Recurring Invoice & Retainer Biller

$19.00

a solo or small services business running a book of recurring clients who keeps having to reconstruct, from memory, who owes what this month.

Local-firstNo telemetry — nothing phones homeNo lock-inNo migration

Keep one list of retainer clients and it tells you exactly who’s due this billing month across monthly, quarterly, and annual cadences, prorates anyone who started mid-month, numbers the invoices, and shows you who still hasn’t paid.

$19 a month, flat, for the whole book. No per-client charge and no contract. Cancel any day and the invoice files you already generated stay on your disk.

The monthly ritual of remembering who owes you

On the first of the month you sit down and try to reconstruct your own book of business. Who’s on a monthly retainer, who’s quarterly, whose annual renewal lands this month, who signed mid-month and only owes part of it.

Then you draft each invoice by hand and, weeks later, try to recall who actually paid. It’s twenty minutes of clerical work that goes wrong in expensive directions: a retainer you forgot to bill, or one you billed twice.

One client list in, this period’s invoices out

  1. Keep a single CSV: client, amount, cadence, start date, description, status. Cadence is monthly, quarterly, or annual. Status is active or paused.
  2. It works out who’s genuinely due in the period. Monthly bills every month, quarterly every third month from the start date, annual only in the anniversary month. A client whose start date hasn’t arrived yet gets skipped.
  3. It builds the register with sequential, period-scoped numbers like INV-2026-07-0001, prorating any client whose first period began partway through the month.

What it produces

  • INVOICES.md and invoices.csv: this period’s register, numbered and ready to send from your own system.
  • First-period proration by days remaining over days in the month, so a client who signed on the 20th is billed for eleven days, not a full month they didn’t get.
  • AGING.md: hand it a payments log and it compares paid against billed, then lists every invoice that’s unpaid or short.
  • Paused clients stay in the file and simply don’t bill, so you never delete and re-add someone who’s on hold.
  • billing.json for anything downstream.

Who it’s for, and who it isn’t

Built for a solo or small services business running anywhere from a handful to a few dozen retainer clients on set amounts and a rhythm. Bookkeepers, agencies, fractional operators, anyone with a recurring book.

Not for you if you want invoices emailed and card payments collected automatically. This drafts the register and the aging view. Sending and taking payment stay in whatever tool you already use.

What it replaces, and what those do better

QuickBooks recurring invoices, or a spreadsheet you rebuild monthly. QuickBooks is better at the last mile: it emails the invoice, takes the card, and posts the payment against your books without you touching it.

What it also does is keep your entire client list on their servers and price accordingly. This holds the list on your machine and answers the one thing that actually eats your morning, who’s due and who hasn’t paid, for a flat fee. Pair it with your existing sender and both ends are covered.

Your data, and where it stays

Your client list, the amounts, the payment history, all of it reads from disk and writes back to disk at 0600 permissions with no network call. Who your clients are and what you charge each of them is the private core of a services business, and it doesn’t leave the machine to get billed.

$19 a month, and your first run

Set the client CSV, the output folder, the period, and your business name in a .env, then run. The first register takes a few minutes to check against what you expected. After that, the first of every month is one command.

Flat monthly, cancel any day, and the invoice files stay on your disk regardless.

Security and privacy

Handles client billing data (recurring amounts, billing history, payment status). Security is designed in.

Principles
Local-first. CLIENTS_CSV/PAYMENTS_CSV are read from disk and never transmitted anywhere; nothing in this tool touches the network. Nothing is uploaded, no telemetry, no cloud dependency.
Non-destructive. Source CSVs are only read, never modified or deleted.
Least privilege. Reads CLIENTS_CSV and (optionally) PAYMENTS_CSV, writes only under OUTPUT_FOLDER.

Protections implemented (v0.1.0)
Path-traversal defense — every output filename is sanitized (safeSegment) and every write is checked with assertWithinRoot(), so the billing report can’t be written outside OUTPUT_FOLDER.
Fail-fast config validation — clear errors for missing/invalid CLIENTS_CSV/OUTPUT_FOLDER/PERIOD before any file is touched.
Restrictive permissions — the generated report (INVOICES.md, invoices.csv, AGING.md, billing.json) is written 0600.
Defensive parsing — the CSV parser and currency parser never throw on malformed input; a client row with a missing/invalid cadence, status, or start_date is skipped (and counted) rather than crashing the run.
Secrets discipline.env and generated Billing/ output are git-ignored; no secrets or client data in the repo.

Distribution / AV trust

Known limitations / roadmap
monthly cadence is unconditionally “due” in isDueInPeriod; the pipeline separately guards against invoicing a period before the client’s start_date, but a manually-set PERIOD far in the future will still generate a monthly invoice for it — review PERIOD before running.
– Proration only covers the client’s *first* period (the one containing start_date); mid-contract cadence changes, price changes, or cancellations mid-period are not modeled.
– Aging is period-scoped: a payment must be tagged with the same client + period as the invoice it’s paying off. Payments logged against the wrong period will not net out correctly.
– No partial-payment carryover across periods — an underpayment in one period does not automatically roll into the next period’s invoice.

Reporting
Report suspected vulnerabilities privately to the maintainer before public disclosure.

Frequently asked questions about Recurring Invoice & Retainer Biller

What does the recurring invoice & retainer biller software do each month?

The Recurring Invoice & Retainer Biller reads one list of your repeat clients and generates the current period’s invoices from it, so you stop re-keying the same billing every month. You keep a list of recurring clients with their amounts and cadence, run the tool for the period, and get a set of branded invoices plus an accounts-receivable aging report that shows what is still outstanding. It handles both flat monthly retainers and fixed-fee work in the same pass.

The reader who wants this is a service firm on monthly retainers. The design and marketing shops, the bookkeepers, and the consultants who bill the same clients the same amounts every month and lose an afternoon copying last month’s invoices into this month. The recurring invoice & retainer biller software exists to take that afternoon back. You define the recurring list once, and each period becomes a single run rather than a stack of manual edits.

Retainers get their own handling because they behave differently from one-off invoices. A retainer is the same amount on the same day every month, and the biller treats it that way, generating it automatically as part of the period run instead of asking you to remember it. Flat-fee engagements slot in beside the retainers on the same list, so a firm that mixes ongoing retainers with fixed-scope projects bills both in one action rather than two.

The aging view is the second half of the value. Generating invoices is only useful if you can also see who has not paid. After a run, the tool shows outstanding balances by client and by age, so the invoice that went out sixty days ago and never came back is visible instead of forgotten. For a small firm, that outstanding view is often the difference between chasing a late payment and quietly writing it off.

Those invoices are also records the IRS expects a business to keep. Payments you receive for services can land on information returns, and the IRS explains in its guidance on Form 1099-K that card and third-party-network payments for goods or services get reported back to you. Having a clean, generated invoice behind every payment makes reconciling those year-end forms far less of a scramble, because the billing record and the reported total line up.

The branded part matters more than it sounds. An invoice that carries your name, your layout, and a consistent number is the invoice a client pays without questions, because it looks like the ones before it. The recurring invoice & retainer biller software applies that same branding to every client in the list, so a firm sending a dozen invoices a month is not rebuilding the look of each one. Consistency in how you bill is part of how you get paid on time.

Everything runs from your own list on your own machine, so client billing details are not parked in yet another hosted account. You get the period’s invoices, an aging report you can act on, and a record you can keep. You can see how the monthly run works on the product page, and browse the rest of the tools built for small operators on the small-business operators page. It does the repeat billing and the follow-up view, and nothing you do not need.

How does the biller help me keep the invoice records the IRS expects?

Every invoice you send is a supporting document behind the income you report, and the IRS expects a business to keep those documents organized and available. Its guidance on how long you should keep records sets the minimum periods, generally three years and longer in some cases, and it asks that the records be kept in an orderly way you can produce on request. A pile of one-off invoices re-typed each month is not that orderly record. A consistent, generated set is.

The Recurring Invoice & Retainer Biller helps because it produces each period’s invoices from the same list in the same format every time. That sameness is what makes the record trustworthy. When every invoice for a client follows the same layout and numbering, reconstructing a year of billing is a matter of reading down a list rather than hunting through a folder of documents that each look a little different because they were edited by hand.

The aging report adds a second layer to that record. It does not only show what you billed, it shows what came back and what is still open. For a firm that gets asked to explain its receivables, whether by an accountant at year end or a lender reviewing the books, an outstanding-by-age view produced straight from the billing run is far more credible than a memory of who owes what.

Keeping the record clean also pays off when the year-end forms arrive. Payments through cards and platforms get reported to you, and matching those totals to your own billing is where a lot of small firms lose an evening. Because the biller keeps a consistent invoice behind every recurring charge, the reconciliation is a comparison rather than an archaeology dig, and the numbers you report rest on documents you can actually show.

The recurring invoice & retainer biller software keeps all of this on your own machine, from your own client list. The records are yours, held where your books are, not scattered across a hosted billing service you would have to export from to answer a simple question. Orderly, reachable, and in one place is exactly the posture the retention guidance is asking for.

There is a further payoff at tax time, when a preparer or an accountant asks to see the year’s invoicing. A folder of hand-edited documents forces them to check each one, while a set generated from a single list reads as one coherent record they can trust at a glance. The recurring invoice & retainer biller software produces exactly that kind of set, which shortens the review and lowers the odds of a question you cannot answer quickly. For a small firm, a preparer who can move through your billing records fast is a preparer whose bill is smaller, so the consistency pays for itself twice.

None of this turns billing into bookkeeping, and the tool does not pretend to be a general ledger. What it does is make the billing side of your records consistent and easy to keep. You can read more about the invoice and aging output on the product page, and see the other tools built for small operators on the small-business operators page. Clean records start with invoices that look the same every month.

Where does my client billing data live, and is it kept private?

Your client list and the invoices you generate stay on your own machine. The Recurring Invoice & Retainer Biller works from a list you keep, and it produces the period’s invoices and the aging report locally, so the names, amounts, and payment histories of your clients are not sitting in a hosted billing account you have to trust. For a service firm, that billing data is some of the most sensitive material it holds, and keeping it local is the plainest way to protect it.

Billing records are exactly the kind of personal and financial information the Federal Trade Commission has in mind in its guide on protecting personal information. The guide tells businesses to hold only the data they need, to lock down what they keep, and to be deliberate about where it lives. A biller that runs from your own list, rather than uploading your whole client roster to a cloud service, keeps that footprint small and under your control.

There is nothing to log into and nothing syncing your receivables to an outside server as a condition of running the tool. That means fewer places your client data could be exposed and fewer accounts to secure. A small firm does not need another vendor holding its book of business. It needs the billing done and the records kept, without widening the circle of who touches that information.

Keeping the data local also means you are not depending on someone else’s service being up to reach your own invoices. Run the tool when you need the period’s billing, keep the output in your own folders, and the records are there whether or not any outside platform is. For an owner who has been burned by a subscription tool going dark, that independence is part of the value.

The recurring invoice & retainer biller software does not ask you to change how you already protect your machine. Your existing disk security and account protections keep doing their work. The tool simply avoids adding a new cloud copy of your client list to the pile, which is the simplest way to keep private information private.

It is worth being plain about the trade-off. Keeping billing local means the records live on your machine, so backing that machine up becomes your responsibility rather than a cloud provider’s. That is a fair price for keeping your client roster off a hosted service, and it is a familiar one for any owner who already keeps local books. The recurring invoice & retainer biller software fits that habit rather than fighting it, sitting beside the files you already back up instead of pulling your data into somewhere new. What you get in return is a client list that is not sitting in a third party’s database waiting to be part of someone else’s breach report, which for most service firms is the better end of the bargain.

This is not a claim that a local tool removes every risk a business faces. It is a claim that the tool does not create new exposure to do its job. You can read more about how the local run works on the product page, and see the wider lineup for small operators on the small-business operators page. Your billing data stays yours, on your own machine.

How is this different from QuickBooks Online or FreshBooks for repeat billing?

The full accounting suites can do recurring billing, but you have to buy and run the whole suite to get it, and in some cases true auto-charge recurring billing only shows up on the higher tiers. For a firm whose actual problem is re-keying the same monthly retainers, that is a lot of software and monthly cost for one job. The Recurring Invoice & Retainer Biller does that single job at a flat nineteen dollars a month, without asking you to move your books.

The difference is scope on purpose. QuickBooks Online and FreshBooks want to be your ledger, your expense tracker, and your reporting tool as well as your biller. This tool wants to generate the period’s recurring invoices and show you the aging, and stop there. A service firm that already has its books somewhere it likes does not need to switch accounting platforms just to stop copying invoices by hand every month.

Running the billing locally also keeps your client roster out of one more cloud account. That fits the Federal Trade Commission’s Safeguards Rule, which requires businesses that qualify as financial institutions to keep a written program of administrative, technical, and physical protections for customer information. Even if you are not covered, the spirit of the Safeguards Rule is to hold customer financial data deliberately, and a local biller keeps that data on your machine instead of a hosted platform.

Cost is the other honest difference. The suites price by tier and by feature, and the recurring-billing piece you actually want can sit behind an upgrade. A flat monthly fee for a focused biller is easy to reason about, and it does not climb every time you add a client or want a feature the plan gates. For an owner watching software costs, that predictability is part of the point.

The recurring invoice & retainer biller software is not trying to replace your accountant or your ledger. It is trying to remove the monthly re-keying and the receivables blind spot for firms that bill the same clients on repeat. If you need full accounting, keep it. If you only need the repeat billing handled, this is the narrower, cheaper tool for it.

None of this is a knock on the big suites when a firm genuinely needs full accounting. If you are running payroll, tracking inventory, and filing sales tax, a real ledger earns its cost. The point is that plenty of service firms are not doing any of that. They bill the same retainers every month and want that one job done cheaply and cleanly. The recurring invoice & retainer biller software is aimed squarely at that firm, the one paying suite prices for a single feature it actually uses. Paying a flat, small monthly fee for exactly the billing you do, and keeping your existing books wherever they already are, is the trade this tool is built to offer.

You can weigh the trade-off for your own firm on the product page, and see how the biller sits beside the other tools built for small operators on the small-business operators page. The short version is that you pay for the billing job you have, not for an accounting platform you do not want to switch to.

Can it show me an aging view of what clients still owe?

Yes. Every run of the Recurring Invoice & Retainer Biller produces an accounts-receivable aging view alongside the fresh invoices, so you see not just what you billed this period but what is still outstanding and how old it is. Generating invoices is only half the job. Knowing which of them came back is the half that protects your cash, and the aging report is built into the same run rather than being a separate report you have to assemble.

The aging view sorts outstanding balances by client and by age, so the account that has been open sixty or ninety days stands out from the one that just went out. For a small firm, that visibility is often the thing standing between a polite reminder and a written-off invoice. You cannot chase what you cannot see, and a receivables list that updates every time you bill keeps the slow-payers in view.

That outstanding record is also part of the orderly books the IRS expects a business to keep. The guidance on Form 1099-K is a reminder that the payments you actually receive for services get reported back to you, and being able to line up what you billed against what came in makes the year-end matching far cleaner. An aging report produced from the billing run gives you the billed side of that comparison in one place.

The report is generated locally from your own client list, so the receivables picture is yours to keep and act on without exporting it out of a hosted service first. Run the biller for the period and the aging view comes with it, updated for what has and has not been paid, ready to guide who you follow up with next.

For a firm on monthly retainers, the recurring invoice & retainer biller software turns receivables from a nagging worry into a list. Instead of a vague sense that a couple of clients are behind, you get names, amounts, and ages you can work down. That clarity is often worth more than the time saved on generating the invoices in the first place.

The aging view also changes the tone of your follow-ups, which matters more than it seems. When you can see precisely how old a balance is, your reminder can be specific and calm rather than vague and apologetic. A client is far likelier to pay a clear note that references a sixty-day-old invoice number than a hesitant message that sounds unsure whether anything is owed at all. The recurring invoice & retainer biller software gives you that certainty by keeping the receivables current every time you bill, so the follow-up you send rests on a number you can stand behind. Over a year, that confidence is often what pulls the slow payers back in.

You still make the call on how to handle each late account, and the tool leaves collections judgment to you. What it does is make sure nothing slips out of view. You can see how the aging output looks on the product page, and browse the rest of the tools for small operators on the small-business operators page. Bill the period, then see exactly who still owes.

Attributes Value
Deployment

Cloud

Platform

Web

License Type

Subscription

Billing Period

Monthly

Target Customer

Small Business & Retail

Free Trial

Yes

Reviews

Be the first to review “Recurring Invoice & Retainer Biller”

Your email address will not be published. Required fields are marked *