Privacy Policy - Multiplicity

Who is responsible for your data

Multiplicity is run by an individual trading as Multiplicity, established in the United Kingdom. That individual is the data controller for the personal data described here. Multiplicity is not a limited company.

Email: hello@multiplicity.fm. It is read by the person who runs the service.
Our trading name, and a postal correspondence address, are available on request.

We are not required to have a Data Protection Officer, and we do not have one. Data protection questions go to the address above.

Account and sign-in

Email address to identify your account, reopen your saved Canon, send your sign-in code or recovery link, and send product emails only if you have opted in.
Name or display name if you provide one while generating.
Sign-in security data so we can keep your account secure: one-time sign-in codes, and, if you choose to add one, a passkey. For a passkey we store only its credential identifier and public key, never your fingerprint, face or device passcode, which stay on your device.
Session records for the devices you stay signed in on. We store a hashed session token and a hashed record of the browser or app, not the raw values, and you can sign out to revoke a session.

Connected music services and listening history

You choose which sources to connect. Depending on the source, this can include:

Last.fm: your Last.fm username and your scrobbles with their timestamps, used to build and update your surfaces.
Apple Music: the library or play-history file you export and upload, used to score albums and build your Canon.
Spotify: where you connect it, your Spotify account email, profile, saved library and top items (Spotify connection is currently limited to invited testing).
Google or Apple sign-in: the basic identifier and email those services return when you use them to sign in.

You decide what to connect or upload. Connecting a source and uploading a file are optional actions you take deliberately.

What Multiplicity creates from your listening

From the history you connect, Multiplicity generates and stores your Canon, Rotation, Ledger, Records, Rankings, identity and profile surfaces, along with weekly and monthly history snapshots, so you can reopen and compare them over time.

Plan and billing

If you take a paid plan, we store your plan or tier and the identifiers needed to manage it, including a Stripe customer reference, checkout records and subscription status. Payments are processed by Stripe; we do not store your full card details, and billing data is not your listening history.

Purchases and plan changes happen on the multiplicity.fm website. No purchase can be made inside the Multiplicity apps.

Analytics and diagnostics

Product analytics such as pages visited, referral details and campaign attribution, tied to a salted, hashed visitor identifier rather than your raw IP address.
Diagnostics if you report a problem or an error occurs: details such as your browser or app user-agent, language, screen size, the page and your account and plan context, so we can fix faults.

We use your IP address in the moment to derive the hashed visitor identifier and to rate-limit sign-in attempts; we do not store it as a standalone record.

How we use it

To generate, save and let you revisit your Canon, Rotation, Ledger, Records and identity surfaces.
To remember your account, keep you signed in securely, and apply the limits and features of your plan.
To store history snapshots so comparison and history features work over time.
To understand traffic, diagnose faults and improve the product.
To send product emails only if you have explicitly agreed to receive them.

Why we are allowed to use it

UK data protection law requires us to have a lawful basis for each purpose. Ours are:

To perform our contract with you for your account, sign-in, the listening history you connect, the surfaces we generate and store, and your plan and billing. This is the data without which Multiplicity cannot do the thing you asked it to do.
Our legitimate interests for product analytics, diagnostics, keeping the service secure and preventing abuse. Our interest is in running a service that works and can be fixed; we use a salted, hashed visitor identifier rather than your raw IP address so this stays as light as it can be.
Your consent for marketing and product emails, and for each music service you choose to connect. You can withdraw consent at any time, and withdrawing it does not affect anything done before you did.
Our legal obligations for the billing and payment records that tax law requires us to keep.

Where we rely on legitimate interests, you have the right to object. See "Your rights" below.

Automated processing

Your Canon ranking, your Rotation and your Taste Family are produced automatically from your listening history. That is the product working as intended, and it has no legal or similarly significant effect on you. We do not use your data for automated decisions about credit, employment, eligibility or anything of that kind, and we do not profile you for advertising.

Generating editorial with AI

To write the editorial and identity text on your Canon and Rotation, Multiplicity sends the relevant listening-derived details, such as album and artist names and the patterns drawn from your history, to our AI provider, Anthropic, which processes them to generate that text. We do not send your email address, billing details or raw account data for this, and we do not use it for advertising.

Service providers we share data with

We do not sell your personal data. We share it only with the providers that run the service, who process it on our behalf under their own terms:

Railway hosts the application and stores your data.
Klaviyo sends our account and product emails, including your sign-in code and recovery emails, and holds the related contact and engagement data.
Anthropic processes the listening-derived prompts described above to generate editorial and identity text.
Stripe processes payments and holds your billing details.
Last.fm, Spotify, Google and Apple are the sources you connect; we exchange data with them only for connections you choose to make.
Deezer and the Apple iTunes Search service are queried by album and artist name to fetch artwork; we do not send them your personal data.

We use these providers because the service needs them, not to widen who sees your data.

Sending data outside the UK

Some of the providers above operate outside the United Kingdom, mainly in the United States and the European Economic Area. Where your data is transferred outside the UK, it is protected by one of the transfer mechanisms UK law recognises:

a UK adequacy decision, where the destination country has one, which currently covers the European Economic Area, or
the UK International Data Transfer Agreement, or the EU Standard Contractual Clauses together with the UK Addendum, which is the route used by our United States providers.

If you want to know which mechanism applies to a specific provider, email hello@multiplicity.fm and we will tell you.

Cookies and similar storage

Multiplicity sets a small number of cookies, and no advertising or cross-site tracking cookies at all. We do not sell or share anything with an ad network.

A session cookie that keeps you signed in. Without it the service cannot work.
An account cookie that remembers which account this browser is using, so you can return to your Canon without signing in again.
Interface cookies that remember small choices, such as a banner you have dismissed, so we do not show it again.
Analytics storage for the salted, hashed visitor identifier described above, so we can count visits without identifying you by IP address.

You can clear or block cookies in your browser settings. If you block the session and account cookies, signing in and staying signed in will stop working.

Age

Multiplicity is not intended for children. You must be at least 16 to use it, as set out in the Terms of Service. If you believe someone under that age has an account, email hello@multiplicity.fm and we will remove it.

The Multiplicity apps

The iOS and Android apps load the Multiplicity service inside a native frame. They behave the same as the website for data, with two clarifications: no purchase can be initiated inside the apps, and plan changes are made on multiplicity.fm. The apps do not stream or play music; they read the history you connect and reflect it back as your surfaces.

Storage and retention

Your uploads, generated surfaces, history snapshots, account and plan data are stored in the application backend on our hosting so you can reopen them. The principle we work to is simple: we keep what the archive needs in order to still be your archive, and no more.

Your account, listening history and generated surfaces are kept while your account exists, because reopening them years later is the point of the product. They go when you delete your account.
Billing and payment records are kept for as long as tax law requires. As a self employed business we must keep records for at least five years after the 31 January submission deadline for the relevant tax year. These records are kept even after an account is deleted, with your personal details removed from them where we can.
Analytics and diagnostics are kept only while they are useful for understanding traffic and fixing faults, and are tied to a hashed visitor identifier rather than to you by name.
Session records end when you sign out or the session expires.
A record that a deletion request was made is kept after the deletion, because it is how we can show the request was honoured.

We are in the process of writing a specific number of months against each of the categories above. Until then, the honest answer is the principle stated here rather than a figure we have not yet committed to. Data held by our providers, such as Klaviyo and Stripe, is retained or removed according to their own terms.

Your rights

Under UK data protection law you have the right to:

Be told what we hold about you and why. That is what this notice is for.
Get a copy of the personal data we hold about you.
Have it corrected if it is wrong or incomplete.
Have it deleted, in the circumstances the law provides for.
Restrict how we use it while a question about it is being resolved.
Object to us using it where we rely on legitimate interests, and to object to marketing at any time, with no reason needed.
Receive it in a portable form, where we hold it on the basis of your consent or our contract with you.
Withdraw consent at any time where we rely on it.

To use any of these, email hello@multiplicity.fm. We will respond within one month. Using your rights is free, and we will not treat you differently for it.

Your choices and deletion

Delete your account: you can request deletion from within the product at /account/delete (under You and Profile). We record the request and complete the removal of your stored account and listening data within 30 days, and email you when it is done. Signing out alone does not delete your data.
Marketing: you can opt out of product emails at any time using the unsubscribe link or by contacting us.
Access or removal: you can ask us about, export or remove your stored data by contacting us, and we will also ask our providers to remove it where applicable.

Deletion removes your account and the listening data tied to it. The billing records described under retention are kept where tax law requires, with your personal details removed from them.

Complaining to the ICO

If you are unhappy with how we have handled your data, please tell us first at hello@multiplicity.fm so we can put it right.

You also have the right to complain to the UK's data protection regulator, the Information Commissioner's Office, at ico.org.uk. You do not have to come to us first, and complaining to the ICO does not cost anything.

If the service ever closes

If Multiplicity ever had to close permanently, we would tell everyone with a paid plan by email and give as much notice as we reasonably can, give you a reasonable opportunity to save or export what we hold for you so far as that is technically feasible, and then delete the personal data we hold, keeping only what tax law requires. Section 14 of the Terms of Service covers the commercial side of the same question.

What we don’t do

We do not sell your personal data.
We do not make your Canon public by default.
We do not claim affiliation with Apple Music, Spotify or Last.fm.

Contact

If you want to ask about, export or remove your stored data, contact hello@multiplicity.fm.

How Multiplicity handles your data.