Concat

Concatenate multiple strings into one.

The Concat counter glues several pieces of text together into a single value. Each piece can be text you type or a nested counter. You mostly need it when another counter's option expects one value and you want that value built out of several parts.

Availability: every bot type. It makes no network requests, so it needs no API key and no environment variable when you self-host.

The Concat counter panel: a single Text list

Options

Option	What it does	Notes
Text list	The pieces that are joined together, in the order you list them.	Type into the Add text... box to append a piece, or pick a counter from it to nest one. There is no separator setting.

Every row of Text list takes a nested counter, and that counter can return anything: the bot turns numbers into text before joining them.

Concat itself nests in options such as:

• the Input text of a Replace counter,

• the URL (GET) of an HTTP counter, where part of the address comes from another counter,

• any option that takes one nested counter but you need several values in it.

What it returns

A single piece of text: every entry turned into text and stuck together in order. An empty Text list returns empty text.

Nothing is inserted between the items. A Text list of Online and 42 returns Online42, not Online 42. Add the separator as its own entry. It cannot be a space: what you type is trimmed, so a space adds nothing. Use visible text such as / instead.

Formatting

A Concat result is text, and the bot only formats numbers, so Use compact notation, Override default locale and Override default digits have no effect on it. That includes numbers produced inside the Concat counter: a Members counter nested in Text list contributes its raw value.

If you need a number formatted, keep Number or Math as the outermost counter instead, and type the surrounding text directly into the template. See Formatting counters.

Refresh and caching

Concat caches nothing. The bot works it out again on every channel update, every 10 minutes on the public bot and every 5 minutes on the other bot types. Anything nested inside it keeps its own refresh behaviour. See How counters update.

Examples

Building a URL

An HTTP counter takes a single URL (GET). To put a value from another counter into the middle of that address, build the address with Concat and nest the Concat counter in the URL (GET) field.

Text list, in order:

1. https://api.example.com/v1/stats?server=

2. a nested counter that returns the identifier you need

3. &format=json

The HTTP counter then receives one finished address.

Joining values with a separator

Because nothing is inserted automatically, the separator is just another entry.

Text list, in order:

1. a nested Members counter with no filters

2. /

3. a nested Members counter with Filter by status set to Online + Idle + DND

That returns something like 120/47.

Errors

Concat has no errors of its own. What can still go wrong:

What you see	What to do
The channel shows ERROR!	A counter nested inside Text list failed, so the whole template failed. Open the channel in the dashboard and read the error to find the counter at fault.
The result for the channel name is less than 2 characters long.	A voice or category channel name needs at least 2 characters, and an empty Text list is the usual reason. Fill Text list, or add text around the counter in the template.

A very long result is cut off rather than failing.

If it still fails, Troubleshooting covers the common causes, and you can ask on the support server.

Technical details

• Evaluator: packages/services/src/DataSource/DataSourceEvaluator/evaluators/concat.ts. Entries are stored in options.strings as literals or nested counter objects, turned into text with String() and joined onto an empty-string seed, which is why an empty list returns empty text instead of failing and why the counter itself can never throw.

• Only numbers go through the result formatter; a string result is returned untouched, which is why the formatting options do nothing here.

• A whitespace-only entry is trimmed before it is stored, so it never becomes a row.

• Global limits: 60 s per counter in the template, shared with everything nested inside it (EVALUATION_TIMEOUT), 50,000 tree-exploration iterations, and a final result that is trimmed and then cut to 1023 characters for a topic or 99 for a channel name, with the 2-character minimum (EVALUATION_RESULT_FOR_CHANNEL_NAME_IS_LESS_THAN_2_CHARACTERS) checked before the cut.

• When a nested counter makes the template fail, the update job writes jobs.updateChannels.computeError into the name or topic: ERROR! in en-US, translated in the other locales.

• No network access, no cache entry and no environment variable when self-hosting.