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Spar vs Mida

Mida runs the test. Spar decides which test runs.

Mida is a lightweight, developer-friendly test runner: a 15KB script that protects Core Web Vitals, a generous free tier, and MidaGX to build variants from a prompt or a drawing. It starts the moment you already know what to test. Spar is the autonomous CRO operator that answers what to test before the test exists, auditing the storefront, ranking every gap by revenue impact, and drafting the hypothesis and the variation code.

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Side by side

Spar vs Mida at a glance

Mida runs the test once you know what to test. Spar decides what to test, auditing the storefront and drafting the hypothesis and the variation code.

  • Workflow coverage
    Mida
    Audit
    Idea
    Test
    Measure
    Coverage: Audit not covered, Idea covered, Test covered, Measure covered
    Spar
    Audit
    Idea
    Test
    Measure
    Coverage: Audit covered, Idea covered, Test covered, Measure covered
  • Operating model
    MidaLightweight test runner with an AI variant builder. Starts at the question of what test you want to run.
    SparProductized growth team. Audits the storefront, ranks the bets, drafts the idea, ships the variation, declares the winner.
  • What the AI does
    MidaMidaGX generates variations from natural language prompts or screen drawings. MCP lets Claude, ChatGPT, and Cursor spawn tests. Scoped to ideation and variant creation.
    SparDiagnostic. Audits the storefront against an evidence library, ranks gaps by revenue impact, drafts the hypothesis, generates the variation code, declares the winner.
  • Where the test idea comes from
    MidaYour team. MidaGX suggests from prompts and a patterns library; the merchant decides which test to run.
    SparAn opinionated rule library scores every page type by evidence and revenue impact. Spar drafts the idea.
  • Evidence layer feeding test selection
    MidaPatterns page and CRO checklists. No citation-backed structured corpus.
    SparGA4 and Clarity fused with audit evidence. Every opportunity cites its on-page evidence.
  • Script weight and performance
    Mida15KB script. Protects Core Web Vitals and SEO.
    SparNative Shopify theme app extension. No flicker. Embed delivery for non-Shopify.
  • How winners get called
    MidaStats engine and reports. Your team reads and decides.
    SparSequential statistics declare the winner automatically. You can review the decision.
  • Pricing model
    MidaSandbox free (100k MTU, capped at 2 variants, tests, and goals). Growth $299/mo annual unlocks unlimited tests plus MAB and server-side. Enterprise custom.
    SparTransparent monthly tiers, published.
  • Storefront audit that finds UX gaps
  • Revenue-impact ranked opportunities
  • Citation-backed evidence library
  • AI-generated variation code from the audit
  • AI variant generation from prompts or drawings
  • MCP integration (Claude, ChatGPT, Cursor spawn tests)
  • On-page buyer journey analysis
  • Multiple design mockups
  • Ship-without-testing lane for obvious fixes
  • Auto-surfaced observations from GA4 and Clarity
  • 15KB script footprint
  • Generous free tier (100k MTU sandbox)
  • Multi-armed bandit
  • Server-side experimentation
  • Shareable stakeholder-ready CRO reports
  • Sequential statistical engine
The work between an idea and a shipped variation

Spar covers every stage.

Mida is a clean, light test runner with AI-assisted variants. The diagnostic stage is work the platform doesn't try to do.

  • 01Audit
    Find the highest-impact gaps on the storefront.
    Not in the boxNo automated audit. Patterns page and CRO checklists for self-serve.
    SparRule library scores every page type by evidence and revenue impact.
  • 02Ideation
    Turn the gap into a testable idea.
    Your team + MidaGXMidaGX suggests from prompts and patterns; your team decides which test to run.
    SparHypothesis drafted from the audit, evidence library, and VoC.
  • 03Variation code
    Build the variant that actually ships to traffic.
    Mida + your teamMidaGX generates variations from prompts or screen drawings; custom JS and CSS for bespoke.
    SparVariation code generated from the audit. You approve before live.
  • 04Ship & measure
    Roll out, gate by traffic, watch the result.
    Mida15KB script protects Core Web Vitals. Slack alerts. Separate app for replay and heatmaps.
    SparTheme app extension delivery. GA4 and Clarity wired in. No flicker.
  • 05Winning variation
    Decide what wins and what ships permanently.
    Your teamStats engine and reports. Your team reads and decides.
    SparSequential statistics declare the winner automatically. You review.

Illustrative. Spar's coverage reflects the product surface; Mida's owner labels reflect the typical setup the platform assumes.

Which one fits the team you have today

Pick Mida if

  • You already know what to test and just need a clean way to ship variants without hurting page speed.
  • Your priority is script weight, a free entry point, and developer-friendly tooling like MCP integration.
  • You want to spawn tests directly from Claude or Cursor as part of your dev workflow.
  • You're a solo operator or small Shopify merchant with a stocked test backlog.

Pick Spar if

  • Your backlog is "I think the PDP could be better" rather than a stocked test list.
  • You want an evidence-backed audit and a ranked opportunity list produced for you.
  • You want diagnostic AI that tells you what to fix and why, on top of variation-authoring AI.
  • You want the hypothesis, the mockup, and the variation code generated from one audit pass.
FAQ

Questions buyers ask

Run the test, or run the program

See the example site live, or start the 14-day free trial and let Spar audit your own store: ranked opportunities, evidence, and the first variation ready to test.

See an example site