API version

Addresses

Preview addresses eligible for batch approval Batch-approve addresses Suggest a fill for one blank address Assign the business address to blank transactions Fill the organization's blank-address transactions Count addresses needing attention Re-queue invalid-address transactions for validation Suggest addresses for a partial input Suggest addresses for many inputs Summarize addresses by verification status Update transaction addresses in a batch Validate and enrich an address

API Keys

List API keys Create an API key Update an API key Revoke an API key

Attachments

List attachments for a related entity Upload an attachment Get an attachment by id Download an attachment

Billing

Get the organization's chargebee subscription Update the organization's billing contact email Get the organization's billing history chart Start a hosted chargebee checkout Get the organization's billing-lock detail Get the current month's billing estimate List the organization's invoices Download one invoice as a PDF Get usage detail for one invoice Update the organization's subscription plan Create a chargebee self-serve customer portal session Get unbilled usage since the last invoice

Certificate Imports

List certificate imports by review status Approve multiple certificate imports Confirm a bulk certificate upload List certificate imports by upload session Initiate a bulk certificate upload Approve a certificate import Get a certificate import's file URL Reject a certificate import

Compliance Documents

List compliance document catalog Replace one file under a many-file compliance document type Preview a compliance document file Add a file to a many-file compliance document type Add or replace a one-file compliance document

Connections

List connections Start an acumatica oauth connect Start an airwallex oauth connect Activate an apideck-backed connection Open an apideck vault session to edit a connection Connect an apideck-backed service Connect a bill.com account Validate bill.com credentials Enable tax collection on a bill.com connection Connect a bunny account Refresh a bunny connection's access token Connect a campfire account Validate campfire credentials Update a campfire connection's webhook signing secret Connect a chargebee account Connect a checkoutchamp account Summarize collected-tax tracking across your connections Start an ebay oauth connect Get ebay runame portal urls Start a freshbooks oauth connect List freshbooks businesses awaiting selection Finish connecting a freshbooks business Enable tax collection on a freshbooks connection Connect a hyperline account Validate hyperline credentials Connect a kill bill account Validate kill bill credentials Update a kill bill connection's HMAC secret Connect a maxio account Poll an oauth connection-creation status Connect an odoo account Validate odoo credentials Update an odoo connection's HMAC secret Connect a kong konnect metering & billing organization Validate a konnect personal access token Read openmeter connection fields for re-auth Connect an orb account Connect an ordway account Generate an ordway webhook secret Connect a plentyone account Validate plentyone credentials Disconnect a quickbooks connection Connect a recurly account Validate recurly credentials Connect a rillet account Update a rillet connection's webhook signing token Connect a shopify account manually Complete a shopify oauth connection Start a SHOPLINE oauth connect Connect a stripe account through the stripe app Connect a stripe account Connect a vertex o-series account Get a vertex o-series connection's install credentials Mark a vertex o-series connection as installed Connect a zenskar account Connect a zuora account Validate zuora credentials Save zuora L2 tax setup Get a connection by id Delete a connection Activate a connection Record a connection's native-tax-disabled attestation Confirm collected-tax mode for registrations on a connection Deactivate a connection Disable tax collection on a connection Enable tax collection on a connection Get a connection's L2 enablement readiness List a connection's unconfirmed collecting registrations Update a connection's settings Resync a connection Archive an archived connection's transactions Get a connection's collected-tax comparison

Credits

List credits Create a credit

Customers

List customers Create a customer Get a customer by id Update a customer Archive a customer Upsert a customer tax registration by tax id

Exemption Requests

List exemption requests Create an exemption request Get pre-send exemption-request conflicts for a customer List an exemption request's certificates Mark an exemption request completed Resend an exemption request's upload link Send an exemption-request reminder

Exemption Requests (Public)

Get the status of a public exemption request Confirm uploaded certificates for an exemption request Request presigned upload urls for an exemption request

Exemptions

List exemptions Create an exemption Create many exemptions List customers missing certificates Send missing-certificate requests Missing-certificate metrics Upload a certificate for a customer Poll a customer's certificate upload status Get an exemption by id Update an exemption Archive an exemption Upload an exemption certificate Download an exemption certificate

Experience

Dashboard task counts Onboarding step completion status

Filings

List filings Request back-filings List back-filing request options Get the current back-filing terms Approve filings in bulk Pause filings in bulk List filing jurisdictions Summarize filings Get a filing by id Approve a filing List a filing's deferred transactions Pause a filing

Imports

List imports Create an import and get a single-file upload URL Download a CSV import template Create upload targets for one or more CSV files Validate a CSV file Get an import by id Get a download link for an import's error artifact Import the validated rows Start processing an uploaded import

Marketplaces

List marketplaces Get a marketplace by id Update a marketplace's confirmation status List transactions matched to a marketplace Mark every matched transaction as a marketplace sale

Missing Certificates (Public)

Get the status of a public missing-certificate request Confirm uploaded certificates for a missing-certificate request Request presigned upload urls for a missing-certificate request

Nexus

List nexus determinations Export nexus report Get a nexus determination Disregard a nexus List a nexus's exposure history Resolve a nexus's collected-tax exposure

Organization Settings

Get organization settings Update organization settings Get exemption-reminder settings Update exemption-reminder settings

Organizations

Get organization details Update organization details List organizations Create an organization Summarize your organizations Get an organization by id Update an organization Archive an organization

Physical nexus

List physical presences Record a physical presence List the physical presence category catalog Get a physical presence Update a physical presence Delete a physical presence

Products

List products Create a product Approve partially-approved products in bulk Approve partially-approved products by category Get the resolved organization's in-progress bulk-classification import Cancel a bulk-classification import Confirm a bulk-classification import Get a bulk-classification import's before/after preview Get a bulk-classification import's rejected-rows file Get a bulk-classification import's review state Queue products for reclassification List the product category catalog Categorize and approve products Summarize product classification progress Check whether bulk classification can run List product configurations Create a product configuration List blocklisted product codes Add a product code to the blocklist Remove a product code from the blocklist Create product configurations in bulk Get a product configuration by id Update a product configuration Delete a product configuration Break down products by category Recategorize products in bulk Export products Summarize products by status Get a product by id Update a product Archive a product

Registrations

Get a jurisdiction's registration form List registration jurisdictions Preview registering a jurisdiction List registrations Create a registration Summarize registrations by status Get a registration by id Update a registration Upload an attachment for a registration Set a registration's credentials Reveal a registration's credentials Deregister a registration List a registration's OSS countries Email a registration's password to yourself

Reports

Start a report job Get a report job's status Get a report job's download link

Reports (Public)

Download a report via an emailed link

Tax Estimations

Estimate tax on a transaction

Transactions

List transactions Create a transaction Archive a transaction Export a transaction report Get an export's status List a filing's transactions Get connections' transaction date ranges List transaction sources Summarize transactions Get a transaction by id Update a transaction Update a credit note Update a transaction's addresses Get a transaction's backlink List related transactions Mark or unmark a transaction as tax-only

Users

List organization users List pending organization invitations Invite a user to an organization Revoke a pending organization invitation Update an organization user's role Remove a user from an organization

API reference / Upload an attachment

Upload an attachment

POST/attachments

Attach a document to a related entity in the resolved organization, as multipart/form-data with the file in the file part and relatedEntityId and relatedEntityType as form fields. Returns the stored attachment's metadata. Returns 404 if the related entity does not exist or belongs to an organization your credential cannot access. The file must be at most 10 MB.

Authorization

Api-KeystringRequired

Your secret API key. Include it with every request.

Headers

Api-Versiondate

Release date, as YYYY-MM-DD. Defaults to 2026-07-21.

Organization-Idstring

Target organization id (Organization-Id selector).

Connection-Idstring

Target connection id; resolves to its organization.

Entity-Idstring

Platform entity id; resolves to a connection's organization.

Entity-Sourcestring

Optional source to disambiguate an Entity-Id.

Response

idstringRequired

Kintsugi's unique identifier for the attachment.

fileNamestringRequired

Name the file was uploaded under.

contentTypestringRequired

Media type of the file.

sizeintegerRequired

Size of the file in bytes.

relatedEntityRelatedEntityRefRequired

The entity this attachment is held against.

uploadedAtstringRequired

When the attachment was uploaded, as an RFC-3339 UTC timestamp.

201

Successful Response

400

The request was invalid.

401

Authentication failed or was missing.

403

The credential is not permitted for this request.

404

The requested resource was not found.

409

The request conflicts with existing state.

413

The request body is larger than this endpoint accepts.

422

The request failed validation.

cURL

POST /attachments

-H "Api-Key: ***"

-H "Api-Version: 2026-07-21"

Response

{

"id": "atch_2mNpQr7Ls8f3k",

"fileName": "resale-certificate.pdf",

"contentType": "application/pdf",

"size": 20481,

"relatedEntity": {

"id": "exmp_2mNpQr7Ls8f3k",

"type": "EXEMPTION"

},

"uploadedAt": "2026-07-28T12:00:00Z"

}

Upload an attachment (2026-07-21) | Kintsugi API Reference