Privacy Policy

The short version

PLCFLOW Technologies Inc. collects the minimum needed to run plcSim: an account if you make one, the projects you save, and short-lived technical data to keep the service working and fair. We collect anonymous, cookieless usage analytics to improve the product — never linked to your account, and you can opt out. We run no advertising, and we never sell or rent personal data.

If you use plcSim as a guest

No account, no profile, and none of your work is saved. To stop one visitor from consuming the whole simulator, the API counts concurrent sessions per IP address, so your IP address is held in the server process's memory for the life of your session.

One thing does outlast the visit: a line in our run log recording that a guest ran a simulation, when it started and stopped, and whether the logic was one of our built-in examples or a program of their own. It carries no account, no IP address, and nothing from the program itself. We use it to plan capacity.

Under the GDPR an IP address is personal data, so to be explicit about it: it is never written to our database, never logged for analytics, and never used to build a profile. It exists only in memory, only as a rate-limiting key, and disappears when the session ends. Guest sessions are reaped after about five minutes idle and are capped at one hour of life regardless, so this data is measured in minutes.

If you create an account

• Account details — your email address, a display name, and either a hashed password or an identifier from the sign-in provider you chose. We never see your password in readable form, and never receive your password from an OAuth provider.
• Sessions — a session token with its expiry, plus the IP address and browser user-agent of the sign-in, which is how you stay signed in and how suspicious activity can be spotted.
• Your projects — the name, source, and dialect of each program you save. This is your content, not our data; see the Terms.
• Preferences — small settings such as your instruction naming and default scan rate.
• Feedback you send us — if you use the in-app feedback form, the message you write, the category you chose, the page you were on, and your browser's user-agent string, kept with your account so we can follow up.
• A record of your simulator runs — when a run started and stopped, the plan you were on, and whether the logic was one of our built-in examples (and which one) or your own program. It never records the program itself, its name, or anything inside it: a program you wrote is stored only as the word “own”. We keep it to plan capacity and to see which examples are worth building more of.
• An activity record — a dated list of significant actions on your account: signing up, creating, renaming or deleting a project, changing settings, and subscription changes. It stores the action and which item it affected, never the contents of your programs. We keep it to support you, investigate problems, and have an auditable record of any administrative change we make to an account.

If you ask to be notified about paid plans

Paid plans are not open yet. If you use a Notify me button on the pricing page, we store your email address, which plan you asked about, and the date. If you are signed in we use the address on your account and do not ask you to type one. We keep it for one reason: to email you once when those plans open. It is never sold, never shared, and never sent to our analytics provider, which only records that someone asked and about which plan. Ask us at support@plcflow.io and we will remove you from that list.

Because this form is open to visitors who are not signed in, we also store a one-way hash of your IP address with it, so a single source cannot flood the list. The hash cannot be reversed to an address and is used for nothing else.

Email from us

If you have an account, your email address, the name on your account, and your plan tier are held by Resend, our email provider, in a list of plcSim accounts. We use that list for one thing: product updates— occasional email about new plcSim features, sent on the basis of the account you hold with us. Every such message carries a working unsubscribe link, as Canada's anti-spam law (CASL) requires, and the same switch is on your account page. Turning it off takes effect immediately and is never undone by us.

We do not currently send any automated account email — no welcome message, no password reset, no receipts from us (invoices come from Stripe). If that changes, this page will say so. The address is never sold or shared for anyone else's marketing, and it is not sent to our analytics provider.

If you buy a paid plan

Payments are handled by Stripe, our payment processor. Your card details go directly to Stripe on their checkout and billing pages — we never see or store your full card number. What we keep is your plan, its subscription status and billing period, and identifiers referencing your Stripe customer and subscription records; Stripe keeps the invoice and payment history, which you can access from the billing portal on your account page.

Product analytics

We use PostHog to understand how plcSim is used — which features get used, where imports succeed or fail, and where people give up — so we can make the product better. It is configured deliberately narrowly:

• Anonymous and cookieless. The analytics library keeps its state in memory only: it sets no cookies, stores no identifier in your browser, and each page load starts as a fresh anonymous visitor. We never tell it who you are, even when you are signed in — events are not linked to accounts.
• What an event contains — the action (for example a session being created), the page, technical context such as browser and operating system, and an approximate location derived from your IP address by our analytics provider, which — like any server you connect to — receives your IP as part of the request. We do not store IP addresses in analytics events.
• No session recording, no autocapture — only the specific events we define, and never the content of your programs.
• Opt out any time — in the app, open the account menu (the circle at the top right, signed in or not) → Settings… → Product analytics. Opting out stops all analytics traffic from your browser and is remembered on this device.

Error monitoring

Separately from analytics, we use Sentry to be told when something breaks — a page that fails to load, an import that crashes, an API error. This is how a bug gets fixed rather than silently repeating for everyone who hits it.

• What a report contains — the error message and the stack trace of the code that failed, the page or endpoint it happened on, and technical context such as browser, operating system, and the version of plcSim that was running.
• What it does not contain — we turn off the provider's optional personal-data collection, and every report is stripped of your account identity, cookies, request bodies, and URL query strings before it leaves your browser or our server. One header is kept — your browser's user-agent string — because it is what tells us which browser and operating system a crash came from, and that is the first thing needed to reproduce it. There is no session recording here either.
• Not covered by the analytics opt-out — and deliberately so. Crash reports are not behavioural measurement: they carry no identity, set no cookie, and build no profile. Switching them off for the people most likely to be hitting bugs would make the service worse for them without protecting anything.

What we do not do

• No advertising, and no advertising identifiers.
• No card numbers. Payment details go directly to Stripe; we never see or store them.
• No selling or renting of personal data, and no sharing it for others' marketing.
• No AI training on your work. The programs you upload, import, or save are never used to train AI or machine-learning models — ours or anyone else's.
• No session recording, and no tracking of you across other websites.
• No automated decision-making with legal or similarly significant effects.
• No marketing email beyond product updates about plcSim itself — which you can switch off at any time — and every one of those messages has a working unsubscribe link, as Canada's anti-spam law (CASL) requires. No third-party offers, ever.

Why we are allowed to process it

Where the GDPR or similar law applies: account data and saved projects are processed to perform our contract with you; billing and subscription data is processed to perform that contract and to meet our legal obligations, such as keeping tax records; rate-limiting data is processed under our legitimate interest in keeping a free service available and resistant to abuse; anonymous product analytics is processed under our legitimate interest in improving the product — kept proportionate by being cookieless, account-unlinked, and opt-out; error reports and the account activity record are processed under our legitimate interest in keeping the service working, secure, and accountable — kept proportionate by carrying no identity in the first case and no program content in the second; product-update email is sent under our legitimate interest in telling account holders what has changed in the product they use — kept proportionate by being infrequent, about plcSim only, and switched off the moment you say so; and anything else is processed with your consent, which you can withdraw.

Cookies

plcSim sets one cookie: your sign-in session. It is strictly necessary to keep you signed in, so it needs no consent, and it is the reason you see no cookie banner. Our analytics runs cookieless — it sets no cookies and stores nothing in your browser. There are no analytics, advertising, or cross-site tracking cookies. Some preferences (including your analytics opt-out) are kept in your browser's local storage and never leave your device unless you sign in.

Where your data is processed

We use a small number of infrastructure providers, each handling data only to run the service on our behalf:

• Vercel — hosts the web application and handles sign-in requests.
• Fly.io — runs the simulation API in the United States (Secaucus, NJ). It holds no database; simulation state exists only in memory, apart from the SCADA endpoint records described below.
• Akamai (Linode) — hosts the database holding accounts, projects, and preferences.
• GitHub or Google — only if you choose to sign in with one of them, and only to confirm your identity.
• PostHog — processes the anonymous product-analytics events described above, in the United States.
• Stripe — processes payments for paid plans, in the United States, and holds the card details and invoice history we never see.
• Sentry — receives the stripped crash reports described above, in the United States.
• Resend — holds the account email list described above and delivers what we send to it, in the United States.

This means data may be processed outside your country, including in the United States. Where required, transfers rely on appropriate safeguards such as the European Commission's standard contractual clauses.

How long we keep it

• Guest session data, including IP — in memory only; minutes, and never more than one hour.
• Running simulation sessions — discarded when idle, when you stop them, or when the server restarts.
• SCADA endpoint records — a published endpoint is deliberately the one thing that survives a restart: the program it serves, its tag values, and the endpoint's credentials are written to the simulation server's storage for as long as it stays published, and deleted when you take it down.
• Sign-in sessions — until they expire or you sign out.
• Analytics events — anonymous events are kept for up to 12 months, then deleted.
• Error reports — kept for up to 90 days, then deleted.
• The run log — kept as a capacity record. Like the activity record below, it is de-identified rather than erased when you delete your account: the link to your account is removed and the line stays, saying only that a simulation ran.
• Feedback and the activity record — de-identified rather than erased when you delete your account: the link to your account is removed, so what remains is the message you wrote or the fact that an action happened, with nothing tying it to you. We keep them at that point because product feedback and a record that an administrative change was made stay useful after an account is gone.
• Paid-plan notification requests — until we email you when those plans open, or until you ask us to remove you, whichever comes first. We delete the list once it has been used.
• The email contact record — for as long as your account exists. It is removed from our email provider when we delete your account, along with any preference you set on it.
• Account and projects — until you delete them or ask us to delete your account, after which they are removed from the live database. Projects and settings are deleted together with the account. Residual copies in encrypted backups expire on the backup schedule, within 30 days.
• Billing records — subscription and invoice records are kept as long as tax law requires them, which in Canada is generally seven years, even if you delete your account.

Files you don't save

Most of what happens in plcSim never reaches our database. When you drop in an L5X, the import and validation step is stateless: the file is parsed as part of the request and nothing from it is written to disk or to a log. The imported program lives in your browser, not on our servers.

If you run it, the program is held in the memory of your simulation session for as long as that session is alive. Guest sessions are dropped after about five minutes idle and are capped at one hour of life regardless. Free accounts keep an unsaved draft in your own browser's storage, which we cannot read. Saved projects on our servers start at Standard, and those are the ones the retention terms above cover.

There is one exception, and it only applies if you use it. Publishing a session as a SCADA endpoint writes that session's program, its current tag values, and the endpoint's credentials to the simulation server's own storage — that is what lets a SCADA client you configured once keep working after we deploy an update. The record is deleted when you take the endpoint down. Publishing an endpoint needs an account; guests cannot do it.

Your rights

Depending on where you live — including under Canada's PIPEDA and Quebec's private-sector privacy law, the GDPR, and similar laws — you may have the right to access, correct, delete, export, or restrict processing of your personal data, to object to processing based on legitimate interests, and to withdraw consent. Email support@plcflow.io and we will respond within the time your law requires — within one month under the GDPR. You may also complain to your privacy regulator: in Canada, the Office of the Privacy Commissioner (or the Commission d'accès à l'information in Quebec); in the EU or UK, your local data protection authority.

Children

plcSim is aimed at engineers and students of industrial automation and is not directed at children under 13 (or under 16 where local law sets that threshold). We do not knowingly collect their data; if you believe a child has given us data, contact us and we will delete it.

Security

Traffic is encrypted in transit, passwords are stored hashed, and the simulation API never touches the database — it verifies signed tokens instead, so a compromise there exposes no stored accounts. No system is perfectly secure, and we do not claim otherwise. If a breach ever creates a real risk of harm to you, we will notify you and the appropriate authorities as the law requires.

How your session is separated from everyone else's

Each running simulation gets its own scan engine, with its own program, its own tag database and its own timers. No engine can see or reach another engine's data, and there is no shared state between them.

Several sessions do run inside one server process, the same way several programs run on one PC. That is a software boundary, not a hardware one. If your work needs a hardware boundary, a single-tenant deployment in your own environment is the honest answer, and it's something we can talk about.

Changes

We will update this page when our practices change and revise the date at the top. Material changes will be signalled in the app.

Contact

PLCFLOW Technologies Inc. is the controller of the personal data described here, and its Privacy Officer is the person accountable for it. Privacy questions and rights requests: support@plcflow.io.