What causes "keyword argument repeated: `endpoint`" in leptos-rs/leptos?

Delete the extra `endpoint = ...` entry, keeping only the desired path.

keyword argument repeated: `endpoint`

Error message

keyword argument repeated: `endpoint`

What it means

The #[server] macro parser throws this when the `endpoint` keyword argument is specified more than once. `endpoint` sets the custom function path (fn_path); a second occurrence is ambiguous, so compilation fails with a span pointing at the repeated key.

Source

Thrown at server_fn_macro/src/lib.rs:1105

                    } else if key == "prefix" {
                        if prefix.is_some() {
                            return Err(syn::Error::new(
                                key.span(),
                                "keyword argument repeated: `prefix`",
                            ));
                        }
                        prefix = Some(stream.parse()?);
                    } else if key == "encoding" {
                        if encoding.is_some() {
                            return Err(syn::Error::new(
                                key.span(),
                                "keyword argument repeated: `encoding`",
                            ));
                        }
                        encoding = Some(stream.parse()?);
                    } else if key == "endpoint" {
                        if fn_path.is_some() {
                            return Err(syn::Error::new(
                                key.span(),
                                "keyword argument repeated: `endpoint`",
                            ));
                        }
                        fn_path = Some(stream.parse()?);
                    } else if key == "input" {
                        if encoding.is_some() {
                            return Err(syn::Error::new(
                                key.span(),
                                "`encoding` and `input` should not both be \
                                 specified",
                            ));
                        } else if input.is_some() {
                            return Err(syn::Error::new(
                                key.span(),
                                "keyword argument repeated: `input`",
                            ));
                        }

View on GitHub (pinned to 32d20f6c9d)

Solutions

Delete the extra `endpoint = ...` entry, keeping only the desired path.
If different endpoints are needed, declare separate #[server] functions instead.
Audit any macro wrapper so it only adds endpoint when absent.

Example fix

// before
#[server(endpoint = "/api/save", endpoint = "/api/save-v2")]
async fn save(data: String) -> Result<(), ServerFnError> { todo!() }

// after
#[server(endpoint = "/api/save-v2")]
async fn save(data: String) -> Result<(), ServerFnError> { todo!() }

Defensive patterns

Strategy: validation

Validate before calling

// Pre-commit check for duplicate `endpoint` args in #[server]:
// grep -rnE '#\[server\([^)\n]*endpoint\s*=[^)\n]*endpoint\s*=' src/ && exit 1 || exit 0

Prevention

Declare only one endpoint path per server function.
Need different paths? Create separate #[server] functions rather than stacking endpoint args.
Keep endpoint paths centralized (constants) to avoid hand-editing duplicates.
Run cargo check/clippy in CI to catch macro parse errors early.

When it happens

Trigger: Writing #[server(...)] with two `endpoint = "..."` entries, e.g. #[server(endpoint = "/a", endpoint = "/b")], or a macro wrapper that injects endpoint while the user also wrote one.

Common situations: Copy-paste of attribute args, merging two annotations during refactoring, or macro_rules! layers that each add an endpoint.

Related errors

AI-assisted analysis of leptos-rs/leptos@32d20f6c9d (2026-09-01). Data as JSON: /api/errors/7f9524f29c22a198. Report an issue: GitHub.