21st.dev vs BLACKBOX.AI
21st.dev vs BLACKBOX.AI, compared side by side on 19 data points: what each one does, how big it is, what it has raised, the tech running each site, and what users report. We score both out of 100 on traction, team and visibility: 21st.dev is on 46/100 and BLACKBOX.AI on 56/100.
Where each one leads
21st.dev
- agent readiness: 51/100 against 21/100
BLACKBOX.AI
- our overall score: 56/100 against 46/100
- domain rating: 81/100 against 67/100
- funding raised: $38.3M against $500K
At a glance
| Measure | 21st.dev | BLACKBOX.AI |
|---|---|---|
| What it is | AI-powered design tools and workflows. | BLACKBOX.AI is a coding LLM designed to transform software development by accelerating innovation and making engineers 10X faster in building and releasing products. |
| Category | AI, SaaS, Software Development, Frontend Development | AI, SaaS, Software Development, Agentic AI |
| Sells toBusiness model | B2B | B2B |
| Offering | Platform | Software |
| Founded | 2024 | 2020 |
| Headquarters | San Francisco, United States | San Francisco, United States |
| Status | Active | Active |
Size, funding and growth
| Measure | 21st.dev | BLACKBOX.AI |
|---|---|---|
| Employees | Not published | 176 |
| Total funding | $500K | $38.3M |
| Latest round | Seed | Pre-Seed |
| LinkedIn followers | Not published | 6,157 |
StartupHub scores
Our own 0-100 ratings. They measure company strength and site quality, not which product suits you.
| Measure | 21st.dev | BLACKBOX.AI |
|---|---|---|
| StartupHub scoreOur 0-100 rating | 46/100 | 56/100 |
| Traction | 28/100 | 58/100 |
| Team | 60/100 | 60/100 |
| Community | 15/100 | 8/100 |
| Search visibility | 9/100 | 67/100 |
| Quality | 48/100 | 58/100 |
| Agent readinessHow well an AI agent can read and act on the site | D (51/100) | F (21/100) |
| Domain ratingLink authority, 0-100 | 67/100 | 81/100 |
Technology
Detected on each public site, so it reflects the marketing stack as well as the product.
| Measure | 21st.dev | BLACKBOX.AI |
|---|---|---|
| Hosting | Vercel | Not detected |
| CDN | Vercel | Cloudflare |
| Frameworks | Next.js, Tailwind CSS | Not detected |
| Analytics | Google Analytics 4, Google Tag Manager, Facebook Pixel | Not detected |
| Open source | Yes | Yes |
Product and pricing
| Measure | 21st.dev | BLACKBOX.AI |
|---|---|---|
| Key features | Not published | Coding LLM, Autonomous AI Agents, BLACKBOX.AI Operator, LLM Integration & Access, Developer Copilot & Code Review |
21st.dev vs BLACKBOX.AI: common questions
Which is better, 21st.dev or BLACKBOX.AI?
On our 0-100 score BLACKBOX.AI rates higher (56/100 against 46/100). The score weights traction, team, visibility and profile completeness, so it reflects company strength rather than which product suits you. We compare the two on 19 data points above: read the rows that match what you are buying for.
How do 21st.dev and BLACKBOX.AI compare on the numbers?
21st.dev leads on agent readiness (51/100 against 21/100). BLACKBOX.AI leads on our overall score (56/100 against 46/100), domain rating (81/100 against 67/100), funding raised ($38.3M against $500K).
Read the full 21st.dev review and pricing or the BLACKBOX.AI review and pricing. You can also browse other 21st.dev alternatives we track.