Bundle Size Comparison of Form Libraries

Choosing the right form library significantly impacts your application's performance, especially on mobile devices and slow networks. This comprehensive comparison analyzes bundle sizes of four popular form libraries: FormEngine Core, SurveyJS, react-jsonschema-form (RJSF), and Vueform, helping you make an informed decision based on actual shipping code rather than feature lists.

Why bundle size matters for form libraries

Modern web applications face strict performance budgets, particularly when serving users on mobile devices or in regions with limited network connectivity. Every kilobyte of JavaScript affects load times, user experience, and conversion rates.

The performance impact of bundle size

Additional JavaScript	Slow 3G Impact	4G Impact	User Experience Impact
+50 KB	~1.5–1.7 seconds	~0.15 seconds	Noticeable delay on mobile
+100 KB	~2.6–2.8 seconds	~0.30 seconds	Significant delay, possible abandonment
+300 KB	~7.0–7.5 seconds	~0.70 seconds	High abandonment rate
+500 KB	~11–12 seconds	~1.1 seconds	Critical performance issue

Form libraries, while essential for user interaction, can contribute substantially to your total JavaScript payload. Understanding how different libraries approach bundle size helps you choose one that aligns with your performance goals.

Testing methodology and fair comparison

info

All mentioned tools, testing data, and the complete test suite are available in our GitHub repository. The repository includes build configurations, test applications for each library, and scripts to reproduce these measurements. Feel free to explore the code, run your own tests, or contact us with questions.

To ensure accurate, comparable results, we implemented a standardized testing approach:

Test scenarios

• Login form: Simple form with email and password fields
• Booking form: Complex multi-step form with validation and conditional logic

Tooling assumptions

• Build tool: Vite (default production configuration)
• Optimizations: Minification + gzip enabled
• Tree-shaking: Enabled by default
• UI variations: Tested with default UI and Material UI (MUI) where applicable

Equalization approaches

1. Duplicate package removal: Eliminated version mismatches
2. UI kit equalization: Tested with and without Material UI
3. Tree-shaking evaluation: Measured effectiveness of dead code elimination

Bundle size results: gzipped comparison

The following tables present gzipped bundle sizes for each library across different scenarios. Gzipped size represents what actually travels over the network to users' browsers.

Simple login form results

Library	Default UI Size	With Material UI	Difference	Key Insight
Vueform	140.72 KB	141.09 KB	+0.37 KB	Minimal change, smallest baseline
RJSF	175.26 KB	231.62 KB	+56.36 KB	MUI adds significant overhead
FormEngine Core	244.19 KB	188.54 KB	-55.65 KB	Only library that reduces size with MUI
SurveyJS	421.67 KB	391.72 KB	-29.95 KB	Large baseline, modest reduction

Complex booking form results

Library	Default UI Size	With Material UI	Difference	Key Insight
Vueform	199.06 KB	199.23 KB	+0.17 KB	Stable size, integrated UI
RJSF	178.07 KB	234.50 KB	+56.43 KB	Predictable growth with MUI
FormEngine Core	316.69 KB	199.26 KB	-117.43 KB	Dramatic 37% reduction with MUI
SurveyJS	423.75 KB	455.73 KB	+31.98 KB	Inconsistent MUI impact

Architectural analysis: Why results vary

Different libraries adopt distinct architectural approaches that directly impact their bundle size characteristics.

FormEngine Core: The modular advantage

FormEngine's pluggable architecture enables complete UI replacement. When you switch from its default React Suite components to Material UI:

Important

FormEngine's modular design means you only pay for what you use. When integrated with Material UI, the default React Suite components are completely removed from your bundle, resulting in significant size reductions.

• Complete UI replacement: Default UI components are entirely removed
• Optimal tree-shaking: Unused code is effectively eliminated
• Zero UI overhead: No duplicate UI code shipped
• Best-in-class MUI integration: Actually reduces bundle size

This makes FormEngine Core particularly valuable for teams already using established UI libraries like Material UI.

Vueform: Integrated efficiency

Vueform delivers the smallest baseline through tight integration:

• Monolithic architecture: UI, validation, and rendering are coupled
• Stable size: Consistent across UI variations
• Suitable for: Standalone applications with strict size budgets

RJSF: Predictable performance

RJSF offers predictable bundle growth:

• Small core runtime: Lightweight foundation
• Linear scaling: Bundle size grows with feature usage
• MUI overhead: Adds 21-32% to bundle size

SurveyJS: Feature-rich foundation

SurveyJS prioritizes features over size:

• Large baseline: Substantial runtime even for simple forms
• Framework-agnostic: Flexibility comes at a size cost
• Inconsistent optimization: MUI impact varies by scenario
• Best for: Survey-focused applications needing extensive features

Key takeaways for library selection

When using Material UI or established UI libraries

Choose FormEngine Core for optimal size-to-capability ratio

FormEngine Core is the only library that reduces bundle size when integrating with Material UI, achieving 40-48% reduction compared to React Suite UI. This makes it ideal for teams leveraging existing UI infrastructure.

Benefits:

• Complete UI replacement eliminates default UI overhead
• Exceptional tree-shaking removes unused code
• Future-proof architecture adapts to any UI library
• Best performance for complex forms with MUI

When building from scratch with minimal dependencies

Choose Vueform for the smallest baseline

Vueform delivers the most compact bundles when no external UI library is required, making it suitable for standalone applications or strict performance budgets.

When needing predictable, controllable growth

Choose RJSF for linear scaling

RJSF offers predictable bundle sizes, though Material UI integration adds measurable overhead.

When survey-specific features are essential

Choose SurveyJS for specialized capabilities

SurveyJS provides extensive survey-focused features but carries a substantial size penalty that may not justify the cost for general form use cases.

Practical recommendations

For performance-critical applications

1. Audit your UI library usage: If already using Material UI, FormEngine Core provides the best efficiency
2. Consider network conditions: On Slow 3G networks, every 50KB adds ~1.5 seconds to load time
3. Test with your actual forms: Bundle size impact varies with form complexity
4. Monitor tree-shaking effectiveness: Use bundle analyzers to verify dead code elimination

Integration considerations

• FormEngine Core: Requires UI library selection but offers maximum flexibility
• Vueform: Works best with its integrated UI, limited external UI support
• RJSF: Good Material UI integration but adds overhead
• SurveyJS: Limited UI kit support, primarily uses custom rendering

Summary

FormEngine's architecture makes it the most efficient choice for teams already invested in UI library ecosystems, while Vueform offers the smallest footprint for new projects. The choice ultimately depends on your specific constraints around existing infrastructure, performance requirements, and feature needs.

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warning

Below is a detailed, in-depth library comparison with graphs. This may be of interest to those who plan to replicate these measurements and compare them with our results.

Detailed performance impact visualization

The chart below illustrates how bundle size affects load times across different network conditions:

Complete test data and methodology

Summary Matrix (Total Size)

Non-MUI (FormEngine Rsuite, RJSF, SurveyJS, VueForm)

App	login(raw/gzip)	booking(raw/gzip)
FormEngine Rsuite	1.04 MB / 245.07KB (+598.8 KB / +104.3 KB)	1.25 MB / 317.58KB (+673.1 KB / +139.1 KB)
RJSF	597.91 KB / 175.64KB (+132.3 KB / +34.9 KB)	607.27 KB / 178.48KB (0 KB / 0 KB)
SurveyJS	1.84 MB / 429.41KB (+1414.0 KB / +288.6 KB)	1.84 MB / 431.44KB (+1279.6 KB / +253.0 KB)
VueForm	465.56 KB / 140.78KB (0 KB / 0 KB)	716.41 KB / 198.99KB (+109.1 KB / +20.5 KB)

Legend: Bold values indicate the smallest value in each comparison. Smaller is better.

MUI (FormEngine MUI, RJSF, SurveyJS, VueForm)

App	login(raw/gzip)	booking(raw/gzip)
FormEngine MUI	622.40 KB / 189.44KB (+154.9 KB / +48.3 KB)	651.00 KB / 200.17KB (0 KB / +1.0 KB)
RJSF	725.37 KB / 232.64KB (+257.9 KB / +91.5 KB)	734.86 KB / 235.53KB (+83.9 KB / +36.4 KB)
SurveyJS	1.49 MB / 397.71KB (+1057.7 KB / +256.6 KB)	1.74 MB / 461.73KB (+1133.0 KB / +262.6 KB)
VueForm	467.50 KB / 141.16KB (0 KB / 0 KB)	716.06 KB / 199.16KB (+65.1 KB / 0 KB)

Legend: Bold values indicate the smallest value in each comparison. Smaller is better.

Comparison by App

FormEngine Core

Variant	Total Size(raw/gzip)	Chunks	Code(raw/gzip)	CSS(raw/gzip)
booking	1.25 MB / 317.58KB	2	842.18 KB / 265.16KB	438.18 KB / 52.42KB
booking-mui	651.00 KB / 200.17KB	2	650.82 KB / 200.00KB	186.00 B / 169.00B
login	1.04 MB / 245.07KB	2	626.23 KB / 192.65KB	438.18 KB / 52.42KB
login-mui	622.40 KB / 189.44KB	2	622.22 KB / 189.27KB	186.00 B / 169.00B

RJSF

Variant	Total Size(raw/gzip)	Chunks	Code(raw/gzip)	CSS(raw/gzip)
booking	607.27 KB / 178.48KB	2	489.77 KB / 159.11KB	117.50 KB / 19.38KB
booking-mui	734.86 KB / 235.53KB	2	734.35 KB / 235.24KB	518.00 B / 297.00B
login	597.91 KB / 175.64KB	2	480.72 KB / 156.37KB	117.18 KB / 19.27KB
login-mui	725.37 KB / 232.64KB	2	725.19 KB / 232.47KB	186.00 B / 169.00B

SurveyJS

Variant	Total Size(raw/gzip)	Chunks	Code(raw/gzip)	CSS(raw/gzip)
booking	1.84 MB / 431.44KB	2	1.54 MB / 396.10KB	305.64 KB / 35.34KB
booking-mui	1.74 MB / 461.73KB	2	1.74 MB / 460.94KB	2.22 KB / 808.00B
login	1.84 MB / 429.41KB	2	1.54 MB / 394.07KB	305.64 KB / 35.34KB
login-mui	1.49 MB / 397.71KB	2	1.49 MB / 397.55KB	186.00 B / 169.00B

VueForm

Variant	Total Size(raw/gzip)	Chunks	Code(raw/gzip)	CSS(raw/gzip)
booking	716.41 KB / 198.99KB	2	581.98 KB / 181.59KB	134.43 KB / 17.40KB
booking-mui	716.06 KB / 199.16KB	2	581.98 KB / 181.59KB	134.08 KB / 17.56KB
login	465.56 KB / 140.78KB	2	388.14 KB / 130.75KB	77.42 KB / 10.03KB
login-mui	467.50 KB / 141.16KB	2	389.68 KB / 130.92KB	77.82 KB / 10.23KB

Comparison by Variant

LOGIN

App	Total Size(raw/gzip)	Chunks	Code(raw/gzip)	CSS(raw/gzip)
SurveyJS	1.84 MB / 429.41KB (+1414.0 KB / +288.6 KB)	2	1.54 MB / 394.07KB	305.64 KB / 35.34KB
FormEngine Rsuite	1.04 MB / 245.07KB (+598.8 KB / +104.3 KB)	2	626.23 KB / 192.65KB	438.18 KB / 52.42KB
RJSF	597.91 KB / 175.64KB (+132.3 KB / +34.9 KB)	2	480.72 KB / 156.37KB	117.18 KB / 19.27KB
VueForm	465.56 KB / 140.78KB	2	388.14 KB / 130.75KB	77.42 KB / 10.03KB

Legend: Bold values indicate the smallest value in each comparison. Smaller is better.

Performance Comparison (using gzip sizes)

LOGIN-MUI

App	Total Size(raw/gzip)	Chunks	Code(raw/gzip)	CSS(raw/gzip)
SurveyJS	1.49 MB / 397.71KB (+1057.7 KB / +256.6 KB)	2	1.49 MB / 397.55KB	186.00 B / 169.00B
RJSF	725.37 KB / 232.64KB (+257.9 KB / +91.5 KB)	2	725.19 KB / 232.47KB	186.00 B / 169.00B
FormEngine MUI	622.40 KB / 189.44KB (+154.9 KB / +48.3 KB)	2	622.22 KB / 189.27KB	186.00 B / 169.00B
VueForm	467.50 KB / 141.16KB	2	389.68 KB / 130.92KB	77.82 KB / 10.23KB

Legend: Bold values indicate the smallest value in each comparison. Smaller is better.

Performance Comparison (using gzip sizes)

BOOKING

App	Total Size(raw/gzip)	Chunks	Code(raw/gzip)	CSS(raw/gzip)
SurveyJS	1.84 MB / 431.44KB (+1279.6 KB / +253.0 KB)	2	1.54 MB / 396.10KB	305.64 KB / 35.34KB
FormEngine Rsuite	1.25 MB / 317.58KB (+673.1 KB / +139.1 KB)	2	842.18 KB / 265.16KB	438.18 KB / 52.42KB
VueForm	716.41 KB / 198.99KB (+109.1 KB / +20.5 KB)	2	581.98 KB / 181.59KB	134.43 KB / 17.40KB
RJSF	607.27 KB / 178.48KB	2	489.77 KB / 159.11KB	117.50 KB / 19.38KB

Legend: Bold values indicate the smallest value in each comparison. Smaller is better.

Performance Comparison (using gzip sizes)

BOOKING-MUI

App	Total Size(raw/gzip)	Chunks	Code(raw/gzip)	CSS(raw/gzip)
SurveyJS	1.74 MB / 461.73KB (+1133.0 KB / +262.6 KB)	2	1.74 MB / 460.94KB	2.22 KB / 808.00B
RJSF	734.86 KB / 235.53KB (+83.9 KB / +36.4 KB)	2	734.35 KB / 235.24KB	518.00 B / 297.00B
VueForm	716.06 KB / 199.16KB (+65.1 KB / 0 KB)	2	581.98 KB / 181.59KB	134.08 KB / 17.56KB
FormEngine MUI	651.00 KB / 200.17KB (0 KB / +1.0 KB)	2	650.82 KB / 200.00KB	186.00 B / 169.00B

Legend: Bold values indicate the smallest value in each comparison. Smaller is better.

Performance Comparison (using gzip sizes)

Detailed Chunk Information

FormEngine Core

Variant: booking

Bundle Breakdown:

Category	Size	Percentage
Code	842.18 KB / 265.16KB	65.8%
CSS	438.18 KB / 52.42KB	34.2%

Chunks:

Chunk	Size
assets/booking-cLEyt4Rz.js	842.18 KB
assets/booking-BlfDlKZh.css	438.18 KB
Total	1.25 MB / 317.58KB

Variant: booking-mui

Bundle Breakdown:

Category	Size	Percentage
Code	650.82 KB / 200.00KB	100.0%
CSS	186.00 B / 169.00B	0.0%

Chunks:

Chunk	Size
assets/booking-mui-8oUcs06n.js	650.82 KB
assets/booking-mui-DRllDmdv.css	186.00 B
Total	651.00 KB / 200.17KB

Variant: login

Bundle Breakdown:

Category	Size	Percentage
Code	626.23 KB / 192.65KB	58.8%
CSS	438.18 KB / 52.42KB	41.2%

Chunks:

Chunk	Size
assets/login-CZHp6lqC.js	626.23 KB
assets/login-BlfDlKZh.css	438.18 KB
Total	1.04 MB / 245.07KB

Variant: login-mui

Bundle Breakdown:

Category	Size	Percentage
Code	622.22 KB / 189.27KB	100.0%
CSS	186.00 B / 169.00B	0.0%

Chunks:

Chunk	Size
assets/login-mui-Ck_0wiA4.js	622.22 KB
assets/login-mui-DRllDmdv.css	186.00 B
Total	622.40 KB / 189.44KB

RJSF

Variant: booking

Bundle Breakdown:

Category	Size	Percentage
Code	489.77 KB / 159.11KB	80.7%
CSS	117.50 KB / 19.38KB	19.3%

Chunks:

Chunk	Size
assets/booking-DJqT1Azw.js	489.77 KB
assets/booking-DmSkEnsk.css	117.50 KB
Total	607.27 KB / 178.48KB

Variant: booking-mui

Bundle Breakdown:

Category	Size	Percentage
Code	734.35 KB / 235.24KB	99.9%
CSS	518.00 B / 297.00B	0.1%

Chunks:

Chunk	Size
assets/booking-mui-COUHI9qn.js	734.35 KB
assets/booking-mui-Bomwm_CU.css	518.00 B
Total	734.86 KB / 235.53KB

Variant: login

Bundle Breakdown:

Category	Size	Percentage
Code	480.72 KB / 156.37KB	80.4%
CSS	117.18 KB / 19.27KB	19.6%

Chunks:

Chunk	Size
assets/login-V6rgUKiK.js	480.72 KB
assets/login-nEkMQGGj.css	117.18 KB
Total	597.91 KB / 175.64KB

Variant: login-mui

Bundle Breakdown:

Category	Size	Percentage
Code	725.19 KB / 232.47KB	100.0%
CSS	186.00 B / 169.00B	0.0%

Chunks:

Chunk	Size
assets/login-mui-ChXj5s7v.js	725.19 KB
assets/login-mui-DRllDmdv.css	186.00 B
Total	725.37 KB / 232.64KB

SurveyJS

Variant: booking

Bundle Breakdown:

Category	Size	Percentage
Code	1.54 MB / 396.10KB	83.8%
CSS	305.64 KB / 35.34KB	16.2%

Chunks:

Chunk	Size
assets/booking-BE-zW9Ik.js	1.54 MB
assets/booking-D3E-h4Sw.css	305.64 KB
Total	1.84 MB / 431.44KB

Variant: booking-mui

Bundle Breakdown:

Category	Size	Percentage
Code	1.74 MB / 460.94KB	99.9%
CSS	2.22 KB / 808.00B	0.1%

Chunks:

Chunk	Size
assets/booking-mui-tTf90JQr.js	1.74 MB
assets/booking-mui-DpJ2xjkN.css	2.22 KB
Total	1.74 MB / 461.73KB

Variant: login

Bundle Breakdown:

Category	Size	Percentage
Code	1.54 MB / 394.07KB	83.7%
CSS	305.64 KB / 35.34KB	16.3%

Chunks:

Chunk	Size
assets/login-qcT824kj.js	1.54 MB
assets/login-D3E-h4Sw.css	305.64 KB
Total	1.84 MB / 429.41KB

Variant: login-mui

Bundle Breakdown:

Category	Size	Percentage
Code	1.49 MB / 397.55KB	100.0%
CSS	186.00 B / 169.00B	0.0%

Chunks:

Chunk	Size
assets/login-mui-BtJbERC0.js	1.49 MB
assets/login-mui-DRllDmdv.css	186.00 B
Total	1.49 MB / 397.71KB

VueForm

Variant: booking

Bundle Breakdown:

Category	Size	Percentage
Code	581.98 KB / 181.59KB	81.2%
CSS	134.43 KB / 17.40KB	18.8%

Chunks:

Chunk	Size
assets/booking-FMlCJeul.js	581.98 KB
assets/booking-MdY-dgU2.css	134.43 KB
Total	716.41 KB / 198.99KB

Variant: booking-mui

Bundle Breakdown:

Category	Size	Percentage
Code	581.98 KB / 181.59KB	81.3%
CSS	134.08 KB / 17.56KB	18.7%

Chunks:

Chunk	Size
assets/booking-mui-CYQUKf4s.js	581.98 KB
assets/booking-mui-BnsU-ma9.css	134.08 KB
Total	716.06 KB / 199.16KB

Variant: login

Bundle Breakdown:

Category	Size	Percentage
Code	388.14 KB / 130.75KB	83.4%
CSS	77.42 KB / 10.03KB	16.6%

Chunks:

Chunk	Size
assets/login-DRWdQb0V.js	388.14 KB
assets/login-x6SVVLFq.css	77.42 KB
Total	465.56 KB / 140.78KB

Variant: login-mui

Bundle Breakdown:

Category	Size	Percentage
Code	389.68 KB / 130.92KB	83.4%
CSS	77.82 KB / 10.23KB	16.6%

Chunks:

Chunk	Size
assets/login-mui-DB0MzmEj.js	389.68 KB
assets/login-mui-CWmCCSP1.css	77.82 KB
Total	467.50 KB / 141.16KB