# Modal vs Union.ai

Modal records 1,196,021 monthly visits with +30.2% month-over-month growth and Freemium, Contact for Pricing pricing. Union.ai records 17,787 monthly visits with -28.4% growth and Freemium, Contact for Pricing pricing.

| Metric | [Modal](https://openaitools.app/tool/modal-com) | [Union.ai](https://openaitools.app/tool/union-cloud) |
| :--- | :--- | :--- |
| Website URL | https://modal.com | https://union.ai |
| Categories | AI Developer Tools, AI API, Large Language Models (LLMs), AI Models | AI Developer Tools, AI Workflow, Large Language Models (LLMs), AI Models |
| Pricing Model | Freemium, Contact for Pricing | Freemium, Contact for Pricing |
| Monthly Visits | 1,196,021 | 17,787 |
| MoM Growth Rate | +30.2% | -28.4% |
| Primary Market | United States | United States |
| Direct Visits | 845,636 | 7,040 |
| Review Score | 4.8 | 4.4 |
| Saved Count | 3 | 0 |
| Supported Platforms | Website | Website |

## Modal

Modal provides cloud infrastructure aimed squarely at AI and data teams. The core idea is that developers write ordinary Python, decorate functions or define container images, and Modal takes care of the underlying compute: scheduling containers, attaching GPUs, autoscaling from zero and back, and exposing endpoints over HTTPS. Infrastructure concerns like networking, storage, and capacity management are abstracted away, so a workload that runs on a laptop can run the same way across a fleet.

The platform is organised around a few primitives. Functions handle serverless compute and can fan out across thousands of GPUs for parallel or batch work. Sandboxes provide isolated environments for coding agents, reinforcement learning rollouts, and other untrusted code, with sub-second start times and support for very high concurrency. Training covers fine-tuning, reinforcement learning, and evaluation on single or multi-node GPU capacity. On the inference side, Modal offers OpenAI-compatible endpoints for open-weight models and lets teams deploy custom stacks and tune endpoints to match their traffic shape.

Underneath, Modal runs its own container runtime and image system designed for large images and fast GPU scheduling, along with a distributed filesystem for fast access to model weights and datasets. Capacity is drawn from a multi-cloud pool spanning many regions, with automatic routing to available hardware and continuous fleet health checks. Billing is usage-based, charged by the second while code runs, with granular cost controls. The company offers a free starting allowance and scalable paid usage, and markets to enterprises with SOC 2 Type II compliance and HIPAA readiness.

**Pricing & Plans:** Modal uses usage-based pricing billed by the second: a free monthly compute allowance gets you started, then you pay for the CPU, memory, and GPU resources your workloads consume. Enterprise plans and startup credits are available, and custom pricing can be discussed with sales.

- **Serverless Python functions:** Write plain Python, attach GPUs or containers, and deploy HTTPS endpoints that autoscale with traffic and scale to zero when idle.
- **Sandboxes for agents:** Launch isolated, secure environments for coding agents, RL rollouts, and untrusted code, with sub-second starts and support for over a million concurrent sandboxes.
- **Training and fine-tuning on demand:** Run fine-tunes, LoRA, full training, and reinforcement learning on elastic single or multi-node GPU capacity with no quota requests.
- **Model inference and endpoints:** Serve LLMs and image, video, or audio models through OpenAI-compatible endpoints, or bring your own inference stack and let Modal handle the infrastructure.
- **Fast storage and multi-cloud capacity:** A distributed filesystem loads large images and model weights at full bandwidth, while a pool spanning 20+ clouds routes workloads to the right hardware and region.

**Strengths:** Python-native developer experience with almost no infrastructure boilerplate; Scales from zero to thousands of GPUs with per-second, usage-based billing; Sandboxes are well suited to agentic and untrusted-code workloads; Multi-cloud capacity spans many regions with out-of-the-box observability and enterprise compliance

**Limitations:** Billed by real usage, so heavy GPU workloads can get expensive quickly without cost controls; Some advanced inference and enterprise features require working with the team rather than self-serve signup; The serverless model can feel less familiar to teams used to managing their own VMs or Kubernetes clusters

[Profile (Markdown)](https://openaitools.app/tool/modal-com.md)

## Union.ai

Union.ai grew out of the Flyte project, the open-source workflow engine used widely for data and ML pipelines, and it keeps that lineage in its design: you write ordinary Python tasks and task environments, and the runtime takes care of scheduling, caching, retries and typed data passing between steps. What Union adds on top is durability. If a run dies because a node disappears, a GPU is reclaimed, an API returns a 429 or an out-of-memory kill fires, the run is recovered and continues from the failed step rather than the beginning of the pipeline.

The current platform is organised around a handful of capabilities. The AI factory manages named, versioned artifacts so a checkpoint or dataset has a traceable producer and consumers, which matters for reproducibility. Production agents let teams keep the agent framework they already use, including OpenAI, Claude, PydanticAI and CrewAI, while making every turn of the loop durable, traced and sandboxed. The inference gateway puts external model APIs and self-hosted vLLM, SGLang or Ollama endpoints behind a single governed interface with virtual keys, budgets and guardrails. Around these sit scheduling primitives such as priority queues, concurrency limits, quotas and cluster selectors.

Deployment is deliberately bring-your-own-cloud. Union hosts the control plane, which stores references and metadata rather than payloads, while your data, models and compute stay inside your own perimeter, so your negotiated cloud rates and credits still apply. Union is available on AWS Marketplace and through self-service signup, with an optional managed-cluster service billed per cluster.

**Pricing & Plans:** Freemium-style entry with a free open-source Flyte option. The managed Team plan starts at a $950/month minimum, fully credited to usage, with the first month free and no card required at signup. Consumption is metered on actions, vCPU-hours, memory GB-hours and GPU-hours across published volume bands. Enterprise is custom-priced on an annual commit with volume discounts, and optional Union-managed clusters cost $500 per cluster per month, capped at $2,500.

- **Durable execution engine:** Tasks, traces and artifacts survive infrastructure failure. Runs fork, recover and replay from the last good step instead of starting over, with retries and caching handled by the runtime.
- **AI factory and artifact lineage:** Named, typed and versioned artifacts wire teams together, with lineage showing which run produced each version and which downstream tasks consume it.
- **Sovereign, bring-your-own-cloud deployment:** Run the control plane in Union's cloud while workloads execute on clusters in your AWS, GCP, Azure or neocloud account, under your own security perimeter.
- **Production agents and agent traceability:** Bring OpenAI, Claude, PydanticAI or CrewAI agents; each turn is traced and sandboxed in ephemeral containers, MCP servers and human approvals supported.
- **Inference gateway:** One gateway for hosted LLM providers and self-hosted vLLM, SGLang or Ollama endpoints, with virtual keys, budgets, guardrails and per-GPU observability.
- **Advanced scheduling and quotas:** Priority, concurrency, quotas and cluster selectors on queues, so backfills never steal capacity from production training or serving jobs.

**Strengths:** Durable execution means long training, inference and agent runs survive node loss, spot reclamation and API rate limits; Bring-your-own-cloud architecture keeps data, models and secrets inside your own security perimeter; Backed by the creators of Flyte, so the open-source engine and the managed platform evolve together; Transparent published rate card with marginal volume bands for actions, CPU, memory and GPU

**Limitations:** The Team plan carries a $950/month minimum that is only credited back as usage, so it is a poor fit for hobbyists or very small experiments; Because workloads run inside your own cloud, you still pay your cloud provider for compute on top of Union's metering; Setup expects a Kubernetes cluster and familiarity with Python task environments, which raises the bar for non-engineering users; Rate-card pricing across four meters (actions, vCPU, memory, GPU) can be hard to forecast without monitoring

[Profile (Markdown)](https://openaitools.app/tool/union-cloud.md)

## Frequently Asked Questions

### How do Modal and Union.ai compare in monthly traffic?

Modal has 1,196,021 monthly visits, while Union.ai has 17,787. Traffic estimates describe audience size, not product quality.

### How do their growth rates compare?

Modal has a month-over-month growth rate of +30.2%; Union.ai has -28.4%.

### How does pricing compare?

Modal: Freemium, Contact for Pricing. Modal uses usage-based pricing billed by the second: a free monthly compute allowance gets you started, then you pay for the CPU, memory, and GPU resources your workloads consume. Enterprise plans and startup credits are available, and custom pricing can be discussed with sales. Union.ai: Freemium, Contact for Pricing. Freemium-style entry with a free open-source Flyte option. The managed Team plan starts at a $950/month minimum, fully credited to usage, with the first month free and no card required at signup. Consumption is metered on actions, vCPU-hours, memory GB-hours and GPU-hours across published volume bands. Enterprise is custom-priced on an annual commit with volume discounts, and optional Union-managed clusters cost $500 per cluster per month, capped at $2,500.

## Alternatives

| # | Tool Name | Monthly Visits | MoM Growth Rate | Pricing Model | Summary | Profile (Markdown) |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | [fal.ai](https://openaitools.app/tool/fal-ai) | 3,093,684 | -3.7% | Paid, pay-as-you-go usage-based pricing | Extremely fast serverless execution optimized specifically for generative media models rather than general Python code. | [.md](https://openaitools.app/tool/fal-ai.md) |
| 2 | [RunPod](https://openaitools.app/tool/runpod) | 2,881,043 | +5.9% | Paid | The AI developer cloud for GPU pods, serverless inference and clustering | [.md](https://openaitools.app/tool/runpod.md) |
| 3 | [Together AI](https://openaitools.app/tool/together-ai) | 1,645,930 | +64.9% | Freemium, Paid | Together AI is the AI Native Cloud — a full-stack platform for running, fine-tuning and training open-source models. It spans serverless inference APIs, dedicated endpoints, GPU clusters, post-training and storage, all b | [.md](https://openaitools.app/tool/together-ai.md) |
| 4 | [Vast.ai](https://openaitools.app/tool/vast-ai) | 1,257,554 | +2.8% | Paid | Rent cloud GPUs by the second from a global marketplace | [.md](https://openaitools.app/tool/vast-ai.md) |
| 5 | [Nebius](https://openaitools.app/tool/nebius) | 1,145,711 | +10.7% | Paid, Contact for Pricing | An AI-native cloud built from silicon to API for training, tuning, and serving models | [.md](https://openaitools.app/tool/nebius.md) |
| 6 | [Replicate AI](https://openaitools.app/tool/replicate-ai) | 904,038 | -8.4% | Paid | Easier model packaging via Cog, but offers less arbitrary serverless Python container execution than Modal. | [.md](https://openaitools.app/tool/replicate-ai.md) |
| 7 | [DeepInfra](https://openaitools.app/tool/deep-infra) | 457,810 | -8.9% | Paid | Low-cost serverless inference APIs for 200+ open models | [.md](https://openaitools.app/tool/deep-infra.md) |
| 8 | [Lightning AI](https://openaitools.app/tool/lightning-ai) | 272,562 | -12.3% | Freemium, Paid, Contact for Pricing | The AI cloud built by the creators of PyTorch Lightning | [.md](https://openaitools.app/tool/lightning-ai.md) |
| 9 | [Novita AI](https://openaitools.app/tool/novita-ai) | 271,371 | -10.4% | Paid | Combines ready-to-use model APIs and serverless GPU jobs, with simpler API consumption than custom Modal apps. | [.md](https://openaitools.app/tool/novita-ai.md) |
| 10 | [FluidStack](https://openaitools.app/tool/fluidstack) | 154,620 | +7.3% | Paid, Contact for Pricing | Gigawatt-scale AI compute, built and operated end to end | [.md](https://openaitools.app/tool/fluidstack.md) |

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Source: https://openaitools.app/compare/modal-com-vs-union-cloud

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