# `Otel.Trace.SpanKind`
[🔗](https://github.com/yangbancode/otel/blob/main/lib/otel/trace/span_kind.ex#L1)

SpanKind — clarifies the relationship between Spans (spec
`trace/api.md` §SpanKind, Status: **Stable**).

Describes two independent properties:

- **Call direction**: outgoing (`:client` / `:producer`) vs
  incoming (`:server` / `:consumer`), or neither (`:internal`).
- **Communication style**: request/response (`:client` /
  `:server`) vs deferred execution (`:producer` / `:consumer`).

`:internal` is the spec default when a Span is created without
an explicit kind (spec `trace/api.md` L397: *"default to
`SpanKind.Internal` if not specified"*). That default is applied
at Span creation, not by this type module.

## Values

| SpanKind    | Call direction | Communication style |
|-------------|----------------|---------------------|
| `:client`   | outgoing       | request/response    |
| `:server`   | incoming       | request/response    |
| `:producer` | outgoing       | deferred execution  |
| `:consumer` | incoming       | deferred execution  |
| `:internal` | —              | — (default)         |

## References

- OTel Trace API §SpanKind: `opentelemetry-specification/specification/trace/api.md` L741-L801

# `t`

```elixir
@type t() :: :internal | :server | :client | :producer | :consumer
```

One of the five SpanKind atoms defined by OTel Trace API §SpanKind
(`trace/api.md` L773-L791).

- `:server` — server-side handling of a remote request while the
  client awaits a response (spec L775-L776).
- `:client` — a request to a remote service where the client
  awaits a response; usually becomes a parent of a remote
  `:server` span when propagated (spec L777-L780).
- `:producer` — initiation or scheduling of a local or remote
  operation; often ends before the correlated `:consumer` span
  (spec L781-L786).
- `:consumer` — processing of an operation initiated by a
  producer, where the producer does not wait for the outcome
  (spec L787-L788).
- `:internal` — default; internal operation within an
  application (spec L789-L791).

---

*Consult [api-reference.md](api-reference.md) for complete listing*