Cell References

A cell reference is a {{Tab!Ref}} placeholder you put inside an api source's request. When the automation runs, Sheetgo reads that cell from the automation's Google Sheets destination and substitutes the value before the request goes out — so the request changes as your sheet changes, with no API call needed.

GET https://api.example.com/events?since={{Log!A:last|date|fmt:iso_dt}}

Which {{ }} am I looking at?

Three unrelated syntaxes share the double-brace shape. They are not interchangeable.

Syntax Example Where it works
Cell reference {{Sheet1!A1|date|fmt:iso_d}} api source — endpoint, headers, body
Smart tag {{Customer}} document, share, mail_merge destinations
Body template {{DATA}}, {{for row in ROWS}} webhook destination body

A cell reference always contains a !. A smart tag is a bare column name. The body template uses the reserved names DATA and ROWS and the block tags {{for}}, {{if}} and {{except-last}}.

Grammar

{{ <tab>!<ref> [|<filter>]* }}

Filters

Render mode — must be the first filter if used. Default is F.

Filter Value you get Cell displaying $1,234.50
F (default) the formatted display text "$1,234.50"
U the raw underlying value 1234.5

F and U after another filter are invalid, and the placeholder is left as literal text.

String — trim (strip whitespace), upper, lower.

Numeric — int, float. Both fail the run on a non-numeric value.

Date input — promote the value to a date, always doing work:

Filter Behaviour
date auto-detect, US-leaning on ambiguous input
date_us month first — 01/02/2026 is 2 January
date_eu day first — 01/02/2026 is 1 February
date_iso strict ISO 8601 only

Accepts strings, Sheets serial numbers, and existing dates. On its own a date filter renders ISO datetime; chain a fmt:* to change that.

Date output — fmt:*, a no-op unless a date input filter came first:

fmt:day, fmt:month, fmt:year, fmt:timestamp (Unix seconds), fmt:timestamp_ms (Unix milliseconds), fmt:serial (Sheets serial), fmt:iso_dt, fmt:iso_d, fmt:us_dt, fmt:us_d, fmt:eu_dt, fmt:eu_d. _dt includes the time, _d is date only.

Where they go

Location Substitution
endpoint URL-encoded per component. Keep placeholders out of the scheme and host.
headers verbatim, with CR/LF stripped
body verbatim, no escaping — you are responsible for valid JSON. "{{A1}}" yields a quoted string; {{A1|U}} unquoted yields a bare JSON value.

When something goes wrong

Situation Behaviour
Invalid syntax, unknown filter, unbalanced braces treated as literal text — your API receives the raw {{...}}
Tab does not exist run fails, naming the placeholder and its location
Empty cell, out-of-bounds cell, :last on an empty column substituted as "", warning logged, run continues
Numeric or date conversion fails run fails
Network failure reading the sheet retried 3× with backoff, then the run fails

⚠️ Requires a Google Sheets destination

Substitution reads from the automation's destination, so it only happens when that destination is a Google Sheets file. With any other destination the placeholders are sent to your API as literal text, with no warning.

⚠️ Never resolves alongside a webhook destination

A webhook destination must be an automation's only destination, so such an automation has no Sheets destination to read from. Cell references in it will always be sent literally. Pair cell references with a file destination instead.

More: start page https://dev-api.sheetgo.com/rest/reference.md, everything in one file https://dev-api.sheetgo.com/rest/llms-full.txt, OpenAPI https://dev-api.sheetgo.com/rest/openapi.json.