SwiftTune vs Braintrust
Braintrust scores what you built. SwiftTune builds it and scores it.
Braintrust is an evaluation platform you point at an application you already wrote and host. SwiftTune is the platform that composes the application, runs it on your Cloudflare account, and reports on the flow it just served. If evaluation is the whole job, they are deeper at it than we are.
Braintrust: An evaluation and observability platform for AI applications: datasets, experiments, scorers, logging and human review, driven from their SDKs.
Free tier, no card. Bring your own Cloudflare account.
SwiftTune and Braintrust, question by question
The same nine questions asked of both products. Three of the answers in our column are not a yes, and they are not a yes on any of these pages.
| Capability | SwiftTune | Braintrust |
|---|---|---|
| Visual builder that produces the deployed application | Yes Blocks on a canvas. The graph the canvas validates is the graph the runtime versions and deploys. | No A playground for comparing prompt versions side by side, not a canvas that produces the deployed application. |
| Runs the application itself | Yes The platform runs the flow, so the thing reporting on a deployment is the thing that served it. | Partly Prompts, scorers and tools run on their platform. The application around them is still yours to write and host. |
| Deploys into a Cloudflare account you own | Yes Flows deploy into the Cloudflare account you bring. Infrastructure stays billed to you at Cloudflare’s rates. | No A hosted platform, with a hybrid deployment for enterprise accounts. Not a Cloudflare deployment target. |
| Prompt management for people who do not deploy | Partly A prompt is a field on a block, versioned with the flow that ships it. There is no approval queue for the wording on its own. | Partly Prompts are versioned and compared side by side in the playground. The workflow is built around the team holding the SDK. |
| Evaluation of prompts and outputs | Yes Evals clusters production traffic, builds eval sets from it, and scores a version against the one before it. | Yes The core of the product: datasets, experiments, custom scorers and human review, built for the job. |
| Retrieval quality monitoring | Yes Retrieval Monitor reports recall@K, precision, MRR and NDCG per query cluster, continuously. | Partly Retrieval is scored by writing a scorer for it. There is no recall or drift surface of its own. |
| Cost attribution by feature, user and prompt | Yes Cost Attribution breaks spend down by feature, user, prompt template and provider. | Partly Token counts and cost land on logged spans. Grouping them by feature or prompt template is a query you write. |
| Open source or self-hostable | No Not open source, and there is no build to run on your own hardware. Your flows run on your Cloudflare account; the control plane is ours. | Partly The scoring libraries are open source. The platform is commercial, self-hosted on enterprise terms. |
| General-purpose connectors beyond AI services | Partly Cloudflare services, any MCP server and plain HTTP. Not a catalogue of SaaS connectors. | No Not a workflow tool. It instruments the application you already wrote, in whatever it is written in. |
The Braintrust column was read from their public documentation on 4 September 2026. Both products change. Check it against the source before you decide. Braintrust documentation.
Where Braintrust is better
Three things they do that we do not, or do not do as well. If one of them is the reason you are here, stay where you are.
Their evaluation model is deeper than ours
Datasets, experiments, custom scorers, human review queues and a side-by-side view built for comparing runs. Evals here clusters live traffic and diffs versions; it does not give you a scoring workbench.
It instruments a stack we do not run
Their SDKs attach to whatever you already have — any framework, any cloud, any model. SwiftTune reports on flows it deployed and on nothing else, which is a real limit if the application is staying where it is.
Adopting it changes nothing about your architecture
You add a call and keep every deployment decision you have already made. Moving to SwiftTune means the flow gets rebuilt on a canvas, which is a bigger ask than an SDK.
Stay on Braintrust if evaluation is the work and the application is already built and hosted the way you want it.
Where SwiftTune is better
The other half, held to the same standard: each one is a capability in the product today, not a line on a roadmap.
The thing measuring the flow is the thing running it
No export step and no second vendor holding half the picture. A trace, its cost and the version that produced it come from the deployment that served the request.
Retrieval and spend have surfaces, not scorers
Recall@K, precision, MRR and NDCG per query cluster, and spend broken down by feature, user and prompt template. Neither is something you write first.
The application is a graph you can read
Typed ports, cycle detection and versioning on the canvas, deployed to your own Cloudflare account. The evaluation platform stops being a thing you also have to buy.
Come here if you are still assembling the application and would rather not run an eval vendor beside it.
Moving from Braintrust
Nothing has to be switched off on day one. Braintrust watches an application it does not run, so the two can observe the same traffic while you decide.
What does not come across: custom scorers written against their SDK, and any human review queue your team works out of. Both have to be rebuilt, and Evals does not have a review workbench.
Run the flow and the evaluation in one place
Rebuild one flow on the free tier and put it beside what you have. Nothing to switch off, and nothing to sign.
Free tier, no card. Bring your own Cloudflare account.