Fix Vitest 5 test.sequential Removed Error

Why this got removed instead of deprecated

concurrent and sequential described the same thing from two directions. A test was either allowed to run concurrently with its siblings or it wasn’t, and sequential only ever meant “not concurrent.” Vitest’s own migration guide states the removal directly, in the section covering these removed options:

Vitest 5.0 removes the deprecated test.sequential, describe.sequential, and sequential test options. Use concurrent: false when you need a test or suite to opt out of inherited or globally configured concurrency.

The redundancy is what made this a removal candidate rather than a permanent pair of options. The GitHub issue that proposed this change lists out the full set of ways Vitest let you express test concurrency, including combinations like { sequential: false }, and points out that having two independent flags that can contradict each other (is { concurrent: false, sequential: false } concurrent or not?) creates internal churn and reader confusion for no real benefit. Collapsing to one flag, concurrent, removes the ambiguity entirely.

Fix it: switch to concurrent: false

Vitest’s migration guide documents the exact replacement pattern for all three removed forms. Each is a mechanical rename, not a behavior change.

test.sequential("example", async () => {
  /* ... */
}); // BROKEN: test.sequential no longer exists in Vitest 5

test("example", { concurrent: false }, async () => {
  /* ... */
}); // FIXED: same effect, using the surviving option

describe.sequential follows the identical pattern:

describe.sequential("suite", () => {
  /* ... */
}); // BROKEN: describe.sequential no longer exists in Vitest 5

describe("suite", { concurrent: false }, () => {
  /* ... */
}); // FIXED: same effect, using the surviving option

If your code used the sequential option-object key instead of the chained method, the same replacement applies directly to that key:

test("example", { sequential: true }, async () => {
  /* ... */
}); // BROKEN: sequential key no longer recognized

test("example", { concurrent: false }, async () => {
  /* ... */
}); // FIXED: negate the surviving flag instead

Search your suite for .sequential( and sequential: before you upgrade, not after. Every match needs this exact rename, and there’s no runtime compatibility shim carrying the old name forward.

Confirmed version range

Documented in Vitest’s own current migration guide as an intentional Vitest 5.0 removal, in the section covering the removed sequential options. Corroborated by vitest-dev/vitest#10180, the issue that proposed consolidating concurrency into the single concurrent flag. This repository’s own vitest.config.ts is pinned to vitest@^3.0.0, so this removal wasn’t independently reproduced against this project’s build; every claim above traces back to Vitest’s migration guide and the linked issue, not a local repro.

More fixes like this one are in the Guides & Fixes archive, and every Vitest post is tagged under vitest. If your suite is also hitting the hoisted-mocking change in the same upgrade, see Fix Vitest 5 vi.mock Top-Level Scope Error. Running vitest from a subdirectory in the same upgrade? See Fix Vitest 5 Config Not Found in Parent Directory.