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The node browser

Every field that takes an OPC UA address — NodeId, ObjectId, MethodId, the file node's target — uses the same control. It has three parts, left to right:

[ ? ▾ ][ ns= ]  ns=2;s=Boiler.Temperature   [ 🔍 ][ ⚗ ]
   |      |            |                       |    |
 source notation     value                 browse verify

The prefix: two stops​

The prefix answers two orthogonal questions, so it has two buttons.

The source menu

Stop 1 — the source. Who decides the target at runtime. Four states, each with its own glyph:

GlyphStateMeaning
amber ?not setNobody has answered yet. The message still wins, as it always did.
a node outlinethis nodeThe configured value is always used.
{ }this node, templatedThe value is a template the message fills in.
an envelopethe messageThe field is a message path, not an address.

The envelope is the one to remember: in Node-RED a msg is an envelope carrying payload and topic, so the glyph says the envelope decides the target.

Full behaviour in Where does the NodeId come from?.

The notation menu, each entry showing the characters its value begins with

Stop 2 — the notation. How the address is written. Instead of an icon, each notation shows the characters its value begins with, so the button and the field agree:

TokenNotationExample
abctext (not verified)Boiler.Temperature
ns=NodeIdns=2;s=Boiler.Temperature
na=Aliased NodeIdna=boiler;s=Temperature
nsu=NodeId with namespace Urnnsu=urn:sterfive:boiler;s=Temperature
/BrowsePath/2:Boiler/2:Temperature
/a:Aliased Browse Path/boiler:Boiler/boiler:Temperature

The notation the field is already in is detected as you type, so the token usually looks after itself. Picking one explicitly rewrites the value into that notation — which is the quickest way to convert a NodeId into a browse path or back.

Choosing a notation also answers the source question: writing your value a particular way implies the value is yours, so the source moves to this node.

The notation you pick is remembered

The last notation you chose is reused for the next field you fill in, so a team that works in browse paths does not have to switch every time. It is a per-browser preference and never changes how an existing node behaves. New, empty fields start on ns=.

It follows your editor theme​

The control takes its colours from Node-RED's own theme variables, so it follows whatever theme the editor is set to — including community themes it knows nothing about.

The same control in a dark editor theme

Browse and verify​

These two buttons exist only under this node.

That is not an arbitrary restriction — it falls out of what they do. Both act on a literal address that this node owns:

  • under the message the field is a pointer; there is nothing to browse to and nothing to verify;
  • under templated the address is not complete until a message renders it;
  • under not set the node does not own the value yet — that is exactly the unanswered question.

Under this node, both tools are present

So on a flow saved before 3.40 the buttons are absent until you pick a source. Answering takes one click, and the tools appear.

Browse — the address-space tree​

Opens a live tree of the server's address space, rooted at Objects.

  • Quick filter — type to narrow the loaded tree; matching branches stay visible and the first match is focused.
  • Keyboard — arrows to move, Enter to pick, Escape to close.
  • No deploy needed — the tree can be browsed before the endpoint has been deployed, so you can wire and configure a flow in one pass.
  • Picking a node writes a browse path by default and sets the source to this node.

Verify​

Resolves the value against the server and reports what it found — the NodeId, the browse path, the node class, and the aliased forms. Use it to confirm an address you typed by hand, or to see the equivalent notations for one you browsed to.

msg. mode​

The message mode

When the source is the message, the field turns into a path editor:

  • msg. is shown in clear against the field, so the path reads as what it is;
  • the notation stop disappears — a pointer has no notation;
  • the field suggests the paths this node honours first, then other common message properties (payload, payload.nodeId, payload.value, topic, nodeId, objectId, methodId);
  • it stays free text — the list is a shortcut, not a closed set, so a flow can carry the address wherever it likes.

Whatever is found at the path is used as-is. A path pointing at an array of NodeIds drives a multi-node read or an array subscription with no further configuration.

See also​