How to Migrate from Fauna to MongoDB

How to fix it

Try these in order — the most common fix is first.

1. 1. Import collections

   Copy steps
   1. Convert Fauna-specific types (refs, time values) to plain strings or ObjectIds in a script
   2. Run mongoimport per collection
   3. Compare counts with the source
   Did this fix it? Yes No

2. 2. Rebuild indexes and queries

   Copy steps
   1. Create indexes for the fields you queried
   2. Replace FQL joins with $lookup or denormalized fields
   Did this fix it? Yes No

Symptoms

You want to keep a document model after Fauna.

Why it happens

• Fauna refs and timestamps are exported in Fauna-specific formats
• Joins relied on FQL
• Indexes are not carried over

This guide also covers

• fauna to mongodb
• migrate faunadb to mongodb
• fauna alternative mongodb

Other Fauna errors

• Is Fauna Shutting Down? What Happened and What to Do
• How to Export Your Data from Fauna (Before and After Shutdown)
• How to Migrate from Fauna to Postgres
• Fauna Not Working: Connection Refused or Request Failed
• Is Fauna Open Source? Can You Self-Host It?
• Fauna Billing After Shutdown: Charges, Refunds and Cancel
• Converting FQL Queries to SQL After Fauna
• Fauna GraphQL and REST API Not Responding After Shutdown