Fraud & AML monitoring you run yourself/Built in the UK
We're building open-source financial infrastructure
Self-hosted engines, models and adapters for fintechs and payment rails. Your data never leaves your infrastructure.
$docker run -p 8080:8080 -e OSPREY_ADMIN_TOKEN=change-me ghcr.io/opensource-finance/osprey:latestOr hand it to your agent:
- 1
- binary, written in Go
- 60s
- from download to first evaluation
- CEL
- sandboxed rule engine
- 0
- per-seat or per-transaction fees
01Projects
- OspreyReal-time transaction monitoring engine. CEL rules, FATF typologies.Live
- NarratorFine-tuned model for CEL rule authoring and SAR narratives.v0.1
- StudioVisual rule builder and typology editor.Building
- CasesAlert triage and investigation workspace.Roadmap
- AdaptersPlanned ISO 20022, gRPC and GraphQL ingestion. JSON over REST today.Roadmap
02Compare
| Osprey | Tazama | Enterprise SaaS | |
|---|---|---|---|
| Deploy | 60 seconds | Weeks (Kubernetes) | API or sales cycle |
| Architecture | Single binary | 7+ microservices | SaaS only |
| Team | 1 developer | Platform team | Eng + compliance |
| Cost | Free, Apache 2.0 | High ops cost | $30k–$740k / yr |
| Data | Yours | Yours | Vendor-held |
Enterprise SaaS: Sardine, Unit21, ComplyAdvantage.
03About
Small payment firms need real transaction monitoring, but most monitoring platforms need a platform team to run them. Osprey is for the smaller team: one Go binary that one engineer can run, with rules an auditor can read. I have built transaction monitoring before, as one of the founding engineers on Tazama. opensource.finance is based in the United Kingdom.
Joseph Goksu, founder
05Sponsor
Osprey is free to run and built in the open. Sponsorship pays for maintainer time, releases and documentation, so fintechs and payment networks get monitoring they can inspect instead of rent.
06FAQ
What is opensource.finance?
opensource.finance is an open-source project building self-hosted infrastructure for fraud and AML transaction monitoring. Instead of renting a closed vendor system, fintechs and payment companies run the engine on their own servers and can read every rule it applies. Code is Apache 2.0; the project is published by Reaktif LLC.
What projects does opensource.finance include?
Osprey (live, v0.1.0): the transaction monitoring engine. Osprey Narrator (v0.1): a fine-tuned model that drafts CEL rules and SAR narratives, on Ollama and HuggingFace. Studio (building): a visual rule builder. Cases (roadmap): an alert triage workspace. Adapters (roadmap): ISO 20022, gRPC and GraphQL ingestion; Osprey accepts JSON over REST today.
What is Osprey?
Osprey is one Go binary that scores each transaction against CEL rules and returns an alert decision, a risk score and the reasons. It ships with 12 FATF-inspired starter rules, and a rule change is live without a restart. Measured on a laptop with v0.1.0: about 1 ms median per request, and 380 evaluations per second at p99 66 ms with 10 concurrent clients.
How does Osprey compare to Tazama and enterprise SaaS vendors?
Tazama, an open-source platform Osprey's founder worked on, runs as 7+ microservices on Kubernetes and needs a platform team. Osprey is one binary that one engineer can run. Enterprise vendors such as Sardine, Unit21 and ComplyAdvantage charge roughly $30,000 to $740,000+ a year and hold your data; Osprey is Apache 2.0 and runs inside your own infrastructure.
What does Osprey Narrator do?
Osprey Narrator is a fine-tuned language model (v0.1). It drafts CEL rules from a plain-English description of a fraud pattern, and drafts SAR-style narratives from an Osprey alert. It runs locally through Ollama or HuggingFace. Review its output before you use it.
Is opensource.finance free and open source?
Yes. The engine is Apache 2.0 and the Narrator model is published openly on HuggingFace and Ollama. You run them on your own hardware or cloud with no per-seat or per-transaction fees, and transaction data never leaves your infrastructure.