infochanged

Workflows, Workers - Create Workflow instance batches by count or list

Announced: 2026-10-08
Tags: Workflows, Workers
Severity: info, set by reef/rss-rule-v1
Source: https://developers.cloudflare.com/changelog/post/2026-10-08-create-batch-object-form/

<a href="https://developers.cloudflare.com/workflows/build/workers-api/#createbatch"><code>createBatch()</code></a> now accepts an options object that creates up to 100 Workflow instances in one call. The result lists the created instances and explains why any others were not created. To use this form in local development and get its types from <code>wrangler types</code>, use Wrangler 4.148.0 or later. To create instances that share the same options, pass <code>count</code>. Each instance receives a generated ID: <div><div data-nb-tabs data-nb-sync-key="workersExamples" class><div class="relative flex border-b border-border" role="tablist" data-nb-tabs-list></div><div class="mt-3"><div role="tabpanel" data-nb-tabs-content data-nb-tab-label="JavaScript" class><figure class="nb-code-figure" data-nb-lang="js"><pre class="astro-code astro-code-themes github-light github-dark nb-shiki-c6xiwz" tabindex="0" data-language="js" data-nb-lang="js"><code>const result = await env.MY_WORKFLOW.createBatch({ count: 10, params: { report: "daily" }, });</code></pre></figure></div><div role="tabpanel" data-nb-tabs-content data-nb-tab-label="TypeScript" class><figure class="nb-code-figure" data-nb-lang="ts"><pre class="astro-code astro-code-themes github-light github-dark nb-shiki-c6xiwz" tabindex="0" data-language="ts" data-nb-lang="ts"><code>const result = await env.MY_WORKFLOW.createBatch({ count: 10, params: { report: "daily" }, });</code></pre></figure></div></div></div><script type="module" src="https://developers.cloudflare.com/home/runner/work/cloudflare-docs/cloudflare-docs/src/components/ui/tabs/Tabs.astro?astro&type=script&index=0&lang.ts"></script></div> To give each instance its own ID or options, pass <code>instances</code>: <div><div data-nb-tabs data-nb-sync-key="workersExamples" class><div class="relative flex border-b border-border" role="tablist" data-nb-tabs-list></div><div class="mt-3"><div role="tabpanel" data-nb-tabs-content data-nb-tab-label="JavaScript" class><figure class="nb-code-figure" data-nb-lang="js"><pre class="astro-code astro-code-themes github-light github-dark nb-shiki-c6xiwz" tabindex="0" data-language="js" data-nb-lang="js"><code>const { created, errors } = await env.MY_WORKFLOW.createBatch({ instances: [ { id: "order-1", params: { orderId: 1 } }, { id: "order-2", params: { orderId: 2 } }, ], }); for (const error of errors) { console.log(error.index, error.id, error.code, error.message); }</code></pre></figure></div><div role="tabpanel" data-nb-tabs-content data-nb-tab-label="TypeScript" class><figure class="nb-code-figure" data-nb-lang="ts"><pre class="astro-code astro-code-themes github-light github-dark nb-shiki-c6xiwz" tabindex="0" data-language="ts" data-nb-lang="ts"><code>const { created, errors } = await env.MY_WORKFLOW.createBatch({ instances: [ { id: "order-1", params: { orderId: 1 } }, { id: "order-2", params: { orderId: 2 } }, ], }); for (const error of errors) { console.log(error.index, error.id, error.code, error.message); }</code></pre></figure></div></div></div></div> <code>created</code> contains the created instances. <code>errors</code> contains each entry that was not created, identified by its position in the input. IDs that already exist and IDs repeated within the batch are reported as errors instead of being skipped silently. Passing an array to <code>createBatch()</code> is deprecated. Existing code that uses the array form continues to work. For more information, refer to <a href="https://developers.cloudflare.com/workflows/build/workers-api/#createbatch"><code>createBatch</code></a>.

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