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Evaluation metric example: String similarity

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Important notice

This workflow is provided as-is. Please review and test before using in production.

1. Workflow Overview

AI evaluation in n8n This is a template for n8n's evaluation feature. Evaluation is a technique for getting confidence that your AI workflow ...

Best for

  • Engineering automation workflows
  • AI Summarization automation workflows
  • intermediate n8n builders looking for reusable templates

Tools used

n8n-nodes-base.stickynote, n8n-nodes-base.set, n8n-nodes-base.webhook, n8n-nodes-base.evaluationtrigger, n8n-nodes-base.respondtowebhook, n8n-nodes-base.evaluation, @n8n/n8n-nodes-langchain.openai, n8n-nodes-base.code

Source and attribution

This workflow is cataloged by N8N Workflows and links back to its original n8n.io source page by David Roberts.

Original n8n.io source

1.1 Workflow description

Title
Evaluation metric example: String similarity
Workflow name
Evaluation metric example: String similarity

AI evaluation in n8n

This is a template for n8n's evaluation feature.

Evaluation is a technique for getting confidence that your AI workflow performs reliably, by running a test dataset containing different inputs through the workflow.

By calculating a metric (score) for each input, you can see where the workflow is performing well and where it isn't.

How it works

This template shows how to calculate a workflow evaluation metric: text similarity, measured character-by-character.

The workflow takes images of hand-written codes, extracts the code and compares it with the expected answer from the dataset.

The images look like this:

The workflow works as follows:

  • We use an evaluation trigger to read in our dataset
  • It is wired up in parallel with the regular trigger so that the workflow can be started from either one. More info
  • We download the image and use AI to extract the code
  • If we’re evaluating (i.e. the execution started from the evaluation trigger), we calculate the string distance metric
  • We pass this information back to n8n as a metric

1.2 Logical Blocks

This catalog entry is organized from the workflow JSON. The node-level section below shows the executable blocks available for review before importing the template.

2. Block-by-Block Analysis

Block 1 - Sticky Note1

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 2 - Sticky Note3

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 3 - Sticky Note4

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 4 - Match webhook format

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 5 - Webhook

Type / Role
n8n-nodes-base.webhook - webhook
Config choices
Version 2

Block 6 - When fetching a dataset row

Type / Role
n8n-nodes-base.evaluationTrigger - evaluationTrigger
Config choices
Version 4.6

Block 7 - Respond to Webhook

Type / Role
n8n-nodes-base.respondToWebhook - respondToWebhook
Config choices
Version 1.3

Block 8 - Evaluating?

Type / Role
n8n-nodes-base.evaluation - evaluation
Config choices
Version 4.6

Block 9 - Set metrics

Type / Role
n8n-nodes-base.evaluation - evaluation
Config choices
Version 4.6

Block 10 - Extract code from image

Type / Role
@n8n/n8n-nodes-langchain.openAi - openAi
Config choices
Version 1.8

Block 11 - Calc string distance

Type / Role
n8n-nodes-base.code - code
Config choices
Version 2

Block 12 - Download image

Type / Role
n8n-nodes-base.httpRequest - httpRequest
Config choices
Version 4.2

3. Summary Table

Workflow Evaluation metric example: String similarity
Complexity intermediate
Nodes 12
Categories Engineering, AI Summarization
Author David Roberts
Published 21 May 2025

4. Reproducing the Workflow from Scratch

  1. 1. Download the workflow JSON

    Use the JSON export at /data/workflows/4274/4274.json as the source template for this automation.

  2. 2. Import the template into n8n

    Open n8n, import the downloaded JSON, and review each node before activating the workflow.

  3. 3. Configure credentials and variables

    Replace placeholder credentials, API keys, webhook URLs, account IDs, and environment-specific values with your own settings.

  4. 4. Test with sample data

    Run the workflow manually or in a staging workspace, inspect node output, and confirm downstream systems receive the expected data.

  5. 5. Activate and monitor

    Enable the workflow only after testing, then monitor executions, errors, and rate limits during the first production runs.

5. General Notes & Resources

Review imported nodes carefully before activation. This catalog entry is intended to help you inspect the workflow structure, understand required services, and find related templates faster.

Node names, credentials, schedules, webhook paths, and external service limits may need adjustment for your workspace.

Frequently asked questions

What does Evaluation metric example: String similarity do?

AI evaluation in n8n This is a template for n8n's evaluation feature. Evaluation is a technique for getting confidence that your AI workflow ...

What do I need before importing this workflow?

Review the workflow JSON, configure any required credentials in n8n, and test the automation in a safe workspace before using it in production.

Can I customize this workflow?

Yes. Use the block-by-block analysis and the downloadable JSON to inspect each node, then adjust credentials, prompts, schedules, filters, or destinations for your Engineering, AI Summarization use case.