---
title: "What is an evidence ledger? | AdBuyMCP"
description: "A six-level grading of how far each supplier integration has been proved, from sandbox only up to report verified."
url: "https://adbuymcp.com/glossary/evidence-ledger"
---

[Home](https://adbuymcp.com/) / [Glossary](https://adbuymcp.com/glossary) / Evidence ledger

AdBuyMCP's own vocabulary

# What is an evidence ledger?

A six-level grading of how far each supplier integration has been proved, from sandbox only up to report verified. The levels are sandbox only, stub, client built, contract tested, spend tested and report verified, and each is set by what a vendor has done: the presence of code or credentials counts for nothing on its own.

Also called supply verification status provenance ledger

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What it means here

## Here is what the term means for a UK buyer

The definition above holds anywhere. Buying media in the UK adds the detail below, including where AdBuyMCP does something different.

It lets anyone check AdBuyMCP's supply claims connector by connector. A client that has been written shows that the code exists, and says nothing about whether a vendor accepted a request, spent money or returned real delivery, which is why each grade is set by what the vendor has done. Of the 26 registered connectors, 22 are client-built, 3 are stubs that make no vendor call at all, and 1 has had read-only calls accepted by a live vendor. Nothing has reached spend-tested or report-verified, and the ledger keeps those two grades empty until a connector genuinely earns them.

Read next

- [The evidence grade for each of the 26 connectors Goes deeper](https://adbuymcp.com/supply)
- [The four channels in an awareness plan Channels](https://adbuymcp.com/channels)
- [What UK awareness advertising costs Cost](https://adbuymcp.com/cost)
- [What a fidelity score measures Guide](https://adbuymcp.com/guides/what-a-fidelity-score-is)

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Related terms

## These terms sit next to this one

Most confusion in media buying comes from two adjacent terms being used interchangeably, so these are the neighbours worth reading next.

- ### [Evidence provenance](https://adbuymcp.com/glossary#provenance)
  A label attached to a number recording how it was produced, so anyone reading the number can see how strong the evidence behind it is. The number may be reported by the seller, observed on your own property, estimated by a model, or established by a powered experiment.
- ### [Insertion order (IO)](https://adbuymcp.com/glossary/insertion-order)
  A contractual document committing an advertiser to buy specified advertising from a specified seller at agreed terms. The mechanism by which media that is not bought programmatically is bought instead.
- ### [Programmatic advertising](https://adbuymcp.com/glossary/programmatic)
  Buying advertising through automated systems that decide, impression by impression, whether to bid and how much to pay for it. It describes the transaction mechanism rather than a channel: CTV, audio, DOOH and display can all be bought programmatically.

Same group

## These terms are also in AdBuyMCP's own vocabulary

These are the terms AdBuyMCP either coined or uses more strictly than the category does.

- [Fidelity score](https://adbuymcp.com/glossary/fidelity-score)
- [Lawful-basis manifest](https://adbuymcp.com/glossary/lawful-basis-manifest)
- [Persona compiler](https://adbuymcp.com/glossary/persona-compiler)
- [Exposure ledger](https://adbuymcp.com/glossary/exposure-ledger)
- [Model Context Protocol (MCP)](https://adbuymcp.com/glossary/mcp)

[All 81 terms](https://adbuymcp.com/glossary)