We are fully open-source (AGPLv3) with just one ee plugin for syncing the cache of the workers at large scale (more on that below). You can deploy it on a small ec2 instance with our docker-compose or on very large clusters with our helm charts: https://docs.windmill.dev/docs/advanced/self_host
We are an onion of 3 layers, which are usually separated verticals and the closest services we replace in each vertical are: Lambda + n8n/temporal + Retool:
- Workers implemented in Rust that can run any scripts from source in python/typescript(deno)/go/bash. They are extremely efficient, with most typescript scripts being able to run in 40ms e2e. This can be seen as a self-hosted lambda except it works very differently. Lambdas spawn microvms using firecracker and launch http servers within those micro-vms. We run the scripts bare (with isolation using nsjail on our multi-tenant instance) but cache very aggressively the dependencies. For instance, in python we analyze the dependencies using the AST: https://github.com/windmill-labs/windmill/blob/main/backend/..., infer the dependencies from there, have them go through pip-compile to generate a lockfile (and cache the result), then create a pathset similar to how virtualenv behave with the version of each dependency locked. For typescript, we leverage the very well made immutable deno cache. The cache works well but if you scale your cluster to more than 10 workers, the likelihood of having your worker see dependencies for the first time increase, which is why we reimplemented a pip scheme backed by s3 that is extremely fast (we do not compress, just tar individual wheels and s3 is very fast on local networks). For all the supported languages, we parse the signatures of the main function to infer the corresponding json schema of the payload to trigger them, and from that jsonschema we can then generate automatically the UI and infer the input shape required in the flows for that particular step.
- A workflow engine re-implemented from scratch which can be seen as a distributed FSM and whose state is stored in postgresql and every transition done through postgres transactions. Every worker is picking a job and progressing the fsm at completion. The full spec is at: https://docs.windmill.dev/docs/openflow. We support branches, for loop, suspend/sleep, approval steps, sharing the same folder between steps and everything you would expect from a temporal like engine (retries, error handlers).
- A dashboard/app builder that is very similar to Retool but much faster because it's implemented in Svelte and which can also run python scripts directly leveraging the 1st layer. We also support full react apps: https://github.com/windmill-labs/windmill-react-template
We have a CLI that allows you to sync from github directly: https://github.com/windmill-labs/windmill-sync-example or your local filesystem. Our scripts are absolutely normal scripts so there is no lock-in, and they are executable locally https://docs.windmill.dev/docs/advanced/local_development so you do not have to use our webeditor if you do not want to but our editor supports pyright and deno lsp through our dedicated backend communicating to monaco using websockets.
We also support worker groups to run some jobs on hardware accelerated machines (GPU) and a lot of other features (oauth syncing of the resources, schedules, granular permissioning, groups and folders).
Every script/flow deployed has a dedicated webhook endpoint to run synchronously and asynchronously. Scripts are never overwritten, they keep a lineage of hash for each version and have per-hash dedicated webhook to ensure their behavior never change.
We also have a hub for sharing re-usable scripts https://hub.windmill.dev to be used in flows to have some of the same convenience you can find in Pipedream or Zapier.
Our closest alternative would be Airplane.dev, but they're not open-source, not self-hostable air-gapped, less performant, less-featured and much more expensive. You can self-host us fully free.
We are used in production at scale in clusters of 50 nodes+ and thanks to the reliability of Rust and Postgresql have had no downtime to report.
I'm a solo founder, YC S22. The MVP got some attention at the very beginning: https://news.ycombinator.com/item?id=31272793 but was very bare. Now we're ready to bring this to the next level and enable all engineers to spend more time building and less time reinventing the wheel thanks to it :)
One suggestion: I think you could do improve the docs by (a) providing a direct comparison to Airplane and (b) providing more code-oriented documentation.
Most of you docs highlight the web editor which, frankly, I have little interest in. I want to write my scripts and views in my IDE and store them in GitHub. This is something Airplane really nails: their docs are clearly about how to use this as a developer. Compare your flows quick start [0] with their tasks quick start [1] and it really feels like Airplane is more suited to a developer audience. I'm worried I will be locked into static control flow with yours, whereas Airplane makes it clear I can do ~any code I want, as long as it runs in Temporal.
Of course, totally fair if you are trying to target more no-code use cases.
[0]: https://docs.windmill.dev/docs/getting_started/flows_quickst... [1]: https://docs.airplane.dev/getting-started/orchestration
For the temporal thing, that's absolutely fair and completely understand the worry but since most workflows are about the steps and not the glue between them, you will be able to reuse most of your code. However, temporal is quite an heavy format for writing workflows so of course it will still be a bit of work.
Our views support our retool like builder but also full react apps, or svelte, or vue, or anything that can compile to an iife. The example provided above can be iterated on with just a simple 'npm run dev': https://github.com/windmill-labs/windmill-react-template