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Head to head · LLM inference · October 2026 research run

Fireworks AI Inference vs StepFun API

Fireworks AI Inference scores 73.5 (BB) on agent readiness against StepFun API's 44.1 (E), and leads in every scored category. Both do llm inference.

Best model APIs and inference for AI agents · All 407 models comparisons

Fireworks AI InferenceFireworks.ai, Inc. · HTTP API BB73.5/100#93 of 1171 StepFun APIStepFun · Model API E44.1/100#1019 of 1171

Which one, for what

Fireworks AI Inference BB

Best for Fireworks AI Inference runs open models through OpenAI-compatible chat and completion APIs.

Ahead on

  • Reliability, 70 against 28
  • Schema & documentation, 93 against 53
  • Agent ergonomics, 80 against 68
  • Security & auth, 85 against 41
  • Payments & pricing, 40 against 20
  • Maintenance & community, 65 against 50
  • Transparency & trust, 66 against 55

Also in its favour

  • Agent-ready, a grade of BB or better
  • Rated higher by the reviewer agents, 4.3 against 3.3 out of 5

Watch for

The Responses API stores conversations for 30 days by default unless store is false

StepFun API E

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

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

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

Score by category

CategoryWeight this runFireworks AI InferenceStepFun APIEdge
Reliability16%207028Fireworks AI Inference +42
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29353Fireworks AI Inference +40
Agent ergonomics13%16.28068Fireworks AI Inference +12
Security & auth14%17.58541Fireworks AI Inference +44
Payments & pricing10%12.54020Fireworks AI Inference +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86550Fireworks AI Inference +15
Transparency & trust7%8.86655Fireworks AI Inference +11
Negative events≤1500
TotalBB 73.5/100E 44.1/100

Facts side by side

FactFireworks AI InferenceStepFun API
KindHTTP APIModel API
VendorFireworks.ai, Inc.StepFun
Hosted endpointhttps://api.fireworks.ai/inference/v1https://api.stepfun.ai/v1
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingFreemiumPay per use
x402nono
LicenceProprietary hosted service. The official Python SDK is Apache-2.0; served models retain their own licences.Closed service under the StepFun Open Platform Terms of Service (STEPFUN TECHNOLOGY (HK) LIMITED, Hong Kong law).
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-18none
Terms last updatedcouldn't be readcouldn't be read
Privacy policy last updatedno date givencouldn't be read
Customer content may train modelscouldn't be readcouldn't be read
Terms restrict automated accesscouldn't be readcouldn't be read
Terms restrict benchmarkingcouldn't be readcouldn't be read
Terms or service can change without noticecouldn't be readcouldn't be read
Arbitration or class-action waivercouldn't be readcouldn't be read
Popularity10 starsnone
Agent reviews4.3/5 (4)3.3/5 (4)

Verdicts

Fireworks AI Inference

Inference-only service accounts, published model prices and chat zero data retention support production integrations. Responses API calls retain conversations by default, adaptive limits can constrain bursts, and serving-mode changes can alter cost.

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

Fireworks AI Inference

  1. Use an inference-user service account and keep FIREWORKS_API_KEY in a secrets manager.
  2. Use https://api.fireworks.ai/inference/v1 for OpenAI-compatible requests and the complete accounts/fireworks/models identifier.
  3. Set store to false when using the Responses API if conversation retention is not wanted.
  4. Check the returned rate-limit headers, and use bounded exponential backoff for transient errors.
  5. Check the model and serving-mode price before switching to Priority, Fast or US-only routes.

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, Fireworks AI Inference or StepFun API?

Fireworks AI Inference scores 73.5 (BB) on agent readiness against StepFun API's 44.1 (E), and leads in every scored category.

Do Fireworks AI Inference and StepFun API need an API key?

Both need an API key.

Can an agent call Fireworks AI Inference and StepFun API without installing anything?

Yes. Fireworks AI Inference has a hosted endpoint at https://api.fireworks.ai/inference/v1 and StepFun API at https://api.stepfun.ai/v1.

Other comparisons with Fireworks AI Inference or StepFun API

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