Add HTTP header

Description

Appends a value to the named header on the execution flow and returns the same headers instance. Has execution pins so the append order is deterministic. Header names are matched case-insensitively; multiple values for the same name preserve insertion order. Fails the pipeline if the headers came from an inbound request or response (read-only) — use make-http-headers to build a fresh collection.

When to use

Use Add HTTP header to attach a value to an HTTP headers collection. Chain multiple Add HTTP header nodes to build up a request header set, then wire the final output into the Headers input of HTTP request. To send the same header twice (e.g. multiple Set-Cookie values), call Add HTTP header twice with the same Name.

Pins

Input pins

Pin	Type	Default	Notes
Headers	HTTP headers	—	The headers collection to append to. Wire from Make HTTP headers or from a previous Add HTTP header to chain multiple values.
Name	string	—	The header name. Matched case-insensitively when reading values back.
Value	string	—	The header value to append. Adding the same name twice keeps both values in order.

Output pins

Pin	Type	Notes
Headers	HTTP headers	The same headers instance, now containing the appended value. Chain into another Add HTTP header to add more.

Execution pins

Pin	Direction
In	Input
Out	Output

Example

Send Accept: application/json and X-Trace-Id: <uuid> with an HTTP request. Wire Make HTTP headers into the Headers input of a first Add HTTP header (Name Accept, Value application/json); wire its Headers output into a second Add HTTP header (Name X-Trace-Id, Value from Random UUID); wire its Headers output into HTTP request.