Memfault Location Services

Memfault Location Services give your devices fast, accurate, low-power location data. Without having to connect to multiple vendors and APIs, you can use our Location Services to get Single Cell or Multi Cell, Wi-Fi, or combine Wi-Fi and Cell into a Groundfix.

You can now discover, configure, and start using Location Services directly from

Memfault, without leaving the platform to manage tokens or read separate docs.

Sign up

If you do not yet have an account, create a Memfault account to get started.

What you get

Memfault supports four services types, single and multi-cell, Wi-Fi, and Groundfix which determines the most accurate fix between Wi-Fi and cell, all in one API.

Service	Typical accuracy	Power savings	GNSS required	Use when
Single-cell (SCELL)	Less than 1000 m	High	No	The device is power-constrained or indoor, and coarse location is acceptable.
Multicell (MCELL)	Less than 700 m	High	No	Several cells are usually in range and tighter cellular accuracy is needed.
Wi-Fi	Less than 100 m	High	No	The device operates indoors with Wi-Fi access points in range.
Groundfix	Less than 700 m	High	No	When you want the best fix determined from cell and Wi-Fi access points in range.

note

Accuracy values are typical reference figures and not guaranteed. Reported uncertainty is the horizontal positioning error — the radius around the returned coordinates within which the device sits with roughly 68% probability.

Setting up Location Services via API

You can set up location services directly from your cloud via API.

• Authenticate with an organization auth token (OAT) scoped to Location Services.
• All requests go through the REST API.

Get started

Step 1: Enable Location Services in your account

Reach out to your Customer Success Manager or Account Executive and we'll enable Location Services in your account so you can get started trying up to 1500 requests per month for free.

Step 2: Find your organization and project slugs

You need both slugs to construct Location Services API URLs.

1. In the left sidebar, click Project Settings → General.
2. Copy the Organization Slug and Project Slug values from the Details panel.

Step 3: Run the Location Services setup guide

Memfault includes a guided wizard that explains your options and gets you to a working request in a few minutes.

1. Select Location Services from the project sidebar.
2. Step through the education and setup flow:

   1. Service Types. Expand the SCELL, MCELL, and Wi-Fi cards to compare accuracy, power, and prerequisites.

   2. Access Methods and OAT Setup. Choose if you plan to send requests from your own cloud via API or connect devices in-platform.
   3. Plan and Pricing. Review billing details and confirm the plan.
3. The app marks the wizard complete on the server, so it persists across browsers and reloads.

Skipping the wizard

Click Skip for now on any step to jump straight to the Location Services overview page.

Step 4: Generate an organization auth token (cloud-to-cloud)

You need to generate an Organization Auth Token (OAT). You do not need to leave the Location Services page to do this.

1. On the Location Services overview page, find the Send API Requests section.
2. Click Generate token.
3. Enter a description (for example, Location Services) and click Create.
4. Copy the token immediately and store it in a secrets manager. The token is shown only once.
5. (Optional) Click Manage tokens to view existing tokens or revoke one.

warning

Only organization admins can create OATs. If you are not an admin, the page shows a notice — ask your admin to complete this step. Tokens grant the same permissions as an organization admin via the API. Treat them like passwords: do not commit them to source control or share them in chat.

Once the organization has at least one token, the Generate token button is hidden. Use Manage tokens to add more if you need to rotate.

You can also create OATs directly from Admin → Organization Auth Tokens → Create Token if you prefer the settings route.

Step 5: Make your first request

The base URL for Location Services endpoints is:

https://api.nrfcloud.com/v1/organizations/<YOUR_ORG>/projects/<YOUR_PROJECT>/location

Replace <YOUR_ORG> with your Organization Slug and <YOUR_PROJECT> with your Project Slug from Step 2.

The overview page shows a pre-filled sample cURL request using your actual slugs. You can copy it directly from there, or use the following Wi-Fi example:

curl -v -X POST \
  https://api.nrfcloud.com/v1/organizations/<YOUR_ORG>/projects/<YOUR_PROJECT>/location/wifi \
  -H "Authorization: Bearer $NRFCLOUD_OAT" \
  -H "Content-Type: application/json" \
  -d '{
    "accessPoints": [
      {
        "macAddress": "30:86:2d:c4:29:d0",
        "signalStrength": -45
      },
      {
        "macAddress": "3c:37:86:5d:75:d4",
        "signalStrength": -45
      }
    ]
  }'

A 200 OK response with a JSON body containing lat and lon confirms that your OAT and slugs are working.

Tenant ID header

Requests to the /wifi endpoint must include a valid x-nrfcloud-tenantid header. Missing or unrecognized headers are rejected. The cell and ground-fix endpoints derive the tenant from the bearer token.

Service costs and plans

Location Services usage is metered per request type. To get started with pricing and to try it out for free, contact your Customer Success Manager.

Memfault stores location history for six months.

Method details

The rest of this page covers each method in depth and shows how it works on the device.

Cellular location (SCELL and MCELL)

Cell-based location identifies the nearest cell tower, or a triangulated position based on multiple cell towers, based on the cell tower IDs and signal strength. While generally less accurate, its low cost and low bandwidth can give you general positioning for when battery and bandwidth are a concern.

• SCELL. Uses only the serving cell. Lowest accuracy, lowest cost. Good for power-constrained or indoor devices.
• MCELL. Uses the serving cell plus measured neighbor cells (nmr). More accurate, marginally more bandwidth.

Find cell parameters on the device

You need MCC, MNC, TAC, and ECI to construct a request. Get these with the Cellular Monitor app in nRF Connect for Desktop:

1. Open the Cellular Monitor app.
2. From the Dashboard, note the values:
   • Mcc and Mnc appear together as the PLMN ID. The first three digits are MCC; the last two or three are MNC.
   • CellId is the ECI.
   • TAC is a five-digit tracking area code.
3. For neighbor cells, open the debug log and search for nmr. Each entry has earfcn and pci.

MCC/MNC validation

Location Services validates MCC and MNC against the ITU-T E.212 ranges. Out-of-range values are rejected at the API. Pull the values straight from the modem rather than hand-coding them.

Call the ground-fix endpoint

The GetGroundFix endpoint combines cell and Wi-Fi positioning in one request. It tries Wi-Fi first, then falls back to cellular.

curl --location --request POST \
  "https://api.nrfcloud.com/v1/organizations/<YOUR_ORG>/projects/<YOUR_PROJECT>/location/ground-fix" \
  --header "Authorization: Bearer $NRFCLOUD_OAT" \
  --header "Content-Type: application/json" \
  --data-raw '{"lte":[{"mcc":'"$MCC"',"mnc":'"$MNC"',"tac":'"$TAC"',"eci":'"$ECI"'}]}'

Include an nmr array of neighbor cells to improve accuracy. The response includes lat, lon, uncertainty, and fulfilledWith.

Results are written to the location history which you can access for up to six months through the GetLocationHistory.

Wi-Fi location

The device scans for nearby Wi-Fi access points, sends their MAC addresses to

Memfault, and receives coordinates derived from a third-party database. Wi-Fi is often more accurate than cellular for indoor devices.

note

At least two Wi-Fi access points are required for both the /wifi and ground-fix endpoints for privacy reasons.

Reverse geocoding

Convert coordinates into a human-readable address with GetGeocoding. The response includes at minimum the country and the state, province, or region.

Higher-accuracy input coordinates (Wi-Fi) produce higher-accuracy addresses than coarse cellular fixes.

Location history

Memfault stores every successful position request for six months. Pull the history with GetLocationHistory, or view it on the device page in Memfault.

API requirements

All Location Services REST requests authenticate with an Organization Auth Token (OAT) passed as a Bearer token in the Authorization header.

For API requests, include your OAT as follows:

Authorization: Bearer $NRFCLOUD_OAT

Troubleshooting

Cell location requests fail

• Open Cellular Monitor and confirm the device has a signal and the correct COM port is selected.
• Wait two or three minutes after boot — connection setup is sometimes slow.
• Verify network coverage with your carrier.
• For iBasis SIMs, check the data balance under Device Management > SIM Cards.

Coordinates do not match the actual device location

The returned coordinates are the center of an uncertainty circle. The device sits somewhere inside that circle with ~68% probability, not necessarily near the center.

Uncertainty values are unusually large

High uncertainty usually means one of:

• Low cell density (rural).
• The ECI is unknown and the service fell back to a tracking-area estimate. Tune behavior with the fallback query parameter.
• The cells or access points in the request are physically spread out — for example, after a cell ID reassignment.

MCELL produces the same result as SCELL

Two reasons:

• The neighbor cell overlaps so much with the serving cell that it does not move the estimate.
• The neighbor cell is not yet in the Memfault database, so only the serving cell was used.

MCELL is still worth sending: it raises the odds of a valid result when the serving cell alone is unknown.

Wi-Fi request returns MAC address ... is a local MAC address

Locally administered MAC addresses cannot be used for positioning — they are not globally unique. Check the second-least-significant bit of the first octet: if it is 1, the address is locally administered. Filter these out client-side, along with mobile hotspots (which return unreliable positions because the access point itself moves).

My /wifi request is rejected

Confirm the x-nrfcloud-tenantid header is set to a valid tenant. Requests with a missing or unrecognized tenant header are rejected.

Why do the API docs link to nRF Cloud APIs?

Memfault was acquired by Nordic Semiconductor in July 2025 and is in the process of integrating with nRF Cloud, which was Nordic Semiconductor's cloud offering. The Location Service APIs are powered by nRF Cloud.

Next steps

• Open the Location Services wizard in Memfault to set up your organization.
• Contact your Customer Success Manager to get started with setup and pricing.
• Migrating from Unwired Labs? Read our API Migration guide to get started.