n8n-nodes-atomic-mongo-counter

An n8n community node for generating atomic, incremental integer counters using MongoDB.

Features

• Uses MongoDB $inc for atomic counter updates
• Safe for concurrent workflow executions
• Reuses n8n-managed MongoDB credentials
• Configurable collection
• Configurable lookup field and value
• Configurable counter field
• Configurable increment amount
• Configurable output field
• Optional upsert support

Example

Counter document:

{
  "counter_name": "package_id_counter",
  "seq": 1000
}

Node configuration:

Collection: counters
Lookup Field: counter_name
Lookup Value: package_id_counter
Counter Field: seq
Increment By: 1
Output Field: package_id
Upsert: false

Output:

{
  "package_id": 1001
}

MongoDB Index Recommendation

For the counter collection:

db.counters.createIndex(
  { counter_name: 1 },
  { unique: true }
)

For the destination collection:

db.forms.createIndex(
  { package_id: 1 },
  { unique: true }
)

Credentials

This node uses the standard n8n MongoDB credential type.

Credentials are selected from the n8n UI and are not hardcoded in the workflow or node source.

Installation

Install from n8n Community Nodes using:

n8n-nodes-atomic-mongo-counter

License

MIT