Sheet-driven invoice reminder. Reads an InvoiceLog Sheet, sends personalized reminder emails for overdue invoices with escalating tone (friendly → follow-up → final), stamps each row to prevent duplicate chases. Replaces the thin CSV-driven invoice-reminder workflow that sent one generic email regardless of which invoice was overdue.

`invoice-reminder-sheets`

Sheet-driven invoice reminder for freelancers, consultants, and small businesses. Reads an InvoiceLog Sheet, finds rows whose due_date has passed, and sends a personalized reminder email to each overdue client referencing their specific invoice number, amount, and days past due. Escalates tone across three stages — friendly → follow-up → final — and stamps each row to prevent duplicate chases.

Why this exists

The original invoice-reminder hub workflow reads a local CSV and then sends ONE generic email body ("This is a friendly reminder that your invoice is now 14 days old") regardless of which client is overdue or for how much. That's not a real reminder system — it's a placebo.

This variant fixes both gaps: - The data lives in a Sheet you edit on your phone, not a CSV on the server's filesystem. - The email body includes the actual invoice number, amount, due date, and days past due, addressed to the actual client by name. - The tone escalates: a 7-day-past-due reminder reads differently from a 60-day-past-due one. - A stamp on each row prevents re-chasing every day for the same invoice.

Setup

Credentials (Credentials view): - google-workspace — Google Workspace service-account JSON
Runtime environment (Runtime Environments view): - python — auto-created on every install
InvoiceLog Sheet (one-time): - Create a Sheet with a tab InvoiceLog and 10 columns: A invoice_no | B client_name | C client_email | D invoice_date E due_date | F amount | G currency | H status I last_reminder | J notes - Row 1 is the header. Data starts at row 2. - You maintain A–G and J. The workflow updates H and I. - Status flow: leave H blank or open when an invoice is sent → workflow sets it to reminded-1 after first chase, reminded-2 after second, reminded-3+ after subsequent → you set it to paid or written-off when the matter closes.
Edit workflow.yaml — replace the three placeholders: - <<INVOICE_LOG_SHEET_ID>> — spreadsheet ID from the Sheet's URL - <<YOUR_NAME_OR_BUSINESS>> — used in the email signature - <<OWNER_PUBLISHER>> — user name for the daily "what got sent" summary
Schedule once daily, 9:00 AM (or whenever you'd want to send chase emails).

Reminder cadence

Status when workflow sees row	Threshold to send	Sets status to	Tone
`open` (or blank)	days past due ≥ 7	`reminded-1`	friendly: "this is a friendly reminder…"
`reminded-1`	14 days since last reminder	`reminded-2`	follow-up: "I sent a reminder a couple weeks ago…"
`reminded-2`	14 days since last reminder	`reminded-3+`	final: "this is a final reminder, please remit within 7 days…"
`reminded-3+`	14 days since last reminder	stays `reminded-3+`	final (continues)
`paid`, `written-off`	—	—	ignored

Thresholds are constants at the top of the python script — adjust to your collection policy.

Pipeline

chase — runtimeenv (python). Reads InvoiceLog!A2:J, decides per row which reminder stage applies (if any), sends the corresponding personalized email, updates the row's status + last_reminder columns. Prints a summary.
notify-self — message. Pipes the summary to your owner user so you see, every morning, what got sent (or "No invoices need a reminder today").

Sample summary

INVOICE REMINDERS — Monday, May 11, 2026

Sent 3 reminder(s):
  [1st] INV-2026-044  Acme Corp           (9 days past due)
  [2nd] INV-2026-031  Beta Services       (28 days past due)
  [FINAL] INV-2026-018  Gamma Engineering  (62 days past due)

Customization

Thresholds — FIRST_AFTER_DAYS, ESCALATE_AFTER_DAYS at the top of the chase script. Aggressive: 5/10. Patient: 14/30. Default: 7/14.
Email wording — three body templates in the script (one per stage). Edit to match your voice; the placeholders for client name, invoice number, amount, and days past due all stay available.
CC your accountant on stage-3+ — add --cc [email protected] to the third stage's gog gmail send call.
Send a copy to yourself — add --bcc [email protected] to all sends.
Different currencies in one Sheet — already handled via column G; the email body uses the row's currency verbatim.
Don't escalate past stage-2 — change the third stage's status update to paused and have your accountant or attorney take over. The workflow will then skip those rows.

Companion artifacts

quote-followup (mech-eng workflow) — same pattern for outstanding quotes
shop-status-digest (mech-eng workflow) — could be extended to count overdue invoices in the morning digest

Verified

gog sheets get/update syntax, gog gmail send --to/--subject/--body flags, and the pipe-separated multi-cell update format all verified against the bundled gog v0.19.0 (2026-06-01); re-verify output shapes on first run. Status-stage state machine logic walked manually against worked examples.

Source

See workflow.yaml.