{
  "slug": "vercel-json-function-level-regions-configuration-2ab01c7d493b",
  "title": "vercel.json function-level regions configuration",
  "tools": [
    "vercel"
  ],
  "tags": [
    "agent"
  ],
  "introduced_at": "2026-02-10T18:27:02.000Z",
  "announced_at": "2026-02-10T18:27:02.000Z",
  "effective_at": null,
  "date_basis": "source-publication",
  "status": "unknown",
  "how": {
    "incantation": "When a function needs a specific deployment region, add a `regions` array to its entry under `functions` in `vercel.json`; that entry overrides the project-level `regions` setting for the matched function.",
    "examples": [
      "{\n  \"$schema\": \"https://openapi.vercel.sh/vercel.json\",\n  \"functions\": {\n    \"<function-path-or-glob>\": {\n      \"regions\": [\"<region-id>\"]\n    }\n  }\n}"
    ],
    "gotchas": [
      "Version: 50.14.1",
      "functions[<function-path-or-glob>] (required): Selects the function or functions receiving this configuration.",
      "functions[<function-path-or-glob>].regions (required): Array of region identifiers for the matched function; overrides the project-level `regions` setting for that function.",
      "Prerequisite: Use a supported region identifier. Hobby plans can select one region; Pro plans can use up to three; Enterprise plans can use multiple regions.",
      "Prerequisite: Redeploy the project for region configuration changes to take effect."
    ]
  },
  "why_it_matters": "Set a specific deployment region for a function in a Vercel project.",
  "sources": [
    "https://github.com/vercel/vercel/releases/tag/vercel%4050.14.1",
    "https://vercel.com/docs/functions/configuring-functions/region",
    "https://vercel.com/docs/project-configuration/vercel-json",
    "https://vercel.com/changelog/pro-customers-can-now-configure-up-to-3-regions-for-vercel-functions"
  ],
  "rank": 0.94015,
  "judge": {
    "publish": true,
    "judge_model": "codex-cli/gpt-6-luna+typesafe/jev-1.13.0",
    "prompt_version": "extract-v7+enrich-v2+judge-v2x3+jev-publish-v1"
  },
  "review_state": "approved",
  "provenance": {
    "run_id": "backfill-20261007",
    "verdict_id": "backfill-20261007:backfill-20261007-bb7802a6d4d72f58-0:gate",
    "evidence_hash": "620d5c07a7515b12b74d8f4af91f7f9c4ed6fddc14f5266f9f4d846b6d49a056"
  },
  "review": {
    "draft_hash": "5c58e2fe26d6c760ba04d8e4e4ad379a9bba75c26180e001b9b6a95044e606d2",
    "reviewer": "publication-gate",
    "reviewed_at": "2026-10-07T00:00:00.000Z",
    "decision": "backfill-20261007:gate",
    "reason": "2 of 3 judge runs approved with p_yes >= 0.9 (mean 0.94 >= 0.9; 2 needed) and Jev gave 0.75 (>= 0.6 needed)."
  }
}