# Cloudflare Workers AI vs StepFun API

> Cloudflare Workers AI scores 68.3 (B) to StepFun's 44.4 (E) for llm inference. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-stepfun-api
- Markdown: https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-stepfun-api.md (~2,850 tokens)
- Slim: https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-stepfun-api.min.md (~780 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-stepfun-api.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-12

Cloudflare Workers AI scores 68.3 (B) on agent readiness against StepFun API's 44.4 (E), and leads in every scored category. Both do llm inference.

- Cloudflare Workers AI: grade B, 68.3/100, rank #226 of 965. Markdown https://www.anchorterminal.com/tools/cloudflare-workers-ai.md · JSON https://www.anchorterminal.com/api/v1/tools/cloudflare-workers-ai.json
- StepFun API: grade E, 44.4/100, rank #889 of 965. Markdown https://www.anchorterminal.com/tools/stepfun-api.md · JSON https://www.anchorterminal.com/api/v1/tools/stepfun-api.json
- Best model APIs and inference for AI agents: https://www.anchorterminal.com/best/inference/index.md
- All 153 models comparisons: https://www.anchorterminal.com/compare/inference/index.md

## Which one, for what

### Cloudflare Workers AI (B)

Good for: Agents that already run on Cloudflare Workers, or that want open-weight chat, embedding, reranking, speech and image models behind one token with a free daily allowance.

Ahead on:
- Reliability, 66 against 28
- Schema & documentation, 80 against 53
- Agent ergonomics, 75 against 68
- Security & auth, 77 against 41
- Payments & pricing, 52 against 20
- Maintenance & community, 72 against 50
- Transparency & trust, 76 against 58

Watch for: No SLA for Workers AI was found in the docs or the agreements read

### StepFun API (E)

Good for: Long-context agent and coding work over text, screenshots and video at a low per-token price, where a preview model is acceptable.

Also in its favour:
- No incidents deducted, where Cloudflare Workers AI loses 3 points for them

Watch for: Step 5 Preview is labelled a preview, and no release date or support commitment was found


## Score by category

| Category | Weight | Cloudflare Workers AI | StepFun API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 66 | 28 | Cloudflare Workers AI +38 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 80 | 53 | Cloudflare Workers AI +27 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 68 | Cloudflare Workers AI +7 |
| Security & auth | 14% (17.5 this run) | 77 | 41 | Cloudflare Workers AI +36 |
| Payments & pricing | 10% (12.5 this run) | 52 | 20 | Cloudflare Workers AI +32 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 72 | 50 | Cloudflare Workers AI +22 |
| Transparency & trust | 7% (8.8 this run) | 76 | 58 | Cloudflare Workers AI +18 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **68.3 · B** | **44.4 · E** | |

## Facts side by side

| Fact | Cloudflare Workers AI | StepFun API |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Cloudflare, Inc. | StepFun |
| Hosted endpoint | `https://api.cloudflare.com/client/v4/accounts/{account_id}/ai` | `https://api.stepfun.ai/v1` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Pay per use |
| x402 | payer tooling only | no |
| Licence | Proprietary service under Cloudflare's Self-Serve Subscription Agreement. Each hosted model carries its own open-weight licence, linked from its model page. The `cloudflare` SDKs are Apache-2.0, `workers-ai-provider` is MIT and the OpenAPI repository is BSD-3-Clause | Closed service under the StepFun Open Platform Terms of Service (STEPFUN TECHNOLOGY (HK) LIMITED, Hong Kong law). |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-01 | none |
| Terms last updated | 2025-09-12 |  |
| Privacy policy last updated | no date given |  |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | yes |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | yes |  |
| Arbitration or class-action waiver | yes |  |
| Popularity | 380k npm/wk | none |

## Verdicts

**Cloudflare Workers AI.** Per-model prices, rate limits and JSON Schemas are public, 10,000 neurons a day are free, and x402 payment is in beta on `/ai/run` for four models. No SLA was found, three models moved to paid-only access on 28 July 2026 with no notice, and several docs pages still use a model retired in May.

**StepFun API.** StepFun's API serves Step 5 Preview with a 1M-token context, video input, strict JSON Schema output and published per-token prices, documented in Markdown with an llms.txt. The model is a preview with no release date found, there's no free allowance or SLA, and the terms and privacy policy leave room to train on customer data.

## Before you call either

### Cloudflare Workers AI

1. Check the model page before calling. Seven models need Workers Paid or AI Gateway credits and return 403 with code 5035 on the Free plan
2. Read the internal code on a 429. 3036 means the day's 10,000 free neurons are spent until 00:00 UTC, 3040 means capacity, so retry later
3. Set `options.rejectIfBusy` to fail fast, or add `?queueRequest=true` for the batch route when the answer can wait
4. Send the same `x-session-affinity` value on every turn of a session to reach the prefix cache and the cached-input price
5. Keep paid frontier models under 20 requests a minute per model, or 50 with prepaid AI Gateway credits

### StepFun API

1. Set `max_tokens` yourself. It defaults to unlimited on Step 5 Preview, and reasoning tokens are billed as output
2. Use `response_format` with `type: json_schema` and `strict: true` when the shape matters. JSON Mode alone isn't schema-checked
3. Back off and retry on 429, 500, 503 and 504. The docs give no Retry-After header or backoff schedule
4. Expect HTTP 451 or `finish_reason: content_filter` when content fails StepFun's review, and don't retry the same input
5. Use api.stepfun.ai for the international platform. api.stepfun.com is the China platform with yuan pricing

## Questions

### Which is better for AI agents, Cloudflare Workers AI or StepFun API?

Cloudflare Workers AI scores 68.3 (B) on agent readiness against StepFun API's 44.4 (E), and leads in every scored category.

### Do Cloudflare Workers AI and StepFun API need an API key?

Both need an API key.

### Can an agent call Cloudflare Workers AI and StepFun API without installing anything?

Yes. Cloudflare Workers AI has a hosted endpoint at https://api.cloudflare.com/client/v4/accounts/{account_id}/ai and StepFun API at https://api.stepfun.ai/v1.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-stepfun-api.json, and with the fewest tokens: https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-stepfun-api.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "cloudflare-workers-ai", "b": "stepfun-api"}`. From a terminal: `anchor compare cloudflare-workers-ai stepfun-api`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/cloudflare-workers-ai.json and https://www.anchorterminal.com/api/v1/tools/stepfun-api.json

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