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Comparison · 2 models · Updated Oct 4, 2026

Step 3.5 Flash 2603 vs Mercury Edit 2

Step 3.5 Flash 2603 comes out ahead, 62 to 35 on our weighted score, and it is the cheaper option too.

  1. Our pick

    StepFun

    Step 3.5 Flash 2603

    Released Apr 2, 2026

    62/100
    • ECI—
    • Price$0.10 / $0.30
    • Context256K
    Full specs Remove Step 3.5 Flash 2603

  2. Inception

    Mercury Edit 2

    Released Mar 30, 2026

    35/100
    • ECI—
    • Price$0.25 / $0.75
    • Context32K
    Full specs Remove Mercury Edit 2

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Step 3.5 Flash 2603 is our pick

Step 3.5 Flash 2603 is the better all-round choice, scoring 62/100 against Mercury Edit 2 (35). It leads on price, inputs & features and context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

  • CapabilityNot enough dataNo independent benchmark covers every model here yet
  • Lowest priceStep 3.5 Flash 2603Step 3.5 Flash 2603 $0.15 · Mercury Edit 2 $0.375 per 1M tokens (3:1 blend)
  • Longest contextStep 3.5 Flash 2603Step 3.5 Flash 2603 256,000 · Mercury Edit 2 32,000 tokens
  • Widest inputsSame inputsStep 3.5 Flash 2603: Text · Mercury Edit 2: Text
  • Self-hostingStep 3.5 Flash 2603Publishes downloadable weights
How the score is built
MeasureWeightStep 3.5 Flash 2603Mercury Edit 2
Price50%8970
Inputs & features30%350
Context window20%360
Overall100%62/10035/100

Left out because at least one model lacks the data: capability. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Step 3.5 Flash 2603 vs Mercury Edit 2 specifications side by side
SpecificationStep 3.5 Flash 2603StepFunMercury Edit 2Inception
Capability
Capabilities Index (ECI)——
ECI rank——
Price per million tokens
Input$0.10 (best)$0.25
Output$0.30 (best)$0.75
Cached input$0.02 (best)$0.025
Blended (3:1)$0.15 (best)$0.375
Long-context rateSame rateSame rate
Price sourceOfficial StepFun (Global) APIOfficial Inception API
Limits
Context window256,000 tokens (best)32,000 tokens
Max output256,000 tokens (best)8,192 tokens
Inputs and features
TextYesYes
ImagesNoNo
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYeslow · highNo
Tool callingYesNo
Structured outputNoNo
Availability
WeightsOpenProprietary
API model IDstep-3.5-flash-2603mercury-edit-2
API providers3 (best)1
ReleasedApr 2, 2026Mar 30, 2026
Knowledge cutoffJan 2025—
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • Step 3.5 Flash 2603$1.60
  • Mercury Edit 2$4.00
04 — Questions

Which should you choose?

Which is better: Step 3.5 Flash 2603 or Mercury Edit 2?

Step 3.5 Flash 2603 is the better all-round choice, scoring 62/100 against Mercury Edit 2 (35). It leads on price, inputs & features and context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

Which is cheaper, Step 3.5 Flash 2603 or Mercury Edit 2?

Step 3.5 Flash 2603 is cheaper at $0.10 input / $0.30 output per million tokens (official StepFun (Global) API price). Mercury Edit 2 costs $0.25 input / $0.75 output per million tokens (official Inception API price). At a typical mix of three input tokens to one output token, that is $0.15 per million tokens for Step 3.5 Flash 2603 versus $0.375 for Mercury Edit 2 (2.5× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. Step 3.5 Flash 2603 has not been scored yet and Mercury Edit 2 has not been scored yet.

Which is better for coding?

There are no published SWE-bench Verified results for Step 3.5 Flash 2603 and Mercury Edit 2 yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Note that Mercury Edit 2 does not support tool calling, which most coding agents need.

Which has the bigger context window?

Step 3.5 Flash 2603 has the largest context window at 256,000 tokens, against 32,000 for Mercury Edit 2. Maximum output per response: Step 3.5 Flash 2603 up to 256,000, Mercury Edit 2 up to 8,192 tokens.

Which can read images, PDFs, audio or video?

Step 3.5 Flash 2603 accepts text; Mercury Edit 2 accepts text. They handle the same number of input types.

Are any of these open source?

Step 3.5 Flash 2603 publishes its weights and can be self-hosted; Mercury Edit 2 is proprietary.

Which is newer?

Step 3.5 Flash 2603 is the newest, released Apr 2, 2026. Mercury Edit 2 came out Mar 30, 2026. Knowledge cutoff: Step 3.5 Flash 2603 Jan 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.

05 — Keep comparing

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