Modal vs Stability AI: Token Pricing, Speed & Intelligence
Full comparison of Modal and Stability AI — live token pricing, latency, throughput, context window, strengths, weaknesses, and best use cases. Rates sourced from public APIs — verify before use.
Modal
Managed inference API — 10 shared-endpoint models with per-token pricing
Modal Shared Endpoints serve a fixed catalog of models from Modal-managed pools. Modal manages the hardware and autoscaling, and usage is billed per token. Shared Endpoints have model-specific concurrency limits on concurrent in-flight requests. Prices are published rates from modal.com/docs/guide/supported-models.md, re-read 2026-10-31.
Stability AI
Stable Diffusion 3.5 Large and Stable Image Ultra — open-weight image generation
Stability AI is the creator of Stable Diffusion, the most widely deployed open-weight image generation model family. The 2026 API offers Stable Diffusion 3.5 Large (highest quality), SD 3.5 Medium (balanced), and Stable Image Ultra for photorealistic output. All SD 3.5 models are open-weight and available for self-hosting. Stability AI also offers Stable Video Diffusion for short video generation.
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Live token pricing
Strengths and weaknesses
Modal
Stability AI
Key differentiators
Modal Shared Endpoints provide managed per-token inference on a fixed 10-model catalog with published cached-input pricing and no infrastructure to manage.
Stable Diffusion 3.5 models are open-weight and self-hostable — enabling the largest fine-tuning and LoRA ecosystem of any image generation model family, with full control over the generation pipeline.
Frequently asked questions
Modal FAQs
What models does Modal offer on Shared Endpoints?
Modal Shared Endpoints currently serve 10 models: GLM 5.3 Flash NVFP4, DeepSeek V4.1 Flash 1017, DeepSeek V4.1 Flash, GLM 5.3 Flash, Muse Spark Open, GLM 5.3, Inkling NVFP4, Qwen3.8-Max, Qwen3.8-Max VL, and Kimi K3. Use the model table above for per-model pricing and capability details. Source: Modal's published Shared Endpoints catalog, re-read 2026-10-31.
How much does Modal charge per 1M tokens?
Modal Shared Endpoints input prices range from $0.15/1M (GLM 5.3 Flash NVFP4) to $3.00/1M (Kimi K3). All models include cached-input pricing. See the model table for full per-model rates.
Does Modal offer prompt caching?
Yes. All 10 models in the Modal Shared Endpoints catalog have published cached-input pricing, ranging from $0.005/1M (DeepSeek V4.1 Flash 1017) to $0.30/1M (Kimi K3). Depending on the model, the cached-input rate is 77.5% to 98% below the standard input rate. Source: Modal's published Shared Endpoints rates, re-read 2026-10-31.
Stability AI FAQs
What is Stable Diffusion 3.5?
Stable Diffusion 3.5 is Stability AI's latest generation of open-weight text-to-image models. SD 3.5 Large offers the highest quality; SD 3.5 Medium is a balanced option for production use. Both are available for self-hosting.
How does Stability AI compare to FLUX?
FLUX 1.1 Pro generally outperforms SD 3.5 on photorealism and prompt adherence benchmarks. However, SD 3.5 has a much larger community ecosystem of fine-tuned variants and LoRAs, making it more flexible for specialised use cases.
Can I self-host Stable Diffusion 3.5?
Yes. SD 3.5 Large and Medium weights are publicly available under the Stability AI Community License. You can run them on any GPU with sufficient VRAM — SD 3.5 Medium requires ~8GB VRAM; SD 3.5 Large requires ~24GB.
Provider resources
Modal — Managed inference API — 10 shared-endpoint models with per-token pricing
Modal Shared Endpoints serve a fixed catalog of models from Modal-managed pools. Modal manages the hardware and autoscaling, and usage is billed per token. Shared Endpoints have model-specific concurrency limits on concurrent in-flight requests. Prices are published rates from modal.com/docs/guide/supported-models.md, re-read 2026-10-31.
Modal Shared Endpoints provide managed per-token inference on a fixed 10-model catalog with published cached-input pricing and no infrastructure to manage.
Stability AI — Stable Diffusion 3.5 Large and Stable Image Ultra — open-weight image generation
Stability AI is the creator of Stable Diffusion, the most widely deployed open-weight image generation model family. The 2026 API offers Stable Diffusion 3.5 Large (highest quality), SD 3.5 Medium (balanced), and Stable Image Ultra for photorealistic output. All SD 3.5 models are open-weight and available for self-hosting. Stability AI also offers Stable Video Diffusion for short video generation.
Stable Diffusion 3.5 models are open-weight and self-hostable — enabling the largest fine-tuning and LoRA ecosystem of any image generation model family, with full control over the generation pipeline.
Key strengths compared
Modal
- Managed hardware and autoscaling — no infrastructure to operate
- Published per-token rates including cached-input pricing
- OpenAI-style per-token billing across all 10 models
- Small fixed catalog of 10 models
- Model-specific concurrency limits on shared pools
Stability AI
- Open-weight SD 3.5 models — self-host on any GPU cloud
- Largest community ecosystem of fine-tuned variants and LoRAs
- Stable Image Ultra for photorealistic output
- Image quality trails FLUX 1.1 Pro and Midjourney on photorealism benchmarks
- Company has faced financial challenges and leadership changes
Key weaknesses compared
Modal
- Small fixed catalog of 10 models
- Model-specific concurrency limits on shared pools
- Prices are published rates re-read 2026-10-31, not continuously collected
Stability AI
- Image quality trails FLUX 1.1 Pro and Midjourney on photorealism benchmarks
- Company has faced financial challenges and leadership changes
- SD 3.5 adoption slower than FLUX in the community
Provider category context
Modal is a inference api. Stability AI is a frontier lab, founded in 2020. Modal as an inference API provider hosts open-weight models — typically offering lower prices for equivalent capability tiers. Stability AI as a frontier lab trains and serves proprietary models with capabilities not available elsewhere.
How to choose between them
Choose Modal if you need managed hardware and autoscaling — no infrastructure to operate. Choose Stability AI if you need open-weight sd 3.5 models — self-host on any gpu cloud. For high-volume production workloads, run a cost comparison using the token pricing table above with your actual prompt/completion token ratio — the cheapest provider depends heavily on your input-to-output token ratio.