Any company needs at one point to get money from customers. That's when things gets messy for us developers, as we try to reconcile the complexity of the business with our software stack.
This 
list helps software engineers bootstrap billing & payments systems, and make sense of invoicing, pricing, accounting, marketplace, fraud and business intelligence.
A great introduction on all the various aspects of a billing system, from currency to invoices, including great illustrations on the logic of changing plans. All these topics are detailed in dedicated sections below.
Links to the *Billing and Cost Management* section which details the broad characteristics of billing for a cloud provider.
[Get rid of integers and floats for monetary values](https://xunroll.com/thread/1599113889093890049). Use decimals. Or face the risks of anomalous x100 charges.
In a Stanford class providing an overview of cloud computing, the software architecture of the platform is described as in the right diagram →
Billing is one of the transversal pillar of the ecosystem, where customers, products and business meets. The other pillar being Identity and Access Management (IAM) 👤.
This highlight the strategic importance of the domain, not only for cloud providers but virtually any business, especially those who are software-centric.
Huge and complete collection of pricing scheme, with their psychological effect and impact on revenue model.
A list of 15 different ways to sell products and services.
38 models for inspiration.
6 models of monetization relying on network effect.
A manifesto inspired by the DevOps movement in which pricing is no longer ossified, but is practiced as a responsive iteration process, and implemented as a flexible property of the system.
A collection of 1000+ pricing pages for inspiration.
From monthly subscription to commodity-like on-the-go consumption, there's plenty of scheme out there to structure your product's pricing. Including the good old shopping-cart funnel.
Real-time monetization infrastructure for AI products: meter usage, charge from prepaid balances, and ship a branded customer portal without writing frontend. Commercial SaaS.
“The most important reason I like this pricing model is that it heavily incentivizes both the customer and the service provider to act in everyone's best interest.” Also details issues with other pricing models.
The reason usage-based pricing makes even more sense for cloud services: to optimize ROI, keep all regular workload in traditional architecture and reserve cloud computing for elastic and experimental projects.
“The socially optimal operating point is unique, and can be sustained by a linear, usage-based tariff, which charges a fixed price per unit resource and unit time.” This paper justify usage-based pricing for cloud resources.
“The strategy of improving user service quality is discussed first, followed by the pricing strategy for cloud resources to maximize revenue.”
The starting point about quantization of usage.
Implementing usage-based pricing is tricky, and this algebra will help you organize temporal reasoning. Also see this [Stack Overflow question with clean schema](https://web.archive.org/web/20240413010618/https://stackoverflow.com/questions/12069082/allens-interval-algebra-operations-in-sql?rq=1).
Behind the quest of this developer to track its expenses, you get a glimpse on cloud billing difficulties. While not explicitly pointed out, pricing cloud resources is hard and the result of quantization, granularity and rounding, between space, time and currencies.
An example of really tricky burstable instances which accrues and limits its own amount of CPU usage credits.
Personal anecdote on the design of the pricing plan for AWS Simple Email Service.
Usage-based pricing is more optimal and more fair: it “allows a customer to start at a low cost, minimizing friction to getting started while still preserving the ability to monetize a customer over time”.
Before the cloud, there was another metered resource priced by its usage: electricity. Here is a detailed (and multi-lingual) taxonomy of its vocabulary from the International Electrotechnical Commission.
💸 Open-source metering & usage-based billing in Ruby. Lago SAS sells a hosted Cloud and Premium add-ons on top of the AGPL core.
🆓 Open-source, Stripe-native usage metering in TypeScript. Reconciles computed usage against Stripe invoices for “pre-invoice parity”, with exactly-once processing and real-time cost projections.
🆓 An open-source, fast (50k+ CPS) and scalable (load-balancer + replication included) real-time billing for ISPs and Telecom Operators, written in Go. Vendor-neutral, support-only commercial model.
The dynamic scheme for elastic resources.
“In low-touch SaaS, the most common way packages are presented are as different columns in a pricing grid, with each column corresponding to a plan, offered at a different price, with differential access to features or maximum allowable usage along some axis interesting to the business.”
🆓 Open-source project to manage pricing & packaging infrastructure. Lotus Inc. only sells managed hosting on top of the MIT core.
🆓 Open-source license key generation and verification tool in Go. Solo-maintainer project, no commercial offering.
Highly popular for SaaS businesses, subscription plans are easy to comprehend.
Beyond linear pricing, there is a place for additional platform fees and free-tiers in the pricing structure.
Uncommon pricing schemes.
Which numbers should you use? How high should it be? Should it be rounded? This guide has 42 tricks to help you choose the best price.
Pricing is an offensive tool to reinforce your product value and underscore the company core marketing message.
Explain how to articulate the pricing of SaaS businesses around the product strategy.
Explains why it is a sloppy analogy.
A couple of ways to re-license your product.
Theory and practical insight to help you choose the right pricing tactics.
“In insurance, the price is the product. (…) How do I change price to make shitload of money?” Or how to deliver results (optimal price for a customer) instead of delivering data (calculating a customer's risk, which had been the standard approach used by actuaries previously).
Used in surveys to determine the price for a new product or service. The results can be used to produce a demand chart and a revenue curve.
PSM is a market technique for determining consumer price preferences. Allows for drawing a revenue curve to estimate the price point delivering the maximum revenue.
“The most compelling argument against simply picking a price, though, is that it limits how much you can learn about your market.” Then the author setup vickrey auctions to discover price.
“To find the optimal price that provides maximum revenue for your product you will need to field-test several price points; you then reconstruct the revenue curve and find the peak.”
Some cases of price personalisation are prohibited in EU due to consumer protection and data protection rules.
Survey methods and price discovery techniques to find the right price point.
All GCP SKUs available as an API.
💸 An open-source UI and database to manage product metadata, written in PHP Symfony. Pimcore GmbH sells Enterprise Subscription, PaaS, and proprietary modules on top of the GPL/POCL core.
The central repository of all available services, products, variants, options and pricing available to the customer to purchase. Catalogs for cloud services are most of the time tailor-made, but there is some classic PDM solutions (Product Data Management, a.k.a. PIM for Product Information Management) out there that might fit the bill.
💸 Cloud cost estimates from Terraform code, surfaced as a breakdown in the terminal or as a diff in pull requests before resources are provisioned. Infracost Inc. sells a hosted dashboard (Infracost Cloud) on top of the Apache-2.0 CLI.
💸 A comparison matrix which use ECU (Amazon's vCPU) as a CPU power measure unit. Operated by Cloudorado as a commercial cloud-comparison product.
💸 Easy Amazon EC2 Instance Comparison. Operated by Vantage as a free lead-gen surface for its commercial FinOps platform.
Simulate a virtual invoice depending on the resource you plan to use.
“Comprehensive introduction to forecasting methods and to present enough information about each method for readers to be able to use them sensibly.”
Discusses how Uber apply data science and machine learning in their financial planning platforms.
Great introduction on how time series can be used to evaluate business problems.
🆓 Python library for time-series machine learning, governed by the Alan Turing Institute. See the [forecasting tutorial](https://github.com/alan-turing-institute/sktime/blob/master/examples/01_forecasting.ipynb) and the [differences between sktime and the Prophet project](https://news.ycombinator.com/item?id=24543861).
🆓 Python library for user-friendly forecasting and anomaly detection on time series, stewarded by Unit8 SA which only sells consulting around it (no paid library tier). Wraps a huge number of models, including [Prophet](https://facebook.github.io/prophet/). Great for experiments, but bear in mind that all the [models in Darts expects](https://news.ycombinator.com/item?id=37665435) that your data comes at a very regular interval, and make a lot of assumptions about their shape.
💸 Open-source tool to stay under budget by uncovering hidden costs, monitoring increases in spend, and making impactful changes based on custom recommendations. Tailwarden sells a hosted SaaS on top.
An example of consumption trend line for resource consumption.
“The biggest cost savings there are: 1. Turning things off that you're not using; 2. Then spot instances; 3. Then reserved instances.”
Help your customers predict their upcoming and future consumption based on their past usage.
This paper describes the pricing strategy model deployed at Airbnb.
A collection of papers on bidding and auctions.
Hinted by an [HN comment](https://news.ycombinator.com/item?id=19145391), in which yes, “‘Asking people what they'd pay for and how much rarely works.’ (…) Using a Vickrey auction, similar to Google's ad auction mechanism, can elicit a person's maximum willingness-to-pay.”
“Which comes first, the supply or the demand? Chicken or egg?”
A bit of vocabulary: “In a casino, the term *rake* refers to the commission that the house earns for operating a poker game. (…) While casinos use the term *rake*, a plethora of interesting word choices exist which all describe the same thing – keeping a little bit of the revenue for the company that is running the service.”
A marketplace connect supply with demand that lead to a financial transaction. If there is no payment involved, then it is an aggregator, or a hub. Not a marketplace.
Paper exploring the “mechanisms for the allocation of processor time and storage that are compatible both with programming practice and with market mechanisms.”
“How should the consumer modulate its demand to optimize its profits? (…) How should the provider and consumer negotiate the specific pricing structure they will employ?” Covers non-linear models, tiered pricing, elastic demand, consumer et provider strategies.
From AWS's original auction-based market (2009-2017) to provider-managed pricing across all major clouds today. Documents how transparent bidding was replaced by opaque algorithms.
“Amazon's spot price is unlikely to be set according to market supply and demand. Rather, price oscillates within a very narrow band most of the time, which is more likely to be an artifact of some pricing algorithm with predetermined reserve price.”
“We examine the economics of demand and supply in cloud computing. (…) These results explain why fixed prices currently prevail despite the seeming need for time-varying dynamics. Examining the actual CPU utilization provides a lens into the future. (…) demand fluctuations would be on par with the three classic industries where dynamic pricing is important (hotels, electricity, airlines) and dynamic prices would be essential for efficiency.”
“The key idea of our algorithms is to use pricing signal to regulate user demand. One may argue that such an algorithm gives poor service to the user as it pushes tasks out of the queue in order to maximize cloud broker's profit.”
“Pricing policy of spot resources should be carefully designed and the impact on both present and future should be considered.”
“Cloud providers possessing large quantities of spare capacity must either incentivize clients to purchase it or suffer losses. Amazon is the first cloud provider to address this challenge, by allowing clients to bid on spare capacity and by granting resources to bidders while their bids exceed a periodically changing spot price.”
“Google's prices are fixed, whereas AWS uses a market model”.
When you're big enough that [creating an internal secondary market](https://web.archive.org/web/20200101000000/https://medium.com/netflix-techblog/creating-your-own-ec2-spot-market-6dd001875f5) for instances makes economic sense.
This sub-section focus on bid/ask mechanism matching resource producer with consumers. Most of the time these are one-sided markets with the big platform trying to amortized under-utilized inventory.
“You always pay the spot market price, not your bid.” (source) - Simple explanation of the bidding mechanism.
“Look at the 3-month spot price history to estimate cost and to discover combinations of availability zone and instance type with extra capacity.” (source) - Users are seeking more transparency on the spot market.
A reading list distilling research papers from Turn Inc., Yahoo, and LinkedIn on RTB budget pacing techniques. Static resource: dated but still a useful entry point into the literature.
How to scale to 5M bid request/s, 2ms Max Response Time.
🆓 Apache-2.0 OpenRTB 2.0-compliant bidder and Demand Side Platform (DSP). Largely dormant since late 2022, but the only OSS DSP reference in this niche.
Targeted online advertisements marketplaces have a lot in common with traditional cloud marketplace. Some good inspiration there, from concepts to tech.
A general introduction to history and vocabulary of accounting.
Describes how to view accounting in the form of graphs in which money flows, then how these movements are materialized in the financial statements of a small company.
Same premise as above, but way more detailed and complete, as it adds reporting and implementation details.
An interactive form to play with accounting concepts.
The core concept of accounting is double-entry. It is the most critical part to grasp in order to properly design any robust system that tracks money.
Focus on the daily operations of recording and maintaining the transactions of a business.
“Reconciliation is a business process which arises almost entirely because of a lack of structured data in the pipelines that convey money between businesses”. There are some hack to streamline the process, like adding an arbitrary discount to produce unique trailing decimals, or setup a couple of virtual bank accounts as proxy.
Extensive list of open-source personal finance projects that might be great to look into for inspiration on double-entry accounting and bookkeeping.
A complete tutorial on personal finance tracking with GnuCash.
🆓 Free desktop book-keeping software for small-businesses and freelancers, with no paid edition.
🆓 YAML accounting and JSON tax forms, solo-maintained.
🆓 Open source accounting system that aims to make the recording of double entry bookkeeping transactions programmable.
💸 MIT-licensed programmable double-entry ledger with the Numscript DSL, multi-currency, REST API, and Docker deployment usable standalone. Formance sells Enterprise add-ons (Wallets, Flows, Reconciliation, pre-built connectors, SSO, RBAC, audit logs) on top, but the core ledger is fully functional in OSS.
Everything you need to know about the daily practice of keeping your accounting data clean and tidy.
Design decisions behind a billing and accounting system. Key takeaway: some companies still pays by checks; do not use floats; complex customer workflows; date and time issues; mutable data.
Explain the basic data model of a double-entry accounting system relying on Google Spanner for internal use at Square.
🆓 A distributed financial accounting database to ensure that the money either moves, or doesn't move, that it doesn't get lost somewhere in between. All features are in the Apache-2.0 OSS repo; TigerBeetle Inc. sells managed hosting and support, not gated features. It has been [tested on Jepsen](https://jepsen.io/analyses/tigerbeetle-0.16.11), which tested its strong serializability.
🆓 Core functionality of a double entry accounting system for Django, single-maintainer MIT library.
🆓 A 'managed account' is an allocation of money that can be debited and credited. Community-maintained django-oscar extension.
“Triple‐entry accounting is a new and a more efficient way to address fundamental trust and transparency issues that plague current accounting systems. Triple‐entry accounting with Blockchain, when properly implemented, can fundamentally improve accounting.”
Now that you're somewhat familiar with the concepts and practice of accounting, here are some resources to help you implement that knowledge into software systems.
An excellent resource for implementing multi-currency accounting systems.
Global companies needs to know how to juggle between local currencies.
Helps you learn how to analyse and monitor your company's financial performance.
“Malone created a new accounting metric, something he called ‘earnings before interest, depreciation, and taxes’, or EBITDA.” This is how a cable company CEO made sense of cash flow, like real-estate business did. The article starts with this example and describes other cash flow games for SaaS models.
Allows you to fully understand how to use financial data to make better decisions for your business.
A framework for tech finance and business leadership teams to share the same language and processes of cloud operations and management.
Advanced abstract algebra applied to the analysis of accounting systems.
Once you've got your accounts in order, you can start extracting insights and metrics from your financial data.
When contracts, invoicing and payments are not working together, you end up alienating your big enterprise customers. See the associated HN comments [on bulk license purchase](https://news.ycombinator.com/item?id=27053246).
“The concept of Entitlements encapsulates the feature access settings under various product variants (aka Pricing Plans or Packages), bridging the gap between how a product is sold and how it behaves for a variant. In essence, entitlements are a set of permissions defining what a customer (paying or non-paying) can do with your software application.”
Explains the differences between various types of discounts and usage commitments in GCP.
“Implementing price reductions ranging from 9–70% for large purchases, we found remarkably little impact on revenue, either positively or negatively.” If discounts are a placebo and are still widely used in the industry, maybe they are a marketing hack to lure big customers?
All the invoicing terms & conditions are materialzed by the contract signed between the end-user and the service provider. That's the source from where we derives all the rules of the billing cycle.
Backblaze post-mortem on raising prices on their main offer. They wanted to create an extension program based on credit system. This became a full-time job for a handful of their most senior engineers, and resulted in a six month project.
The reason you have to add an time limit on credits: unused ones accounts as liabilities on our balance sheet.
A cautionary tale on how promo codes can be exploited to get unlimited free rides.
The next level of fraud: “an online collective exploited a loophole on its platform to ‘steal’ tens of millions of yuan worth of discount vouchers”.
European directive on the application of VAT when vouchers are involved.
Point the negative consequences of users encountering a blank coupon field without having a coupon. See the update at the end of the article with research backing up this anecdote.
A list of test cases for developers to test their tax code against.
🆓 Centralize applicable VAT rates on foreign online services, for each country of residence (including territorial exceptions).
List of countries requiring application of taxes on foreign provided online services.
A multi-states US initiative to automate and standadize sales tax accounting and collection.
“If you think you can just setup a simple Stripe integration and move on, like us, you'd be sadly mistaken.”
European Union reference on the common system of VAT.
Answer: a provision in which a business transfer the responsibility of VAT handling to the customer.
[Invoiced billing](https://cloud.google.com/billing/docs/how-to/invoiced-billing) is a B2B-friendly payment happening after the service is consumed and an invoice issued. It seems to be a pain to setup on GCP but I suspect is a consequence of trying to reduce (costly) fraud.
The invoice materialize a consumed service or purchased product, waiting to be settled by a payment transaction.
The information required on a EU invoice is detailed by Article 226, Section 4 (Content of invoices) of Council Directive 2006/112/EC on the common system of VAT.
Here is a great way to rely on GCP's HSM to digitally sign documents and provide an immutable audit-trail. Might be applied to invoices as well as contract agreements.
Go beyond the solution above, and timestamp immutable document directly on Bitcoin's blockchain.
Because an invoice is immutable, the only way to fully or partially cancel it is to produce a credit note.
Once issued, an invoice must be immutable.
🆓 Offline-first desktop app to create, manage and export invoices and quotes to PDF, with all data kept in a local database you own.
🆓 A self-hosted open-source application for managing your invoices, clients and payments. Community project, no paid edition.
🆓 Zero-maintenance FOSS CLI tool for generating beautiful invoices for services and expenses.
🆓 Python library to generate simple invoices.
🆓 Fast Node.js library to generate PDF invoices with PDFKit, no headless browser required.
🆓 For generating and displaying invoices (ideal for commercial Rails apps). It allows for flexible business logic; provides tools for tax handling, commission calculation etc.
🆓 Deep neural network to extract intelligent information from invoice documents.
European Union introduced a "standard" in XML format, which comes with a set of security vulnerabilities.
European standard on electronic invoice.
🆓 Python library to support the e-invoicing standard for France and Germany.
Most invoicing software can read and write UBL documents (XML) for data transfer.
💸 JSON Schema, Open Source Go library, global tax database, with conversion tools, all in one. Invopop sells a managed e-invoicing SaaS implementation on top of the open spec.
A benchmark of top payment providers, their pricing and models.
RDBMS were build for banks around transactions to solve that specific issue. Then NoSQL came forcing us to carefully implement systems to avoid double spending.
Or why you should be prepared for and work around gateway provider's outages.
The importance of payment ops architecture.
European rules on applicable fees for late payments.
The root cause? People wearing a lot of wool in low humidity air, generating a lot of static.
Dropbox's experience trying to account for an unreliable payment provider.
Under a constant stream of user complaints about payments, WordPress created a dedicated subdomains to help customers understand unexpected transactions. The trick was to add this URL directly in the bank statement.
💸 Open-source backend for payment processing. Juspay sells Hyperswitch Cloud and a self-host Enterprise edition; the OSS is functionally complete with 90+ connectors, vault, routing, 3DS, and fraud orchestration.
💸 Open-source monetization platform to sell SaaS and digital products. Polar Software Inc. runs the hosted polar.sh service as the merchant of record, handling billing, sales tax and VAT remittance for a cut of each transaction; the self-hostable OSS ships the full stack (checkout, subscriptions, usage metering, license keys) on top of your own Stripe account.
🆓 Suite of Apache-2.0 libraries for financial technology, including [`moov-io/ach`](https://github.com/moov-io/ach), [`iso8583`](https://github.com/moov-io/iso8583), and [`watchman`](https://github.com/moov-io/watchman). No paid product on top.
🆓 Linux Foundation project hosting open-source projects for financial services.
When a Netflix data engineer revisit receipts.
“CVS is a drugstore much like other drugstores, with one important difference: The receipts are very long.”
A receipt materialize the payment transaction.
Some credit and debit card companies have "updating service" that allows new account numbers and expiry dates to be shared with merchants. Visa's implementation is called [VAU](https://developer.visa.com/capabilities/vau) and Mastercard's is [ABU](https://developer.mastercard.com/product/automatic-billing-updater-abu/).
[Payment Services Directive](https://en.wikipedia.org/wiki/Payment_Services_Directive) 2, explained.
A system checking the matching of customer's billing addresses with the one associated with the credit card.
The most popular payment device.
Collection of miscellaneous notes primarily focused on the common cases of routable accounts, i.e. checking and savings.
🆓 Free and public IBAN validation and calculation webservice.
Swift / BIC codes for personal use only.
🆓 Static JSON dataset of SWIFT/BIC codes for banks worldwide, scraped from the site above. Last refreshed in 2019 but still the largest free reference; SWIFT codes change slowly so the data remains broadly usable.
EU standard for QR codes used to transfer money between bank accounts via SEPA.
The old-fashioned way of payment: by the way of banks.
“In this article, we will learn about India's Unified Payments Interface. A four-year-old payment scheme that has been accounting for 40-45% of digital payments across India.”
A huge collection of everything that went wrong, and still is, with payment APIs from the past 2 decades. Any issue exposed in this article that gets unaddressed will end up as stolen money.
In which we learn that “once turnover hit a certain level, Paypal automatically put the business on a 21 to 60 day rolling reserve, meaning that up to 30 per cent of a company's revenue could be locked up for up to two months.”
“Idempotency prevents race conditions. Idempotency dictates that multiple identical requests from the same client do not result in a different final state.”
Describes a classic payment workflow, then how machine learning can replace hard-coded business rules and fine-tune the payment failures/retries loop to increase the success rates of charges.
The usual money transfer services.
Discusses a method to detect fraudulent activity (launching DDoS attacks, Bitcoin mining, …) by using non-intrusive, privacy-friendly data: billing data.
Section dedicated to fraud management related to user accounts, from our sister repository.
In this talk by Uber Eats, we learn from the biggest payment processor that “growing businesses with declining loss rates is extremely rare in the industry”. Also, fraud can takes several forms: chargebacks on non-perishable goods, promo abuse, refunds…
KYC is nuanced and fuzzy, because it is a stochastic process to reduce risk.
Papers sourced from several conferences on all sort of fraud: credit card, payment transactions, loans, customs inspections, money laundering networks, and more.
🆓 Open-source real-time transaction monitoring software for fraud and money laundering detection, governed by the Tazama Linux Foundation project. This is just an engine to define rules, weight them, and apply them to transactions. There is nothing specific to payments or financial transactions.
🆓 Concrete AML rule implementations from the Mojaloop Foundation: transaction mirroring (90-100% amount-match window), multi-tier payee-graph traversal for layering detection, account-dormancy reactivation, large-transaction-payer, new-payee-transfer. Repo is archived but the rules are static reference material rarely seen elsewhere in OSS.
There's monetary incentives to exploit your business. Be prepared to fight hordes of fraudsters and shady users.
A practical handbook on how to identify patterns in transactions.
Describe a fraud technique known as "card testing", in which massive batch of stolen cards are checked for their validity against your API.
Suggestions involved either [warning signals](https://www.candyjapan.com/behind-the-scenes/fraudulent-transaction-warning-signs) for trying to guess which orders might be fraud, or countermeasures to try to make things harder for the fraudsters.
Another tiny collection of features we can feed to a ML system to detect fraud. Comments on HN also unearthed [more qualifying signals](https://news.ycombinator.com/item?id=6376350) and [derived geodata on the transaction](https://news.ycombinator.com/item?id=6376221).
Tutorial on how to rely on anomaly detection to implement suspicious card transactions.
An example of a platform's network effect, which allows to predict the likelihood of winning a dispute.
To prevent abuses, service provider must strengthen both credit card verification and the account creation process.
The majority of fraud is exploiting the most common popular payment device: credit cards.
Or why relying too much on fraud automation might lead to disgruntled users.
Aggressively shutting down user servers is good from a business point of view to prevent fraudster abusing free resources, until it's not.
How to use statistical methods to classify applicants into categories to reduce risks. Lots of inspiration and research papers there to improve general scoring.
Synthetic score based on a collection of signals are often the best proxy of user's trustworthiness. Customer support most of the time rely on them to take action when these actions are not triggered automatically.
Digit distribution can be a signal of accounting fraud.
In the same spirit as above, this paper show that frequency of reported round numbers in election is a signal of man-made anomalies. Might be applicable in some fraud-fighting area.
“A loss function used in robust regression, that is less sensitive to outliers in data than the squared error loss.”
Simple way to detect outliers.
Standard manual accounting trick employed when isolating an error in a double ledger.
Best tools to automate fraud detection.
A new kind of fraud, in which apps silently keep charging users after the end of the trial period.
A billing team responsible for collecting payment is prey to this kind of fraud, in which the CEO is impersonated to commend exceptional payment transactions.
Skip the first 90% of this presentation by an AWS VP (which is about general system reliability). The last four slides are a good summary of what billing cloud services entails, especially the use of soft quotas to limit fraud.
Most of telephony frauds gravitates around billing and the metering of micro-transactions. This paper feature a taxonomy (on page 6) differentiating the root causes, vulnerabilities, exploitation techniques, and the way fraudsters can benefits from them.
Guide and recommendation on how to make [auto-renewable subscriptions](https://developer.apple.com/app-store/subscriptions/) user-friendly.
Focus first on other things in the cart, like easing anxiety and second-guessing by adding reassurance (trust marks, testimonials) near the credit card and completion steps, as well as some guarantee language that you may have used earlier in the product exploration process.
Failed attempt to move the billing experience by from backend to frontend because of security.
A collection of pricing pages from various SaaS companies, to get inspiration on how to present your offers.
Users gets easily angry when it comes to money. UX and UI might helps a lot to reduce frustration.
As stakeholder of the billing pipeline, you sat on all the critical data to measure and report on the health of the business.
A great source of inspiration to get better visibility in your operations.
The 2 critical metrics being Customer Acquisition Cost (CAC) and Customer Lifetime Value (CLV).
Discuss the relationship between investments, profit and growth, and how it influence decisions on pricing, free trials and plan structure.
Metrics produced above have a greater reach, as they're used as important signals to validate product-market fit.
Simple yet effective interactive profitability calculator for startups.
Great breakdown of Visa business models and metrics.
A complete tour of the financials of a startup, which gives you extra-context on how the metrics you produce fit into the larger picture.
Definition and collection of Key Performance Indicators (KPIs) worth monitoring.
“On the surface, churn rate may seem like a natural proxy for changes in customer lifetimes. Let's dig into why that is not true.” Churn rate is not a meaningful metric to compute CLV: during the customer lifetime, the churn probability is not constant. Most of the time because of your free trial and vouchers. This article illustrate the influence of the distribution used to model the probability of a customer quitting.
A seminal paper, with a stronger approach compared to the one above: [the exponential distributions is replaced by a geometric model](https://news.ycombinator.com/item?id=24833319), which is better suited to discrete time intervals like monthly contracts, the former being more appropriate to continuous time process.
Illustrates how retention can be better modelled using a survival function like [Kaplan–Meier survival curves](https://two-wrongs.com/bootstrapping-kaplan-meier-confidence-intervals.html).
A refined model of CLV, used to segment users based on Recency, Frequency and Monetary value.
“How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
🆓 A full-featured Python package to analyze your users based on their "alive" and "dead" states. Apache-2.0 library stewarded by PyMC Labs, which only sells consulting services around it (no paid library tier).
How much value do you produce per customer? The Customer Lifetime Value (CLV, or LTV for Life-Time Value) quantify that. Understanding and acting on it is the most important part of your business's sales efforts.
“Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
You don't need data scientists. “For ETL, hire data engineers. For reporting, hire BI analysts. The end.”
“Data science is best viewed as a form of company culture, rather than a set of technologies. However, many firms will try to create that company culture by acquiring data-science technology, rather than working on their culture.”
Because of precision: floats and doubles cannot accurately represent the base 10 multiples that we use for money.
“This is precisely the problem we have when trying to represent 10^-1, or 0.1 in binary. There is not an exact binary representation of 0.1 or 0.01.”
Floats were suspicious even before the first general-purpose computer (EDVAC) was built: “Von Neumann wasn't entirely sold on why we might need floating-point numbers. He was quite vocal in his critique of floating-point numbers.” The author of this article complement this critique by illustrating the issue of precision and rounding.
A collection of cases in which uncontrolled and untested spreadsheet models led to lost revenue, mispricing, poor decision making, fraud and systemic financial failure.
To industrialize data production and consumption, your need data engineers to clean up, persist and consolidate data. Only after you get these data foundations you might think of onboarding data scientists.
A blog collecting and spreading ideas on how to use Python more effectively in the business setting.
🆓 Connect and query your data sources, build dashboards to visualize data and share them with your company. Owned by Databricks but the hosted SaaS shut down in 2021, so the project is now community-maintained under the Databricks org with no paid Redash product.
🆓 Enterprise-ready business intelligence web application, governed by the Apache Software Foundation.
🆓 Open source convention-over-configuration product for the whole data lifecycle, all the way from loading data to analyzing it. Meltano only sells managed Cloud hosting and support SLA on top of the OSS core.
Software to build visualizations, dashboards, SQL queries and drill down into data.
All of them have been abandoned and constitute prior art. This means there is nothing to prevent anybody to implement or commercialize these concepts.
A bunch of resources to keep track of the current status and progress of all companies operating in the domain.
The source of all new features added to the billing perimeter.
A feature matrix of the different scheme and their average dicounts.
Latest changes of GCP billing features.
From the unofficial Google Cloud Platform newsletter.
A wrap-up of recent GCP pricing features.
GCP's billing subsidiary.
All the latest billing updates on DO.
AWS sacrificed the simplicity of subscription pricing for S3 and went instead with a safe cost-following strategy because they had no clue how the users will use their service.
Invoicing of random fees with coded amounts were used as a hidden signal to bypass legal obligations. Maybe that's why you need a flexible billing system after all.
The IBM 1401 mainframe (1959) optionally supported pounds/shillings/pence (£sd) currency arithmetics in hardware.
Starting at page #445, the "10.5 Billing Equipment and Systems" section describe the history and technical evolutions of Bell's phone calls metering and pricing.
Accounting paintings were a significant genre in Dutch art.
A way to optimize pricing using a physical model made in plaster of Paris, from 1914.
A site mockup of an tax avoidance product for small businesses.
Billing is not funny.
The header image is based on a modified photo by Denny Müller.
[1]: Sapiens: A Brief History of Humankind (Harper, 2015). [↑]
