Best Fine Tuning Companies

Vendor profileChecked Nov 8, 2026

CoreWeave Serverless Training (incl. OpenPipe)

CoreWeave, Inc. · docs.coreweave.com · Last checked:

  • Managed fine-tuning API
  • Reinforcement fine-tuning
  • Serverless training

Company status

Active. CoreWeave is publicly listed on Nasdaq (CRWV). CoreWeave announced a definitive agreement to acquire OpenPipe on September 3, 2025; the OpenPipe platform states it has migrated to Weights & Biases and CoreWeave.

Sources 1, 2, 3, 4, 5, 6 · checked 2026-11-08

Capabilities

  • Serverless RL: reinforcement learning with your own reward function, for multi-turn agentic tasks
  • Serverless SFT: supervised fine-tuning on input/output examples (public preview)
  • Training produces LoRA adapters stored as Weights & Biases Artifacts; adapters can be saved locally
  • Every trained checkpoint is hosted on CoreWeave Serverless Inference
  • Works with the open-source ART framework from OpenPipe

Sources 1, 2, 3, 4, 5, 6 · checked 2026-11-08

Who it tends to fit

  • Teams training agents with reinforcement learning
  • Teams already using Weights & Biases for experiment tracking

Sources 1, 2, 3, 4, 5, 6 · checked 2026-11-08

Pricing

Contact vendor (training billed per GPU-hour of active training time; rate listed on CoreWeave's post-training pricing page, not confirmed when checked)

Sources 1, 2, 3, 4, 5, 6 · checked 2026-11-08

Published certifications

  • SOC 2 (listed in compliance programs; reports via trust portal)
  • ISO 27001 (listed in compliance programs)
  • ISO 27017
  • ISO 27018

Listed as stated by the vendor. Scope can differ by product or subsidiary; request current reports.

Sources 1, 2, 3, 4, 5, 6 · checked 2026-11-08

Limitations to check

  • Serverless SFT is in public preview
  • LoRA rank and alpha are fixed per base model and cannot be set
  • Training sequence limit of 32,768 tokens for most models
  • Audit reports are gated behind the trust portal

Sources 1, 2, 3, 4, 5, 6 · checked 2026-11-08

Sources

  1. Serverless Training: Serverless RL and Serverless SFT; LoRA adapters stored as W&B Artifacts; checkpoints hosted on Serverless Inferencedocs.coreweave.com/trainingChecked 2026-11-08
  2. Serverless SFT is in public preview; LoRA rank/alpha fixed per base modeldocs.coreweave.com/products/post-training/serverless-training/sftChecked 2026-11-08
  3. Billed per GPU-hour prorated by active training time; 32,768-token sequence limit; 5 GB free storagedocs.coreweave.com/products/post-training/serverless-training/usage-limitsChecked 2026-11-08
  4. Sept 3, 2025 definitive agreement to acquire OpenPipe; CoreWeave listed on Nasdaq (CRWV) in March 2025www.coreweave.com/news/coreweave-to-acquire-openpipe-leader-in-reinforcement-learningChecked 2026-11-08
  5. OpenPipe site states the platform has migrated to Weights & Biases and CoreWeaveopenpipe.ai/Checked 2026-11-08
  6. Compliance programs: SOC 2, ISO 27001, ISO 27017, ISO 27018docs.coreweave.com/security/trust-compliance/compliance-programsChecked 2026-11-08

Report a correction: [email protected]. Facts are re-checked at least every 90 days.