> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.1lookup.io/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# How accurate are the results?

## What a result means

A lookup is a **point-in-time signal** from live network, mailbox, and
data checks, not a permanent fact:

- A phone number can be active at lookup time and disconnected next
  week. Carriers recycle numbers constantly.
- An email server can accept a verification today and bounce a real
  mail tomorrow. Some servers (catch-all domains, some corporate
  filters) accept everything during verification and sort it out later,
  which is how "deliverable" can still bounce.
- Spam and risk scores are probabilities built from signals, not
  verdicts.
- Reverse lookups return what our sources hold. For some numbers,
  emails, and IPs that is nothing, and "no data found" is a normal
  answer.

## A result looked wrong?

- **One or two misses** are expected with any validation provider, for
  the reasons above.
- **A pattern across real volume** (many "valid" numbers disconnected,
  a big share of results empty) is something we want to see: write to
  us in the chat with the product you used and a few example inputs,
  and the team reviews it.
- **Credits charged on failed lookups**: tell us in the chat; we can
  pull your recent lookups with per-row status and credits, and the
  team reviews any discrepancy.

## Comparing against another provider

Different providers refresh different sources at different times, so
disagreements between vendors are normal and do not by themselves mean
either is broken. If the gap is large on real volume, send us examples.