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Comparison

Fidel vs Percy

Percy catches when your UI changes between builds. Fidel catches when your UI violates the Figma spec — the contract between design and engineering. Different problems, different baselines.

TL;DR

Percy is a visual regression tool. It takes screenshots of your UI and compares them against a previous baseline to catch unintended changes between builds. Fidel is a design validation tool. It compares your live page against the Figma spec — the contract that defines what correct looks like. Percy answers "did something change?" Fidel answers "does the implementation match the contract?"

At a Glance

Feature Comparison

Fidel Percy (BrowserStack)
Compares against Figma design spec (source of truth) Previous screenshot baseline
What it catches Design spec violations — spacing, color, typography drift from Figma Visual regressions — any pixel difference from the last approved build
Output Expected vs actual values per property (e.g., font-size: 16px vs 14px) Screenshot diff with highlighted pixel regions
Setup Two inputs — Figma URL + deploy URL SDK integration + test code + snapshot commands per page
CI integration GitHub Action — add to workflow YAML SDK (Cypress, Playwright, Storybook, etc.)
Review workflow Severity-ranked issues on the PR Visual review dashboard with approve/reject per snapshot
Test maintenance None — no selectors, no baseline management Baseline updates required when intentional changes ship
Scoring 0–100 match score per page No score — pass/fail per snapshot
Design file required Yes — Figma No
Cross-browser Chromium-based browsers 10+ browser/OS combinations
Pricing Free during beta (pricing TBD) From $399/month (5,000 screenshots)

What Percy does well

Percy has broad adoption for visual regression testing. If your team needs to catch unintended visual changes across 10+ browser/OS combinations, Percy is well-suited for that.

Its review dashboard lets teams approve or reject each screenshot, where reviewers maintain the baseline over time. For teams with complex component libraries in Storybook, Percy's integration is mature and well-documented.

Percy is the right choice if your primary concern is: "Did we accidentally change something that was already working?"

Percy — Visual Regression
Baseline Previous approved build
Detection Pixel difference
Question "Did something change?"
Cross-browser 10+ combos
Maintenance Baseline updates
Fidel — Design Validation
Baseline Figma design file
Detection Property-level diff
Question "Does this match the contract?"
Setup Zero config
Maintenance None

What Fidel does differently

Fidel doesn't compare your UI against a previous version of itself. It compares against the Figma spec — the contract between design and engineering that defines what correct looks like.

This means Fidel catches problems visual regression tools can't: a heading that was always the wrong font size, a button color that drifted gradually across several PRs — each change small enough to approve, but the cumulative effect violates the spec — or spacing that was never right in the first place. If the implementation deviates from the contract, everything downstream inherits that error.

Fidel reports expected vs actual values per CSS property — not just "something changed in this region." No test code required. Add it to your CI workflow with a Figma URL and deploy URL.

The gap visual regression can't fill

Visual regression tools have a fundamental blind spot: they inherit whatever was already wrong. If the initial implementation had a 2px spacing error, that error becomes the approved baseline. Every future build is compared against that wrong baseline, and the original contract violation is never caught.

This compounds silently. Each small deviation gets approved into the baseline because it "matches the last build." After months of development, the live site can look noticeably different from the Figma file, but Percy shows all green. The contract has been violated — but the regression tool never knew what the contract said.

Fidel closes this gap. It always compares against the Figma spec — the contract — regardless of what the previous build looked like. Contract violations are caught the moment they happen, not after they've been baked into the baseline.

Ready to try it? Sign up for the beta — two inputs, runs in CI in under 2 minutes.

Recommendation

Who should use what

Choose Fidel if you…

  • Need to validate that builds match the Figma design spec
  • Want severity-ranked issues with expected vs actual values on the PR
  • Don't want to write test code or maintain screenshot baselines
  • Ship fast with manual or AI-generated code and need automated design QA
  • Want a match score that tracks design accuracy over time

Choose Percy if you…

  • Need cross-browser visual regression testing (10+ browser/OS combos)
  • Want to catch any unintended visual change, even without a design file
  • Have a mature Storybook or component library setup
  • Need a visual review/approval workflow for a large team
  • Don't use Figma or don't have design specs to validate against

Use both? Percy and Fidel are complementary. Percy guards against regressions between builds. Fidel guards against drift from the design spec. Teams that care about both visual stability and design accuracy run both.

Questions

Frequently Asked

They solve different problems. Percy is a visual regression tool — it catches unintended changes from a previous baseline. Fidel is a design validation tool — it catches spec violations against the Figma file, which serves as the contract between design and engineering. Percy tells you what changed; Fidel tells you what's wrong. Many teams use both.
Yes. They solve different problems and are fully complementary. Percy catches when your UI changes unexpectedly between builds. Fidel catches when your UI doesn't match the Figma design. Teams that care about both visual stability and design accuracy use both.
No. Fidel requires zero test setup — just a Figma URL and a deploy URL. Percy requires SDK integration with your test framework (Cypress, Playwright, Storybook) and test code to capture screenshots at specific points. Fidel's GitHub Action runs in your CI workflow with no additional code.
Different approaches for different problems. Percy compares pixels — highly accurate for detecting any visual change, but pixel comparison can surface rendering-engine differences (e.g., sub-pixel font rendering across OS versions) that aren't meaningful to humans. Fidel uses heuristic matching to map Figma nodes to DOM elements, then compares 20+ CSS properties using perceptual color comparison (CIEDE2000). Each issue includes expected vs actual values and confidence scores.
Yes. Percy supports 10+ browser and OS combinations, which is valuable for catching rendering differences across Chrome, Firefox, Safari, Edge, and mobile browsers. Fidel currently validates against Chromium-based browsers. If cross-browser rendering consistency is your primary concern, Percy is the better tool for that.
Percy starts at $399/month for 5,000 screenshots, scaling up based on usage. Fidel is free during beta. Fidel doesn't use screenshot-based comparison, so there's no per-snapshot billing model.

Validate against the contract, not the last build

The Figma spec is the source of truth. Fidel enforces it on every PR. Free during beta — zero setup, runs in CI in under 2 minutes.

Sign Up for Beta