Postlad/Guides

A free IoT dashboard for a student project

A semester is months long, the demo is the week before the deadline, and the question your marker asks is "what does this look like over time?". So the thing that matters in a free dashboard is not how pretty the widgets are — it is whether your week-2 data is still there in week 12, and whether the person marking it can look at your chart without making an account. Here is exactly what the Postlad free tier gives you on both counts.

Guide·free-tier figures current August 2026

The shape of a term, and where dashboards fail it

A student project usually runs something like this:

• Week 2 — the sensor works, data appears in a chart, everyone is pleased.
• Week 6 — you change the enclosure, the device is offline for four days, nobody notices.
• Week 11 — you write the report and want a graph of the whole term.
• Week 12 — you demo it, and a marker asks "what does the trend look like over time?"

Weeks 11 and 12 are where a dashboard either earns its place or quietly ruins your afternoon. If the history only goes back a day, weeks 2 to 10 do not exist: you have a live readout rather than a data logger, and the report gets written around a screenshot you happened to take in week 3. The fix is not a nicer chart. It is retention long enough to cover a term, and an export button for the numbers you want in an appendix.

What the free account gives you

This is the whole free tier, written out. There is no trial clock on it and no card on file — it is the plan, not a preview of the plan.

Last checked August 2026. The rollup engine behind the 12-month figure is running; the honest caveat is that Postlad itself is younger than a year, so no stream has a full year in it yet.

The bit nobody plans for: showing it to your marker

You have built a thing. Now a professor, a lab partner, an external examiner or a parent needs to look at it. The realistic options are:

1. Screenshots in the report. Fine, everyone does it, and it proves nothing about whether the thing is still running.
2. Ask them to make an account. They will not. If your demo starts with "so first, sign up and confirm your email", you have already lost the room.
3. A link they click. They see live data. That is the whole story.

Option 3 is the default here. Every stream can be given a public link, and a viewer opening it gets the current value, the chart and the last-seen time with no account, no login and no app. It works in a private window, it works on a phone in a lab corridor, and it works on the marker's laptop while you talk.

One practical habit worth forming whatever you end up using: open your own share link in a private browsing window, in week 2. That is the two-minute test that tells you whether your demo will work, and the night before the deadline is a bad time to discover the answer.

Getting the data in

One HTTP GET, with the reading in the query string. No SDK, no client library, no auth header, no broker to stand up:

GET https://api.postlad.com/u?k=YOUR_KEY&f1=23.5&f2=61

That is four lines on an ESP32 and two on a Raspberry Pi. The complete versions are written out, with the wiring and the failure cases: the ESP32 sketch and the Raspberry Pi logger, the second of which covers buffering readings through a network outage — which is exactly the week-6 problem above.

The server timestamps each reading as it arrives, so you do not need a real-time clock module on the device unless it logs while offline.

What it will not do

Worth knowing before you commit a term's work, because we would rather you found out here: there is no built-in statistical analysis, no rules or alerting engine, and no mobile app builder. The free rate limit is one reading every 5 seconds, but the monthly quota of 100,000 stored points is the number that actually binds — if your project needs 10 Hz sampling, average on the device and send the average, or use something else. And Postlad is new; a service with a decade behind it has a track record that we simply do not have yet.

Signing up takes about a minute

The whole flow, end to end:

1. Enter your email at app.postlad.com/login.
2. Click the magic link we send you — that is the entire login. There is no password to choose and none to forget in week 9.
3. Copy your write key from the streams page and paste it into the GET line above.
4. Send one reading. The stream gets a live page the moment the first value lands; there is no dashboard to build first.

No credit card is asked for at signup, and none is asked for later — this is a free tier, not a trial that turns into a bill. We email you about your account and nothing else: no newsletter, no drip campaign.

FAQ

Is it actually free, or free for now?

Free, as written above, and the limits are published rather than hidden behind a "contact us" so they can be held against us later. If a free-tier limit ever changes, the change will be announced rather than discovered — and your CSV export is on every tier with no cap, so your data is never hostage to that conversation.

Do I need a credit card?

No — not to sign up, and not after any period of time. There is no trial clock. Signup is an email address and a magic link.

Can my professor see my dashboard without making an account?

Yes, and it is the default. A stream can be given a public link that shows the live chart to anyone who opens it, with no account, no login and no app install. Test it early by opening your own link in a private browsing window.

Will my data still be there at the end of the semester?

Yes. Every reading is kept at full detail for 30 days, and after that an hourly minimum, maximum and average is kept for 12 months. So the last month of a term is fine-grained, and the months before it are still on the chart as an hourly trend rather than a gap.

How often can I send readings on the free tier?

One every 5 seconds is the rate limit, but the account quota of 100,000 stored points a month is the ceiling that matters — that is one reading every 26 seconds sustained across a whole month. Thirty seconds is a comfortable interval for something you leave running all term. If you need faster sampling, average several readings on the device and send the average.

Can I get the raw numbers out for my report?

Yes. CSV export is a button on the stream page, on every tier, with no cap. Take an export periodically as you go — it is good practice with any service, ours included, and it means a report deadline never depends on someone else's uptime.

Does this work for a group project?

Partly, and here is the honest shape of it: the account is one login, so one of you holds the write key, but the share link means everyone else — group members, supervisor, marker — can watch the live chart without an account of their own. Multi-user accounts are not built yet.

What if my project outgrows the free tier?

Then tell us what it needs: hello@postlad.com reaches a person. Coursework that fits inside the limits above should stay on the free tier, and we would rather say that plainly than sell you something you do not need.

Can I self-host something instead?

If your course is about the infrastructure, yes, and it is a good exercise — but budget real time for it, and remember that "my laptop" is not a server your marker can reach. A cheap VPS or a Raspberry Pi with a tunnel is the usual answer. The Raspberry Pi logger page covers running a logging service properly, including surviving reboots, and that part is worth reading whichever way you go.