# MicroSIP caller ID for Windows — caller name, line type & risk signal

- Category: PBX & softphones
- Published: June 3, 2026 · Updated: June 15, 2026
- Canonical: https://numbers.online/docs/integrations/microsip

Show a caller's name, line type, and a low-confidence risk signal as a Windows
toast the moment an inbound call rings your **MicroSIP** softphone. MicroSIP runs
a command on each incoming call; that command asks **Numbers Online** about the
caller and pops a desktop notification.

> **Positioning.** This is a desktop-softphone *demo* of the Numbers Online lookup
> API — a quick way to see the signal on your own screen. For production call
> flows the real integration point is your PBX/SBC (see
> [`asterisk-freepbx.md`](./asterisk-freepbx.md)), where the lookup can label,
> route, or challenge a call before it reaches an extension. Numbers Online
> returns *supplementary* identity and risk signals; the operator keeps every
> routing and blocking decision. The API never asserts that a call is lawful,
> unlawful, "safe", or "spam".

## What you get

On each inbound call a toast appears with:

- the caller name (CNAM) when available, otherwise *No name available*;
- the caller's national number, line type, and country;
- a **risk signal** rendered as `Risk signal: <n>/99 (low-confidence supplementary signal)`.

An optional operator-chosen label (default `Possible nuisance call`) is prefixed
to the name only when the risk score meets a threshold you set. Risk wording is
opt-in by design — clear `$RiskTag` in the script to never surface it.

## Files

Both files are downloadable below — and from the [integrations page](/integrations):

| File | Role |
|------|------|
| [`NumbersOnlineLookup.ps1`](/integrations/microsip/NumbersOnlineLookup.ps1)     | PowerShell: normalize the number, call the API, show the toast |
| [`numbers-online-lookup.bat`](/integrations/microsip/numbers-online-lookup.bat)   | One-line wrapper MicroSIP invokes; forwards the caller number to the `.ps1` |

## Setup

1. **Create an API key.** Sign up once and copy the key it returns:

   ```
   curl -X POST https://numbers.online/api/v1/account/signup ^
     -H "Content-Type: application/json" ^
     -d "{\"email\":\"you@example.com\",\"name\":\"Your Company\"}"
   ```

   The free tier is unbilled at 60 requests/min. Full docs: <https://numbers.online/docs>.

2. **Save both files** to `C:\tools\numbers-online\` so you have:

   ```
   C:\tools\numbers-online\NumbersOnlineLookup.ps1
   C:\tools\numbers-online\numbers-online-lookup.bat
   ```

3. **Set the API key** as a user environment variable named
   `NUMBERS_ONLINE_API_KEY` (the script reads it from there — it is never stored
   in the script):

   ```
   setx NUMBERS_ONLINE_API_KEY "YOUR_API_KEY"
   ```

   Open a **new** session afterwards so the variable is visible to MicroSIP.

4. **Point MicroSIP at the wrapper.** Close MicroSIP, edit `microsip.ini`, and set
   the incoming-call command under `[Settings]`. Quote the path (it contains no
   spaces here, but quoting is required if you relocate it under a path that does):

   ```ini
   [Settings]
   cmdIncomingCall="C:\tools\numbers-online\numbers-online-lookup.bat"
   ```

5. **Restart MicroSIP.** On the next inbound call you'll see the toast.

If your trunk delivers numbers for a country other than the US/Canada, open
`NumbersOnlineLookup.ps1` and adjust `$DefaultCountryCode` /
`$DefaultNationalLength` near the top.

## The raw-number caveat

MicroSIP passes the **raw SIP From user-part with zero normalization** as the
single argument. In practice that is often a 10-digit national or 11-digit
number, only rarely full `+E.164`, and can even be `anonymous` or an alphanumeric
SIP username. The script defends against this:

- non-numeric callers (`anonymous`, alphanumeric users, empty) are ignored — no toast;
- a 10-digit number gets the default country code prepended;
- an 11-digit number already starting with the country code is treated as `+`-prefixed;
- a value with a leading `+` is trusted as already-international.

Because numbers arrive without a `+`, the script interprets bare national numbers
using `$DefaultCountryCode`. A misconfigured default country code is the most
likely cause of an odd result.

## Fail-open

The integration never blocks or delays a call. MicroSIP launches the script as a
fire-and-forget side effect and **ignores its output entirely** — the toast is
the only visible product. On any guard miss, missing API key, timeout (5s), or
HTTP error (`401`/`402`/`429`/offline), the script simply exits silently and the
call proceeds as normal. No popup is not an error; it just means there was nothing
to show.

## Privacy

The script logs nothing. Raw caller numbers and your API key never touch disk or
any debug output; the key is read only from the `NUMBERS_ONLINE_API_KEY`
environment variable at runtime.

## Pricing

Billing matches the rest of the lookup API: **$0.004** per lookup that includes a
fresh CNAM dip, **$0.002** for a cache hit or when no name supplier is available,
and **invalid numbers are free**. The free tier is unbilled at 60 requests/min.

For API keys or higher rate limits: **api@numbers.online**.

## Keys & references

Keys are self-service at https://numbers.online/docs — shown once, stored only as a hash.
Machine-readable schema: https://numbers.online/api/spec · all guides: https://numbers.online/md/docs/integrations

- Previous guide: [3CX CRM integration](https://numbers.online/md/docs/integrations/3cx)
- Next guide: [AI voice agents](https://numbers.online/md/docs/integrations/ai-voice-agents-mcp)

---

Numbers Online — community-powered phone-number trust signals. Every figure on this
page is a supplementary, low-confidence signal — advisory, not a verdict on any number
or its owner.

- Canonical page (HTML): https://numbers.online/docs/integrations/microsip
- Report a call: https://numbers.online/report · Listed in error? Request removal: https://numbers.online/opt-out
- Machine guide to the phone-intelligence API: https://numbers.online/llms.txt · OpenAPI: https://numbers.online/api/spec