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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
https://akaunting.com/ is probably pretty close to freshbooks. It's open source and can be self hosted. There are also more alternatives if you check out alternativto or https://github.com/awesome-selfhosted/awesome-selfhosted#money-budgeting--management
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