/Tech5h ago

Castform launches an open preview of its platform to automate custom open-weights model training on proprietary data

The platform converts agent traces into structured training sets.

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Original post
Matt Henderson@matthen2#994inTech

Training custom models for specific tasks is such a super power. Own your model, the data going into it - backpropagate gradients- and enjoy reliable outputs and crazy fast latency. Castform is making that easy for everyone 👀

girish@googrish

“don’t train your own model” is common ai advice. it's wrong. your token bill's the proof.

today, we’re excited to launch castform into open preview. castform is the easiest way for you to train your own model, on your own data.

open-weights models are performant and much cheaper. when trained on your task & proprietary data, they beat closed models. the thing standing between you and that was weeks of plumbing & years of ml expertise.

with castform, model training is as simple as prompt engineering. @castformai

bring your agent traces or raw corpora. castform turns it into training data, picks the right algorithmic recipes, manages gpus, and gives you an ide to watch and chat with your model as it learns.

see what you can build with castform👇

9:42 AM · Jun 11, 2026 · 1.8K Views
Sentiment

Many users praise Castform's open preview launch for simplified custom AI model training due to its engaging ad and video, while some object to the Castie mascot's uncanny design.

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57 comments with sentiment.
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VIEWS1.2KBOOKMARKS3LIKES15
girish@googrish

1/4 train your first model today. new users get $50 in free credits 🙂https://castform.dev/blog/beta-launch/

5hViews 1.2KLikes 15Bookmarks 3
RETWEETS56
girish@googrish

“don’t train your own model” is common ai advice. it's wrong. your token bill's the proof.

today, we’re excited to launch castform into open preview. castform is the easiest way for you to train your own model, on your own data.

open-weights models are performant and much cheaper. when trained on your task & proprietary data, they beat closed models. the thing standing between you and that was weeks of plumbing & years of ml expertise.

with castform, model training is as simple as prompt engineering. @castformai

bring your agent traces or raw corpora. castform turns it into training data, picks the right algorithmic recipes, manages gpus, and gives you an ide to watch and chat with your model as it learns.

see what you can build with castform👇

5hViews 118.1KLikes 960Bookmarks 1K
REPLIES4
Dan 🪼@dah_uk

@googrish Signing in with Google or DH appears to be broken

4hViews 132Likes 1
girish@googrish

2/4 you can train a model on your production agent traces so the model can learn from mistakes it made in product with castform.

5hViews 908Likes 15Bookmarks 1
girish@googrish

@vatslgoswami currently, we support text models only -> multimodal coming by end of the summer :)

on data, depends on the task but have seen pretty good results from 100s to 1000s of samples

4hViews 283Likes 5Bookmarks 1
girish@googrish

3/4 you can train an agent to do accurate and fast citation-grounded search over documentation

5hViews 685Likes 12
girish@googrish

4/4 you can train a model to red-team & find bugs with castform

5hViews 736Likes 11
girish@googrish

train your first model today at http://app.castform.com

5hViews 646Likes 9
chloe@barofclo

@googrish this is so cool you guys. making the model layer more accessible 🌱

4hViews 182Likes 2
Joel Lee@__joellee__

@googrish Congrats! What’s the next big feature the team has lined up?

4hViews 110Likes 2
Ying Hang@YingHang7

@dah_uk @googrish We just tested the flow and it seems to be working again now. Might have been some transient error - do you mind trying again?

3hViews 52Likes 1
Tanner Le@shartscut

@googrish This is SICK

5hViews 195Likes 4
Cassie Ton@thitrangmam

@googrish Please make Castie merch!!!

5hViews 125Likes 3
Andy Berman@berman66

@googrish Can’t wait to try it

4hViews 123Likes 3
Vatsl Goswami@vatslgoswami

@googrish can these models perform complex tasks like image segmentation from limited data? what kind and how much data would one need for a self-trained model to be able to compete with the foundational ones?

4hViews 304Likes 2
chetan mishra@chetanfs

@googrish Product and glasses are dope

5hViews 175Likes 2

@googrish congrats on the launch!

5hViews 141Likes 2

@googrish Congrats on the launch! How well does this work for voice?

4hViews 122Likes 2
Alex Klarfeld@AlexKlarfeld

@googrish This is awesome - congrats Girish!

4hViews 97Likes 2
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