Add a variant to a product, under the same rules as creation

POST /products/{productId}/variants

Appends inventory.variant-added. Idempotent on the SKU: a retried add meets 409 VariantSkuConflict, never a second variant.

Access

Requires products:write.

How scopes come from roles: Scopes and roles. Getting a token: Authentication and app tokens.

Retries

Idempotent on the SKU: a retried add meets 409 VariantSkuConflict, never a second variant.

A retry with the same key answers 201, with what the first call recorded.

Why every write carries a key: Idempotency and retries.

Facts appended

inventory.variant-added

What a fact is: Facts and the journal.

AI agent tool

Agents call this as catalog_add_variant (Catalog: Add variant), in the catalog toolset.

Connecting an agent: AI agents.

Example

Add the green widget; WIDGET-GREEN is already a stocked item.

curl

curl -X POST 'https://inventory.getmanifold.io/products/prd_019cd54b-2e40-7921-ac50-698c7db3cbeb/variants' \
  -H "Authorization: Bearer $MANIFOLD_TOKEN" \
  -H 'Content-Type: application/json' \
  -d '{
  "sku": "WIDGET-GREEN",
  "options": [
    {
      "name": "Colour",
      "value": "Green"
    }
  ],
  "kind": {
    "_tag": "stocked"
  }
}'

JavaScript (fetch)

const response = await fetch("https://inventory.getmanifold.io/products/prd_019cd54b-2e40-7921-ac50-698c7db3cbeb/variants", {
  method: "POST",
  headers: { Authorization: `Bearer ${process.env.MANIFOLD_TOKEN}`, "Content-Type": "application/json" },
  body: JSON.stringify({
    "sku": "WIDGET-GREEN",
    "options": [
      {
        "name": "Colour",
        "value": "Green"
      }
    ],
    "kind": {
      "_tag": "stocked"
    }
  }),
});
if (!response.ok) throw new Error(`${response.status}: ${await response.text()}`);
const answer = await response.json();

Request body · application/json

{
  "sku": "WIDGET-GREEN",
  "options": [
    {
      "name": "Colour",
      "value": "Green"
    }
  ],
  "kind": {
    "_tag": "stocked"
  }
}

Response · 201 · application/json

{
  "id": "prd_019cd54b-2e40-7921-ac50-698c7db3cbeb",
  "title": "Widget",
  "description": "A moulded widget for everyday fixing jobs. Dishwasher safe.",
  "status": "active",
  "handle": "widget",
  "vendor": "Tidewater Supply Co.",
  "productType": "Widgets",
  "tags": [
    "Hardware",
    "Bestseller"
  ],
  "seo": {
    "title": "Widget — moulded, dishwasher safe"
  },
  "taxClass": "standard",
  "options": [
    {
      "name": "Colour",
      "values": [
        "Blue",
        "Red",
        "Green"
      ]
    }
  ],
  "variants": [
    {
      "id": "var_019cd54b-2e4a-7ee1-b04a-3bb14b60736f",
      "sku": "WIDGET-BLUE",
      "options": [
        {
          "name": "Colour",
          "value": "Blue"
        }
      ],
      "kind": {
        "_tag": "stocked"
      },
      "createdAt": "2026-03-10T01:10:00.000Z",
      "updatedAt": "2026-03-10T01:10:00.000Z"
    },
    {
      "id": "var_019cd54b-2e54-72b7-ae20-2d04347601b0",
      "sku": "WIDGET-RED",
      "options": [
        {
          "name": "Colour",
          "value": "Red"
        }
      ],
      "kind": {
        "_tag": "stocked"
      },
      "createdAt": "2026-03-10T01:10:00.000Z",
      "updatedAt": "2026-03-10T01:10:00.000Z"
    },
    {
      "id": "var_01a15c72-67e0-79db-818b-f233786beac6",
      "sku": "WIDGET-GREEN",
      "options": [
        {
          "name": "Colour",
          "value": "Green"
        }
      ],
      "kind": {
        "_tag": "stocked"
      },
      "createdAt": "2026-10-21T03:12:44.000Z",
      "updatedAt": "2026-10-21T03:12:44.000Z"
    }
  ],
  "createdAt": "2026-03-10T01:10:00.000Z",
  "updatedAt": "2026-10-21T03:12:44.000Z"
}

The panel writes this call in other languages. It does not send it: Manifold's APIs do not take calls from a web page on another site, so run the call from your own code or terminal. The whole API as OpenAPI: inventory-manager.openapi.json. Base URL https://inventory.getmanifold.io.

Errors

Every refusal is a status and a JSON body whose _tag names it. A refused call changes nothing. Some can answer a retry of a call that already worked: they are marked.

`401`

Refusal	What it means	What to do
`Unauthorized` reason	The token is missing, expired or not one Manifold issued.	Get a fresh token and send the call again.
`TokenAlreadyUsed` tokenId	A single-use app token was already spent.	Mint a new token for this call.

`402`

Refusal	What it means	What to do
`SubscriptionRequired` status	The organization's subscription has lapsed, so writes are refused.	An owner settles billing. Reads still work meanwhile.

`403`

Refusal	What it means	What to do
`TenantRequired` userId	The token names no organization.	Choose the organization, then get a new token.
`ScopeRequired` required	The token's roles do not grant the scope this call needs.	Ask an owner or admin for a role that grants it.

`404`

Refusal	What it means	What to do
`ProductNotFound` productId	No such record in this organization.	Check the id in the path or the body.

`409`

Refusal	What it means	What to do
`ProductArchived` productId	The product is archived, and an archived product takes no changes.	Use a product that is not archived.
`VariantSkuConflict` sku, productId Can answer a retry	The SKU already belongs to another product's variant.	If this answers a retry, your first call probably landed. Use another SKU.
`SkuNotStocked` sku	The SKU is not stocked: it is a service or a kit, which holds no units.	Use a stocked SKU.
`CompositeSkuIsStocked` sku	A stocked SKU cannot become a kit.	Use a new SKU for the kit.
`SkuNotAllowed` sku, alphabet, allowed	The SKU has characters this organization's SKU alphabet does not allow. `allowed` lists them.	Change the SKU, or an owner widens the alphabet in Settings › General.
`VariantOptionsInvalid` productId, sku, reason	The variant's options do not fit the product's options. `reason` says how.	Send an option value for each of the product's options.
`BarcodeConflict` barcode, sku	Another SKU already has this barcode. `sku` names it.	Use another barcode, or take it off the other SKU first.
`MirroredFromSource` source	This area is fed by your source system until the organization goes live.	Make the change in the source system, or go live first.

`503`

Refusal	What it means	What to do
`RequestLogUnavailable` tokenId, reason	The service could not record the request, so it did nothing.	Send the same request again, with the same key.

How refusals work everywhere: Errors.