{
  "schema_version": 2,
  "id": "commands/fcall_ro",
  "title": "FCALL_RO",
  "url": "https://redis.io/docs/latest/commands/fcall_ro/",
  "summary": "Invokes a read-only function.",
  "since": "7.0.0",
  "tags": [
    "docs",
    "develop",
    "stack",
    "oss",
    "rs",
    "rc",
    "oss",
    "kubernetes",
    "clients"
  ],
  "last_updated": "2026-09-18T09:48:32+01:00",
  "page_type": "content",
  "content_hash": "593c5a4c87a563fc6ac9662b0a9485929c56766e68b12384da59ba2a03bac1eb",
  "sections": [
    {
      "id": "overview",
      "title": "Overview",
      "role": "overview",
      "text": "This is a read-only variant of the [`FCALL`](https://redis.io/docs/latest/commands/fcall) command that cannot execute commands that modify data.\n\nFor more information about when to use this command vs [`FCALL`](https://redis.io/docs/latest/commands/fcall), please refer to [Read-only scripts](https://redis.io/docs/latest/develop/programmability#read-only_scripts).\n\nFor more information please refer to [Introduction to Redis Functions](https://redis.io/docs/latest/develop/programmability/functions-intro)."
    },
    {
      "id": "required-arguments",
      "title": "Required arguments",
      "role": "content",
      "text": "<details open><summary><code>function</code></summary>\n\nThe name of the function to call. It must be a read-only function.\n\n</details>\n\n<details open><summary><code>numkeys</code></summary>\n\nThe number of key names that follow. Arguments after the keys are passed as regular arguments.\n\n</details>"
    },
    {
      "id": "optional-arguments",
      "title": "Optional arguments",
      "role": "parameters",
      "text": "<details open><summary><code>key [key ...]</code></summary>\n\nThe key names the function accesses, provided to it via the Lua `KEYS` global variable. There must be exactly `numkeys` of them.\n\n</details>\n\n<details open><summary><code>arg [arg ...]</code></summary>\n\nAdditional arguments provided to the function via the Lua `ARGV` variable.\n\n</details>"
    },
    {
      "id": "redis-software-and-redis-cloud-compatibility",
      "title": "Redis Software and Redis Cloud compatibility",
      "role": "content",
      "text": "| Redis<br />Software | Redis<br />Cloud | <span style=\"min-width: 9em; display: table-cell\">Notes</span> |\n|:----------------------|:-----------------|:------|\n| <span title=\"Supported\">&#x2705; Standard</span><br /><span title=\"Supported\"><nobr>&#x2705; Active-Active</nobr></span> | <span title=\"Supported\">&#x2705; Standard</span><br /><span title=\"Supported\"><nobr>&#x2705; Active-Active</nobr></span> |  |"
    },
    {
      "id": "return-information",
      "title": "Return information",
      "role": "returns",
      "text": "**RESP2:**\n\nThe return value depends on the function that was executed.\n\n**RESP3:**\n\nThe return value depends on the function that was executed."
    }
  ],
  "examples": []
}