MongoDB Skill

Query MongoDB databases using the Atlas Data API (curl) or mongosh fallback.

Quick Start

# Find documents via Atlas Data API
curl -s -X POST "$MONGODB_DATA_API_URL/action/find" \
  -H "api-key: $MONGODB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "dataSource": "'"$MONGODB_CLUSTER"'",
    "database": "'"$MONGODB_DATABASE"'",
    "collection": "users",
    "filter": {},
    "limit": 10
  }'

Prerequisites

Option A: Atlas Data API (Recommended — no CLI install needed)

Variable	Description	Example
MONGODB_DATA_API_URL	Atlas Data API endpoint	https://data.mongodb-api.com/app/data-xxxxx/endpoint/data/v1
MONGODB_API_KEY	Atlas Data API key	abc123...
MONGODB_CLUSTER	Cluster name	Cluster0
MONGODB_DATABASE	Default database name	myapp

Option B: Connection String (for mongosh fallback)

Variable	Description	Example
MONGODB_URL	Full connection string	mongodb+srv://user:pass@cluster.mongodb.net/mydb

Enable Atlas Data API

1. Go to MongoDB Atlas — App Services — Create Application
2. Enable Data API — Choose your cluster
3. Create an API key
4. Copy the endpoint URL

Verify Setup

curl -s -X POST "$MONGODB_DATA_API_URL/action/find" \
  -H "api-key: $MONGODB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "dataSource": "'"$MONGODB_CLUSTER"'",
    "database": "'"$MONGODB_DATABASE"'",
    "collection": "users",
    "limit": 1
  }' | jq .

Data API Recipes

Find Documents

curl -s -X POST "$MONGODB_DATA_API_URL/action/find" \
  -H "api-key: $MONGODB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "dataSource": "'"$MONGODB_CLUSTER"'",
    "database": "'"$MONGODB_DATABASE"'",
    "collection": "users",
    "filter": {"status": "active"},
    "sort": {"created_at": -1},
    "limit": 20
  }' | jq '.documents'

Find One Document

curl -s -X POST "$MONGODB_DATA_API_URL/action/findOne" \
  -H "api-key: $MONGODB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "dataSource": "'"$MONGODB_CLUSTER"'",
    "database": "'"$MONGODB_DATABASE"'",
    "collection": "users",
    "filter": {"email": "john@example.com"}
  }' | jq '.document'

Insert One Document

curl -s -X POST "$MONGODB_DATA_API_URL/action/insertOne" \
  -H "api-key: $MONGODB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "dataSource": "'"$MONGODB_CLUSTER"'",
    "database": "'"$MONGODB_DATABASE"'",
    "collection": "users",
    "document": {
      "name": "John",
      "email": "john@example.com",
      "created_at": {"$date": "'"$(date -u +%Y-%m-%dT%H:%M:%SZ)"'"}
    }
  }' | jq .

Update One Document

curl -s -X POST "$MONGODB_DATA_API_URL/action/updateOne" \
  -H "api-key: $MONGODB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "dataSource": "'"$MONGODB_CLUSTER"'",
    "database": "'"$MONGODB_DATABASE"'",
    "collection": "users",
    "filter": {"email": "john@example.com"},
    "update": {"$set": {"status": "active"}}
  }' | jq .

Delete One Document

curl -s -X POST "$MONGODB_DATA_API_URL/action/deleteOne" \
  -H "api-key: $MONGODB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "dataSource": "'"$MONGODB_CLUSTER"'",
    "database": "'"$MONGODB_DATABASE"'",
    "collection": "users",
    "filter": {"email": "john@example.com"}
  }' | jq .

Aggregate Pipeline

curl -s -X POST "$MONGODB_DATA_API_URL/action/aggregate" \
  -H "api-key: $MONGODB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "dataSource": "'"$MONGODB_CLUSTER"'",
    "database": "'"$MONGODB_DATABASE"'",
    "collection": "orders",
    "pipeline": [
      {"$match": {"status": "completed"}},
      {"$group": {"_id": "$customer_id", "total": {"$sum": "$amount"}, "count": {"$sum": 1}}},
      {"$sort": {"total": -1}},
      {"$limit": 10}
    ]
  }' | jq '.documents'

mongosh Fallback

If you need interactive shell access or the Data API isn't available:

# Install mongosh on the fly (not pre-installed to save ~100MB)
npx mongosh "$MONGODB_URL" --eval "db.users.find().limit(10).toArray()"

Common mongosh Commands

# List databases
npx mongosh "$MONGODB_URL" --eval "show dbs"

# List collections
npx mongosh "$MONGODB_URL" --eval "show collections"

# Count documents
npx mongosh "$MONGODB_URL" --eval "db.users.countDocuments()"

# Find with filter
npx mongosh "$MONGODB_URL" --eval "db.users.find({status: 'active'}).limit(10).toArray()"

Error Handling

Error	Cause	Solution
401 Unauthorized	Invalid API key	Check MONGODB_API_KEY
no app found	Wrong Data API URL	Verify MONGODB_DATA_API_URL in Atlas
no rule exists	Collection not allowed	Enable collection in Atlas Data API settings
cannot find dataSource	Wrong cluster name	Check MONGODB_CLUSTER matches Atlas
connection refused (mongosh)	Wrong URL	Verify MONGODB_URL connection string

Tips

• Use Data API for simple CRUD — no install needed, just curl
• Use mongosh for complex work — aggregations, admin tasks, interactive exploration
• Always use jq to format JSON responses from the Data API
• Use $date wrapper for date fields in Data API requests
• Projection — add "projection": {"_id": 0, "name": 1, "email": 1} to limit returned fields
• Atlas Data API has rate limits — 10,000 requests/minute per project