Skip to content
← All framework rankings

FastAPI vs Flask

Security & risk comparison · Updated June 2026

How does FastAPI compare to Flask on security, AI-readiness, and total cost of ownership? We scored both across 7 dimensions using NVD/NIST CVE data, GitHub metrics, and our scan of 10M+ sites.

Key finding

FastAPI scores 82/100 overall versus Flask's 63/100. FastAPI has 8 total CVEs compared to Flask's 30, giving it a smaller vulnerability surface. (Source: WebPulse framework scoring, NVD/NIST, July 2026)

82
FastAPI
Modern · PYTHON
vs
63
Flask
Modern · PYTHON
Dimension-by-dimension breakdown
security FastAPI
90
75
FastAPI
Flask
performance Tie
65
65
FastAPI
Flask
ecosystem FastAPI
85
50
FastAPI
Flask
ai readiness FastAPI
95
70
FastAPI
Flask
developer experience FastAPI
88
70
FastAPI
Flask
market trajectory FastAPI
70
40
FastAPI
Flask
cost of ownership FastAPI
75
60
FastAPI
Flask
Security details
Metric FastAPI Flask
Total CVEs 8 30
Critical CVEs 0 3
Exploited (KEV) 0 0
CVEs last year 2 5
Avg CVSS 3.5 4.8
Security score 90/100 75/100
Recommended
FastAPI

FastAPI scores 83/100. Verdict: Recommended.

Acceptable
Flask

Flask scores 64/100. Verdict: Acceptable.

Quick facts
FastAPI
Category: Backend
Language: PYTHON
First release: 2018
Generation: Modern
Trend: Rising
Market share: 0.6%
Flask
Category: Backend
Language: PYTHON
First release: 2010
Generation: Modern
Trend: Stable
Market share: 0.5%
Related briefings
8 Frameworks Shipped Updates in One Week — Why It Matters
July 2, 2026
Release Velocity This Week: Vue, Angular, and FastAPI All Ship
June 26, 2026
The API-First Stack: FastAPI + Modern Frontend Is the New Greenfield Default
June 22, 2026
Netflix's Lemur Shows Why JWT Algorithm Pinning Is Non-Negotiable
June 26, 2026
More comparisons
FastAPI vs WordPress FastAPI vs Next.js FastAPI vs Drupal FastAPI vs React FastAPI vs Angular FastAPI vs Django FastAPI vs Laravel FastAPI vs Vue.js FastAPI vs Astro FastAPI vs Hugo FastAPI vs SvelteKit FastAPI vs Rails Flask vs WordPress Flask vs Next.js Flask vs Drupal Flask vs React Flask vs Angular Flask vs Django Flask vs Laravel Flask vs Vue.js Flask vs Astro Flask vs Hugo Flask vs SvelteKit Flask vs Rails

Data sourced from NVD/NIST CVE database, GitHub API, and WebPulse framework scanner. Scores calculated using a 7-dimension model covering security, performance, ecosystem health, AI-readiness, developer experience, market trajectory, and cost of ownership. Updated June 2026.