Freelance Workspace

Getting Started

Core vs Geo

Postal Code Level Requests (Core)

Address Level Requests (Geo)

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.<span style="background-color:#FFFFFF;color:#FE0000"> </span></p><div style="width:100%;
	min-width:100%;" class="callout-widget" data-type=info ><div class="callout-icon"><svg width="20" height="20" viewBox="0 0 20 20" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M10.0628 14.1676C10.2434 14.1676 10.3927 14.1086 10.5107 13.9905C10.6288 13.8725 10.6878 13.7232 10.6878 13.5426V9.77177C10.6878 9.6051 10.6253 9.46274 10.5003 9.34469C10.3753 9.22663 10.2295 9.1676 10.0628 9.1676C9.88227 9.1676 9.73296 9.22663 9.61491 9.34469C9.49685 9.46274 9.43783 9.61205 9.43783 9.7926V13.5634C9.43783 13.7301 9.50033 13.8725 9.62533 13.9905C9.75033 14.1086 9.89616 14.1676 10.0628 14.1676ZM10.0003 7.62594C10.1948 7.62594 10.358 7.56344 10.4899 7.43844C10.6219 7.31344 10.6878 7.15371 10.6878 6.95927C10.6878 6.76482 10.6219 6.59816 10.4899 6.45927C10.358 6.32038 10.1948 6.25094 10.0003 6.25094C9.80588 6.25094 9.64269 6.32038 9.51074 6.45927C9.3788 6.59816 9.31283 6.76482 9.31283 6.95927C9.31283 7.15371 9.3788 7.31344 9.51074 7.43844C9.64269 7.56344 9.80588 7.62594 10.0003 7.62594ZM10.0003 18.3343C8.81977 18.3343 7.72255 18.1225 6.70866 17.6989C5.69477 17.2752 4.81283 16.6884 4.06283 15.9384C3.31283 15.1884 2.72602 14.3065 2.30241 13.2926C1.8788 12.2787 1.66699 11.1815 1.66699 10.0009C1.66699 8.83427 1.8788 7.74399 2.30241 6.7301C2.72602 5.71621 3.31283 4.83427 4.06283 4.08427C4.81283 3.33427 5.69477 2.74399 6.70866 2.31344C7.72255 1.88288 8.81977 1.6676 10.0003 1.6676C11.167 1.6676 12.2573 1.88288 13.2712 2.31344C14.285 2.74399 15.167 3.33427 15.917 4.08427C16.667 4.83427 17.2573 5.71621 17.6878 6.7301C18.1184 7.74399 18.3337 8.83427 18.3337 10.0009C18.3337 11.1815 18.1184 12.2787 17.6878 13.2926C17.2573 14.3065 16.667 15.1884 15.917 15.9384C15.167 16.6884 14.285 17.2752 13.2712 17.6989C12.2573 18.1225 11.167 18.3343 10.0003 18.3343ZM10.0003 17.0843C11.9448 17.0843 13.6114 16.3898 15.0003 15.0009C16.3892 13.612 17.0837 11.9454 17.0837 10.0009C17.0837 8.05649 16.3892 6.38982 15.0003 5.00094C13.6114 3.61205 11.9448 2.9176 10.0003 2.9176C8.05588 2.9176 6.38921 3.61205 5.00033 5.00094C3.61144 6.38982 2.91699 8.05649 2.91699 10.0009C2.91699 11.9454 3.61144 13.612 5.00033 15.0009C6.38921 16.3898 8.05588 17.0843 10.0003 17.0843Z" fill="#3960B4"></path></svg></div><div ><p class="slate-p " ><span style="color:#FE0000">NOTE: Postal code level requests are not adjusted for unincorporated areas or local jurisdictions. See </span><a href="67083af8aefeaba8b26ce9bd" target=""><span style="color:#6C9EEB">Address Level Requests</span></a><span style="color:#FE0000"> to get local jurisdiction adjusted door-level-rates. </span></p></div></div><p class="slate-p " ></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><div style="width:100%;
	min-width:100%;" class="callout-widget" data-type=info ><div class="callout-icon"><svg width="20" height="20" viewBox="0 0 20 20" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M10.0628 14.1676C10.2434 14.1676 10.3927 14.1086 10.5107 13.9905C10.6288 13.8725 10.6878 13.7232 10.6878 13.5426V9.77177C10.6878 9.6051 10.6253 9.46274 10.5003 9.34469C10.3753 9.22663 10.2295 9.1676 10.0628 9.1676C9.88227 9.1676 9.73296 9.22663 9.61491 9.34469C9.49685 9.46274 9.43783 9.61205 9.43783 9.7926V13.5634C9.43783 13.7301 9.50033 13.8725 9.62533 13.9905C9.75033 14.1086 9.89616 14.1676 10.0628 14.1676ZM10.0003 7.62594C10.1948 7.62594 10.358 7.56344 10.4899 7.43844C10.6219 7.31344 10.6878 7.15371 10.6878 6.95927C10.6878 6.76482 10.6219 6.59816 10.4899 6.45927C10.358 6.32038 10.1948 6.25094 10.0003 6.25094C9.80588 6.25094 9.64269 6.32038 9.51074 6.45927C9.3788 6.59816 9.31283 6.76482 9.31283 6.95927C9.31283 7.15371 9.3788 7.31344 9.51074 7.43844C9.64269 7.56344 9.80588 7.62594 10.0003 7.62594ZM10.0003 18.3343C8.81977 18.3343 7.72255 18.1225 6.70866 17.6989C5.69477 17.2752 4.81283 16.6884 4.06283 15.9384C3.31283 15.1884 2.72602 14.3065 2.30241 13.2926C1.8788 12.2787 1.66699 11.1815 1.66699 10.0009C1.66699 8.83427 1.8788 7.74399 2.30241 6.7301C2.72602 5.71621 3.31283 4.83427 4.06283 4.08427C4.81283 3.33427 5.69477 2.74399 6.70866 2.31344C7.72255 1.88288 8.81977 1.6676 10.0003 1.6676C11.167 1.6676 12.2573 1.88288 13.2712 2.31344C14.285 2.74399 15.167 3.33427 15.917 4.08427C16.667 4.83427 17.2573 5.71621 17.6878 6.7301C18.1184 7.74399 18.3337 8.83427 18.3337 10.0009C18.3337 11.1815 18.1184 12.2787 17.6878 13.2926C17.2573 14.3065 16.667 15.1884 15.917 15.9384C15.167 16.6884 14.285 17.2752 13.2712 17.6989C12.2573 18.1225 11.167 18.3343 10.0003 18.3343ZM10.0003 17.0843C11.9448 17.0843 13.6114 16.3898 15.0003 15.0009C16.3892 13.612 17.0837 11.9454 17.0837 10.0009C17.0837 8.05649 16.3892 6.38982 15.0003 5.00094C13.6114 3.61205 11.9448 2.9176 10.0003 2.9176C8.05588 2.9176 6.38921 3.61205 5.00033 5.00094C3.61144 6.38982 2.91699 8.05649 2.91699 10.0009C2.91699 11.9454 3.61144 13.612 5.00033 15.0009C6.38921 16.3898 8.05588 17.0843 10.0003 17.0843Z" fill="#3960B4"></path></svg></div><div ><p class="slate-p " ><span style="color:#FE0000">NOTE: Use </span><span style="color:#4C1130"><code class="slate-code">adjustment=auto</code></span><span style="color:#FE0000"> to automatically adjust for local jurisdiction tax rates (i.e. unincorporarted areas and special taxing jurisdictions). </span></p></div></div><p class="slate-p " ></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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