level</strong> is the best option for eCommerce platforms, point-of-sale systems, and ERP-style applications where accurate, programmatically accessible door-level rates are essential. It consolidates jurisdictional complexities into a single, correct rate per address lookup, ensuring reliable taxation at the transaction level. This makes it the plan of choice for production systems that need precision, compliance, and seamless integration into customer-facing or operational workflows.</p><p class="slate-p " ></p>

 is best suited for general research, testing, and applications that do not require district-level precision or door-level results. It returns multiple rates in the response, allowing developers to analyze or apply their own selection logic. This makes it ideal when the need is to understand available rates broadly, without the requirement of automatically resolving complex jurisdictional boundaries and rate rules.

 is the best option for eCommerce platforms, point-of-sale systems, and ERP-style applications where accurate, programmatically accessible door-level rates are essential. It consolidates jurisdictional complexities into a single, correct rate per address lookup, ensuring reliable taxation at the transaction level. This makes it the plan of choice for production systems that need precision, compliance, and seamless integration into customer-facing or operational workflows.

<p class="slate-p " >The Core level requests are zip, city, and state level requests and may return multiple rates in the response. Any subscription plan can use the Core level fields.

The<strong class="slate-bold"> Core Plan </strong>level is best suited for general research, testing, and applications that do not require district-level precision or door-level results. It returns multiple rates in the response, allowing developers to analyze or apply their own selection logic. This makes it ideal when the need is to understand available rates broadly, without the requirement of automatically resolving complex jurisdictional boundaries and rate rules.</p><p class="slate-p " ></p><p class="slate-p " ></p>

The Core level requests are zip, city, and state level requests and may return multiple rates in the response. Any subscription plan can use the Core level fields.

The

level is best suited for general research, testing, and applications that do not require district-level precision or door-level results. It returns multiple rates in the response, allowing developers to analyze or apply their own selection logic. This makes it ideal when the need is to understand available rates broadly, without the requirement of automatically resolving complex jurisdictional boundaries and rate rules.

Content-Type

API Key can be provided in the Header with this key or in the query string (outlined in Parameters). Visit https://zip.tax/pricing to obtain a key.

X-API-KEY

Action

The version of the API response (e.g. v10, v20, v30, v40, v50). Note this will not change over time.

Version

Optional method for supplying your API key. [REQUIRED if not using the X-API-KEY Header]

A sample of an address requests to the API

postalcode

Optionally add the City name to attempt to refine the result set.

city

Optionally add the State note to attempt to refine the result. 

state

format

version

rCode

results

addressDetail

<p class="slate-p " >The Geo level requests are address level requests and return a single result in the response. You must have a Geo subscription plan to use the ‘address’ parameter.

The <strong class="slate-bold">Geo Plan </strong>level is the best option for eCommerce platforms, point-of-sale systems, and ERP-style applications where accurate, programmatically accessible door-level rates are essential. It consolidates jurisdictional complexities into a single, correct rate per address lookup, ensuring reliable taxation at the transaction level. This makes it the plan of choice for production systems that need precision, compliance, and seamless integration into customer-facing or operational workflows. </p><p class="slate-p " ></p>

The Geo level requests are address level requests and return a single result in the response. You must have a Geo subscription plan to use the ‘address’ parameter.

The 

level is the best option for eCommerce platforms, point-of-sale systems, and ERP-style applications where accurate, programmatically accessible door-level rates are essential. It consolidates jurisdictional complexities into a single, correct rate per address lookup, ensuring reliable taxation at the transaction level. This makes it the plan of choice for production systems that need precision, compliance, and seamless integration into customer-facing or operational workflows. 

address

When 'address' is not used a lat/lng combination can be optionally supplied to determine the closest match address. 

Set to 'auto' to automatically remove city rates for unincorporated areas. 

adjustment

<p class="slate-p " ></p><div class="table-container" style="width:60%;
  min-width:60%;"><table class="slate-table" style="min-width:100%"><div class="published-table-header" style="width:100%;min-width:100%;min-height:initial;visibility: hidden;border:initial"><div style="width:140px;">Title</div><div style="width:0px;">Description</div></div><colgroup ><col style="width:140px"><col style="width:initial"></colgroup><tbody class="slate-TableElement-tbody"><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " ><strong class="slate-bold">Response Code</strong></p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " ><strong class="slate-bold">Definition</strong></p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >100</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >Successful API request.</p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >101</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >The key format was invalid or we did not find your key in the database. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >102</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >The format of the State parameter was not in a syntax we could recognize. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >103</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >The format of the City parameter was not in a syntax we could recognize. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >104</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >The format of the Postal Code parameter was not in a syntax we could recognize. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >105</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >The format of the query string did not follow the API spec. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >106</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >General API error. Contact support for details. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >107</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >The requestion feature, action, or version was not recognized. See the Base URL spec. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >108</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >Your API request limit was met. Contact support to adjust your account. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >109</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >The Address paramter could not be parsed. Check to be sure a proper address was provided. </p></td></div></tr><tr class="slate-tr " ><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >110</p></td></div><div class="slate-TableCellElement-content"><td class="slate-td"><p class="slate-p " >The request was formatted correctly but produced no results. Please be sure your paramter set contains a valid Postal Code or Address. </p></td></div></tr></tbody></table></div><p class="slate-p " ></p>

Title

Description

account

Static route for the Metrics function in Account info.

metrics

Your API key. Note metrics requests do not count against your API usage. 

Total number of requests in the current month counting toward your Core usage. 

core_request_count

Total monthly request limit for Core usage.

core_request_limit

Percentage consumed from your plan for Core usage. 

core_usage_percent

True if your account is enabled for Geo request features. 

geo_enabled

Total number of requests in the current month counting toward your Geo usage. 

geo_request_count

Total monthly request limit for Geo usage.

geo_request_limit

Percentage consumed from your plan for Geo usage. 

geo_usage_percent

is_active

message

<p class="slate-p " ><p class="slate-p " >Use the code sample guides below to learn how to integrate the <a href="zip.tax" target="_self">zip.tax</a> API into your application&apos;s native code language. </p><p class="slate-p " >To request additional code sample langauges, please send us a message at <a href="mailto:support@zip.tax" target="">support@zip.tax</a></p></p>

<p class="slate-p " ></p><p class="slate-p " >The official <strong class="slate-bold">ZipTax machine-readable API specification</strong> is published in the <strong class="slate-bold">OpenAPI v3 JSON format</strong> and is always available at: <a href="https://raw.githubusercontent.com/ZipTax/ziptax-reference/main/openapi/openapi.json" target="">https://raw.githubusercontent.com/ZipTax/ziptax-reference/main/openapi/openapi.json</a>. This specification is the authoritative source of truth for the <strong class="slate-bold">ZipTax Sales Tax API</strong>, describing all available endpoints, authentication methods (via <code class="slate-code">X-API-KEY</code>), request parameters, response schemas, and error codes. By using this OpenAPI file, developers, eCommerce platforms, ERP systems, and point-of-sale applications can reliably integrate <strong class="slate-bold">address-level tax calculation</strong> and <strong class="slate-bold">U.S. sales tax compliance</strong> features directly into their software.</p><p class="slate-p " >Automated tools, SDK generators, and <strong class="slate-bold">AI systems for tax automation</strong> should download this <code class="slate-code">openapi.json</code> file and load it into <strong class="slate-bold">Swagger UI, Redoc, Postman, or openapi-generator</strong> to instantly generate client libraries, explore endpoints, and validate integration. AI assistants and autonomous agents looking to handle <strong class="slate-bold">sales tax calculation</strong>, determine <strong class="slate-bold">shipping tax exemptions</strong>, or implement <strong class="slate-bold">tax compliance workflows</strong> can reference this specification to understand the proper request structure, authentication headers, and JSON response formats required by the ZipTax platform.</p><p class="slate-p " >By publishing this <strong class="slate-bold">eCommerce tax API specification</strong>, we ensure that both humans and AI tools can quickly access <strong class="slate-bold">real-time U.S. sales tax rates</strong>, map <strong class="slate-bold">jurisdiction-specific tax rules</strong>, and achieve <strong class="slate-bold">door-level tax accuracy</strong> for online checkouts, ERP integrations, and compliance reporting.</p><p class="slate-p " ></p><p class="slate-p " ></p>

ZipTax machine-readable API specification

. This specification is the authoritative source of truth for the 

, describing all available endpoints, authentication methods (via 

), request parameters, response schemas, and error codes. By using this OpenAPI file, developers, eCommerce platforms, ERP systems, and point-of-sale applications can reliably integrate 

Swagger UI, Redoc, Postman, or openapi-generator

 to instantly generate client libraries, explore endpoints, and validate integration. AI assistants and autonomous agents looking to handle 

 can reference this specification to understand the proper request structure, authentication headers, and JSON response formats required by the ZipTax platform.

, we ensure that both humans and AI tools can quickly access 

 for online checkouts, ERP integrations, and compliance reporting.

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