What is the Cosmos DB free tier and what does it include?

The Cosmos DB free tier is a permanent (not time-limited) offering where every Azure account can have one Cosmos DB account with a perpetual free allocation, making it suitable for prototyping, side projects, and learning without ongoing costs.

The free tier allocation includes:

• 1,000 RU/s provisioned throughput — always free, every month, no expiration
• 25 GB of storage — always free, every month

This is enough for a small application with moderate load. For context: 1,000 RU/s can handle approximately 1,000 point reads per second, or roughly 200 writes per second for 1 KB documents. 25 GB covers millions of typical user profile documents.

Important constraints and conditions:

• Only one free tier account per Azure subscription. You cannot have multiple free tier accounts in the same subscription.
• Free tier must be selected at account creation — it cannot be applied to an existing paid account.
• Resources beyond the free allocation (above 1,000 RU/s or 25 GB) are billed at standard rates. For example, if you provision 4,000 RU/s, you pay for 3,000 RU/s and the first 1,000 are free.
• All APIs are eligible for the free tier — NoSQL, MongoDB, Cassandra, Gremlin, and Table.
• Multi-region replication multiplies throughput costs as usual, even for the portion covered by free tier.

The free tier is different from the 30-day Azure free trial credits. Free tier credits are perpetual and apply to the Cosmos DB account specifically, continuing even after the trial period ends — as long as you stay within the 1,000 RU/s and 25 GB allocations, you pay nothing.