Floci emerges as a free, open-source alternative to LocalStack after the latter's community edition sunset in March 2026. Named after floccus cloud formations that resemble popcorn, Floci offers a no-strings-attached local AWS emulator that requires no account, features no feature gates, and imposes no CI restrictions. Just docker compose up and you're running.

Unlike LocalStack Community, which now requires auth tokens and dropped CI support while freezing security updates, Floci provides unlimited CI/CD support, ongoing security updates, and startup times of approximately 24 milliseconds compared to LocalStack's 3.3 seconds. The memory footprint is dramatically smaller at roughly 13 MiB versus 143 MiB, and the Docker image size shrinks from 1.0 GB to just 90 MB. Floci supports 20+ AWS services with 408/408 SDK tests passing and maintains an MIT license for unrestricted use.

Developers can point existing AWS SDKs at http://localhost:4566 with no other changes needed. The tool supports API Gateway v2, Cognito, ElastiCache with IAM auth, RDS for PostgreSQL and MySQL, S3 Object Lock, DynamoDB Streams, IAM, STS, Kinesis, and KMS. Native binary builds are available at approximately 40 MB. Configuration is handled through environment variables with sensible defaults, making it simple to integrate into existing development workflows.