ECHO

Returns the given string.

Browse all commands · Upstream source documentation

Reference field	Value
Canonical name	ECHO
Catalog group	Connection commands
Upstream since	1.0.0 — upstream Redis/module version, not an ffkv release
Pinned catalog	Redis 8.10.0

Syntax

ECHO message

ffkv behavior and limits

Connection state, selected database, authentication and protocol negotiation belong to the same persistent connection. RESP2 is the default; HELLO 3 selects RESP3. Streamed/unknown-length RESP3 frames are not supported.

Source: README.md:96–120, 391–395; tests/bdd/features/connections.feature.

All requests share the 8 MiB framing/1,024-argument ingress limit; normal RESP replies have 64 MiB wire/logical budgets with bounded nesting/value counts. Management and Lua origins impose smaller budgets. These are not a process RSS cap. Catalog inclusion is not exhaustive option or wire-format parity. See limits and compatibility.

Upstream metadata

The following fields come from the pinned Redis metadata, not measured ffkv performance or an assertion that ffkv enforces every upstream flag. Running COMMAND INFO/COMMAND DOCS describe the current engine.

Upstream Redis complexity: O(1)

Upstream arity: 2 (includes the command name; a negative number is a minimum).

Command flags: LOADING, STALE, FAST.

ACL categories: CONNECTION.

Argument structure

Argument	Type	Constraints / metadata
message	string	Required

Additional pinned upstream metadata

{
  "group": "connection",
  "since": "1.0.0"
}

Metadata source · Local snapshot: src/command_metadata.json, key echo.

BDD coverage and source examples

These are source observations, not a test run performed by this documentation build. A tag identifies scenario intent; an extracted vector identifies a command invocation, which may intentionally produce an error. Scenarios may require setup, multiple connections, persistence, cluster nodes or native-module fixtures.

• OFF suppresses wire replies while executing commands and SKIP affects exactly the next reply — tests/bdd/features/connections.feature:399; invocation observed.
• Binary echo and ping preserve payloads and QUIT closes the persistent socket — tests/bdd/features/connections.feature:751; command tag and invocation observed.

Extracted command vectors

The following JSON arrays are the test harness’s argument vectors, not shell commands. Numeric arguments are converted by the harness; objects of the form {"base64":"…"} represent decoded binary bytes, not a literal JSON command argument. Preserve scenario setup and connection ordering. See the CLI guide for shell quoting and binary stdin. No reply is invented or inferred.

OFF suppresses wire replies while executing commands and SKIP affects exactly the next reply — tests/bdd/features/connections.feature:435 (client “silent” sends:)

[
  "ECHO",
  "arrives"
]

Next source assertion: client “silent” receives:

"arrives"

Binary echo and ping preserve payloads and QUIT closes the persistent socket — tests/bdd/features/connections.feature:753 (client “closing” executes:)

Binary payload: decode the base64 object to bytes using a client API or binary stdin; do not send the base64 text as the value.

[
  "ECHO",
  {
    "base64": "AP8NCg=="
  }
]

Next source assertion: the reply equals:

{"type":"bytes","base64":"AP8NCg=="}

OFF suppresses wire replies while executing commands and SKIP affects exactly the next reply — tests/bdd/features/connections.feature:430 (client “silent” sends:)

[
  "ECHO",
  "must-not-arrive"
]