The {{...}} placeholder syntax lets you pull live values from your destination Google Sheet into any part of an API Source request — URL, headers, or body — at the moment the connection runs.

Where this works: API Source connections whose destination is a Google Sheets file. Connections writing to Excel, BigQuery, CSV, Dropbox, etc. ignore the syntax — placeholders are sent as literal {{...}} text.

New to A1 Notation? Start with the Basic Guide first.

1. Syntax at a glance

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

{{ and }} — double braces (always two on each side).
<tab> — the worksheet (tab) name in your destination spreadsheet.
! — separator between tab name and cell reference.
<reference> — a cell like A1 or the special form A:last.
|<filter> — optional; chain as many as you need, applied left-to-right.

Placeholder	Meaning
`{{Sheet1!A1}}`	Cell A1 of Sheet1, formatted display value (default).
`{{Sheet1!A:last}}`	Last non-empty cell in column A of Sheet1.
`{{'My Sheet'!B7}}`	Tab name with a space — must be wrapped in single quotes.
`{{Sheet1!A1\|U}}`	Cell A1 as the raw (unformatted) value.
`{{Sheet1!A1\|date\|fmt:iso_d}}`	Parse A1 as a date, output as ISO date.
`{{Sheet1!A1\|trim\|upper}}`	Cell A1 trimmed and uppercased.

2. Tab names

Tab name	Placeholder example
Letters, digits, underscore (no spaces)	`{{Sheet1!A1}}`, `{{my_tab!A1}}`
Contains a space or special character	`{{'My Sheet'!A1}}`, `{{'2026 Sales'!A1}}`
Contains a literal apostrophe	Double it: `{{'O''Brien'!C3}}`

When in doubt, always wrap the tab name in single quotes — that form works for any name.

3. Cell references

Form	What it returns
`A1`, `B7`, `AB42`	A single cell.
`A:last`	The single cell in column A at the last non-empty row in that column.

Only single cells are supported. Ranges like A1:B5 are not supported. The column letter and last keyword are case-insensitive.

4. Render mode (first filter, if used)

Controls how the cell value is read from Google Sheets. If omitted, defaults to F.

Filter	What you get	Example: cell formatted as $1,234.50
`F` (default)	Exactly what the cell displays — locale-aware, formatted text.	`"$1,234.50"`
`U`	Raw underlying value: numbers as numbers, booleans as TRUE/FALSE.	`1234.5`

Note: F or U must be the first filter if used. {{Sheet1!A1|trim|U}} is invalid and will be left as literal text.

5. String filters

Filter	Effect	Example
`trim`	Removes leading and trailing whitespace.	`" hi " → "hi"`
`upper`	Uppercases the string.	`"hello" → "HELLO"`
`lower`	Lowercases the string.	`"Hello" → "hello"`

6. Numeric filters

Filter	Effect
`int`	Convert to integer. Truncates toward zero. TRUE→1, FALSE→0.
`float`	Convert to float.

Warning: |int and |float fail loudly (stop the run) if the value is not numeric. For example, |int on "abc" is an error.

7. Date input filters

These filters parse the cell value into a date. They fail loudly if parsing isn't possible.

Filter	What it does
`date`	Auto-detect format (US-leaning on ambiguous dates like 01/02/2026 → Jan 2).
`date_us`	Force US interpretation (month first). 01/02/2026 → January 2.
`date_eu`	Force EU interpretation (day first). 01/02/2026 → February 1.
`date_iso`	Strict ISO 8601 only (e.g. 2026-05-06).

By itself, a date filter outputs an ISO datetime (e.g. 2026-05-06T14:30:45). To get a different format, chain a fmt:* filter after it.

8. Date output filters — fmt:*

Format a date that has already been parsed. Always chain after a date input filter — used alone they are a no-op.

All examples assume parsed datetime: 2026-05-06 14:30:45

Filter	Output
`fmt:day`	`6`
`fmt:month`	`5`
`fmt:year`	`2026`
`fmt:timestamp`	`1778025600` (Unix seconds, 10 digits)
`fmt:timestamp_ms`	`1778025600000` (Unix ms, 13 digits — JS/Java)
`fmt:serial`	`46148.0` (Google Sheets serial)
`fmt:iso_dt`	`2026-05-06T14:30:45`
`fmt:iso_d`	`2026-05-06`
`fmt:us_dt`	`05/06/2026 02:30:45 PM`
`fmt:us_d`	`05/06/2026`
`fmt:eu_dt`	`06/05/2026 14:30:45`
`fmt:eu_d`	`06/05/2026`

Mnemonic: _dt = datetime (with time), _d = date only.

9. Where placeholders go in a request

URL — automatically URL-encoded. Keep placeholders in the path or query string, not in the scheme or hostname.

https://api.example.com/products/{{Sheet1!A1}}
https://api.example.com/search?q={{Sheet1!B2}}&limit=10

Headers — substituted verbatim (CR/LF stripped).

Authorization: Bearer {{Sheet1!A1}}

Body — substituted verbatim, no automatic escaping. You are responsible for placing the placeholder correctly inside your JSON/XML/form body.

{ "year": "{{Sheet1!A1}}" }   ← becomes: { "year": "2026" }
{ "year": {{Sheet1!A1|U}} }   ← becomes: { "year": 2026 }  (unquoted)

Warning: If the cell value contains a " character and you place the placeholder inside a JSON string, the result will be invalid JSON. The system does not auto-escape. Use |trim or preprocess your data if needed.

10. Full examples

Filter products by year stored in a config tab

{ "filter": { "year": { "gte": "{{Config!B2}}" } } }
→ { "filter": { "year": { "gte": "2024" } } }

Use the most recent date in a column as a "since" parameter

https://api.example.com/events?since={{Log!A:last|date|fmt:iso_dt}}
→ https://api.example.com/events?since=2026-05-06T14%3A30%3A45

Mix US-formatted dates from a sheet into an EU-format API

{ "from": "{{Reports!A1|date_us|fmt:eu_d}}" }
→ { "from": "31/12/2025" }  (if Reports!A1 = 12/31/2025)

Tenant ID + auth token from config

URL:    https://api.example.com/tenants/{{Config!A1}}/users
Header: Authorization: Bearer {{Config!B1|trim}}

11. What is not supported

What you tried	Result
`{{Sheet1!A1:B5}}` (range)	❌ Only single cells supported.
`{{My Sheet!A1}}` (space, no quotes)	❌ Treated as literal text. Use `{{'My Sheet'!A1}}`.
`{{Sheet1!A1\|trim\|U}}` (render mode not first)	❌ Treated as literal text. Use `{{Sheet1!A1\|U\|trim}}`.
`{Sheet1!A1}` (single braces)	❌ Not recognized.
`{{Sheet1!A1\|fmt:iso_d}}` (fmt without date input)	No-op — value passes through unchanged.
Destination is not Google Sheets	Placeholders sent as literal text, no warning.

12. What happens when something goes wrong

Situation	Behaviour
Invalid syntax / unknown filter	Treated as literal text — run continues, your API receives `{{...}}`.
Tab name doesn't exist	Run fails with a clear error naming the placeholder.
Cell is empty	Substituted as empty string `""` + warning logged. Run continues.
Cell out of grid bounds	Substituted as `""` + warning. Run continues.
`:last` on an empty column	Substituted as `""` + warning. Run continues.
Numeric or date conversion fails	Run fails with a clear error.
Network failure reading the sheet	Retries up to 3 times with exponential backoff before failing.

13. Quick-reference cheat sheet

{{ <tab>!<ref> [|<filter>]* }}REF     : A1, AB42, A:last (case-insensitive)
TAB     : Sheet1, my_tab, 'Quoted Name', 'O''Brien'RENDER (must be 1st if used; default = F)
  F     formatted display value
  U     raw underlying valueSTRING
  trim  strip whitespace
  upper uppercase
  lower lowercaseNUMERIC
  int   to integer (errors on non-numeric)
  float to float   (errors on non-numeric)DATE INPUT
  date      auto-detect
  date_us   US (month first)
  date_eu   EU (day first)
  date_iso  strict ISO 8601DATE OUTPUT (no-op without a date input)
  fmt:day / fmt:month / fmt:year
  fmt:timestamp     Unix seconds (10 digits)
  fmt:timestamp_ms  Unix milliseconds (13 digits)
  fmt:serial        Sheets serial
  fmt:iso_dt / fmt:iso_d
  fmt:us_dt  / fmt:us_d
  fmt:eu_dt  / fmt:eu_d

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A1 Notation in API Source — Basic Guide

A1 Notation in API Source — Advanced Guide