Serverless v Praxi: AWS Lambda vs Vercel Functions vs Cloudflare Workers

spinny:~/writing $ vim serverless-aws-lambda-vercel-cloudflare.md

1~
2Serverless computing vam umoznuje spoustet kod bez spravy serveru. Napisete funkce, nasadite je a platforma se postara o skalovani, dostupnost a infrastrukturu. V roce 2026 dominuji serverless krajine tri platformy: **AWS Lambda**, **Vercel Serverless Functions** a **Cloudflare Workers**. Kazda ma jine silne stranky a kompromisy.
3~
4V tomto clanku je porovnavame s realnymi priklady, uvahy o vykonu a analyzou cen.
5~
6## Jak Serverless funguje
7~
8```mermaid
9graph LR
10    User -- "HTTP Request" --> Gateway[API Gateway / Edge]
11    Gateway -- "Invoke" --> Function[Serverless Function]
12    Function -- "Response" --> User
13    Function -- "Read/Write" --> DB[(Database)]
14```
15~
16Nasadite funkci. Kdyz prijde pozadavek, platforma:
171. Spusti prostredi pro vykonavani (nebo znovu pouzije jiz zahrate)
182. Spusti vasi funkci
193. Vrati odpoved
204. Skaluje na nulu pri necinnosti (neplatite za cas necinnosti)
21~
22## Prehled platforem
23~
24### AWS Lambda
25~
26Originalni serverless platforma (spustena v roce 2014). Nejzralejsi a nejbohatsi na funkce, s hlubokou integraci do ekosystemu AWS.
27~
28```javascript
29// AWS Lambda handler
30export const handler = async (event) => {
31  const body = JSON.parse(event.body);
32~
33  const result = await processData(body);
34~
35  return {
36    statusCode: 200,
37    headers: { 'Content-Type': 'application/json' },
38    body: JSON.stringify(result),
39  };
40};
41```
42~
43### Vercel Serverless Functions
44~
45Tesne integrovano s Next.js a workflow nasazovani frontendu. Funkce se nasazuji spolecne s vasim frontendem bez jakekoli konfigurace.
46~
47```typescript
48// app/api/hello/route.ts (Next.js App Router)
49import { NextResponse } from 'next/server';
50~
51export async function GET(request: Request) {
52  const { searchParams } = new URL(request.url);
53  const name = searchParams.get('name') || 'World';
54~
55  return NextResponse.json({ message: `Hello, ${name}!` });
56}
57```
58~
59### Cloudflare Workers
60~
61Bezi na edge siti Cloudflare ve vice nez 300 mestech po celem svete. Pouziva V8 engine (stejny jako Chrome) misto Node.js, coz znamena extremne rychle cold starty.
62~
63```javascript
64// Cloudflare Worker
65export default {
66  async fetch(request, env) {
67    const url = new URL(request.url);
68    const name = url.searchParams.get('name') || 'World';
69~
70    return new Response(
71      JSON.stringify({ message: `Hello, ${name}!` }),
72      { headers: { 'Content-Type': 'application/json' } }
73    );
74  },
75};
76```
77~
78## Srovnani funkci
79~
80| Funkce | AWS Lambda | Vercel Functions | Cloudflare Workers |
81|---------|-----------|-----------------|-------------------|
82| **Runtime** | Node.js, Python, Go, Rust, Java, .NET | Node.js, Python, Go, Ruby | V8 Isolates (JS/TS, Rust via WASM) |
83| **Max. doba vykonavani** | 15 minut | 60s (Hobby), 300s (Pro) | 30s (zdarma), 15min (placeno) |
84| **Pamet** | 128MB - 10GB | 1024MB - 3008MB | 128MB |
85| **Cold start** | 100-500ms | 100-300ms | < 5ms |
86| **Misto nasazeni** | Jeden region (nebo multi s usilim) | Vice regionu | 300+ edge lokaci |
87| **Max. payload** | 6MB (synchronni), 256KB (asynchronni) | 4.5MB | 100MB |
88| **Vestavene uloziste** | Ne (pouzijte DynamoDB, S3) | Ne (pouzijte externi DB) | KV, D1 (SQLite), R2 (S3 kompatibilni) |
89| **Cenovy model** | Za pozadavek + doba trvani | Zahrnuto v planu | Za pozadavek + doba trvani |
90| **Bezplatna uroven** | 1M pozadavku/mesic | 100K/mesic (Hobby) | 100K pozadavku/den |
91~
92## Cold Starts
93~
94Cold start je cas potrebny k inicializaci nove instance funkce. Toto je nejvetsi vykonnostni problem u serverless.
95~
96```mermaid
97graph LR
98    subgraph "Cold Start"
99        A[Request] --> B[Provision Environment]
100        B --> C[Load Code]
101        C --> D[Initialize Runtime]
102        D --> E[Execute Function]
103    end
104~
105    subgraph "Warm Invocation"
106        F[Request] --> G[Execute Function]
107    end
108```
109~
110| Platforma | Typicky Cold Start | Proc |
111|----------|-------------------|-----|
112| **Cloudflare Workers** | < 5ms | V8 izolace, neni potreba plneho runtime |
113| **Vercel Functions** | 100-300ms | Node.js runtime na edge nebo regionalne |
114| **AWS Lambda** | 100-500ms | Uplna inicializace kontejneru |
115| **AWS Lambda (Java)** | 1-5 sekund | Rezijni naklady startu JVM |
116~
117Cloudflare Workers vyhravaiji cold starty s obrovskym naskokem, protoze pouzivaji V8 izolace misto kontejneru.
118~
119## Srovnani cen
120~
121### Bezplatna uroven
122~
123| Platforma | Bezplatne pozadavky | Bezplatny vypocet |
124|----------|--------------|--------------|
125| **AWS Lambda** | 1M/mesic | 400 000 GB-sekund |
126| **Vercel** | 100K/mesic | Zahrnuto v planu Hobby |
127| **Cloudflare Workers** | 100K/den (~3M/mesic) | 10ms CPU na vyvolani |
128~
129### Ve velkém (10M pozadavku/mesic, prumerna doba 50ms)
130~
131| Platforma | Odhadovane mesicni naklady |
132|----------|----------------------|
133| **AWS Lambda** | ~$2,50 (pozadavky) + ~$4,15 (vypocet) = **~$6,65** |
134| **Vercel** | **$20/mesic** (plan Pro, zahrnuje funkce) |
135| **Cloudflare Workers** | **$5/mesic** (placeny plan, zahrnuje 10M pozadavku) |
136~
137Pro vetsinu pripadu pouziti je Cloudflare Workers nejlevnejsi. Cenik Vercel je jednoduchy, ale zahrnuje celou platformu (hosting, CDN, analytika). AWS Lambda ma nejpodrobnejsi cenik.
138~
139## Realne pripady pouziti
140~
141### AWS Lambda: Nejlepsi pro
142~
143- **Slozite backendove procesy** - step functions, architektury rizene udalostmi
144- **Integraci se sluzbami AWS** - S3 triggery, DynamoDB streamy, SQS fronty
145- **Dlouho bezici ulohy** - az 15 minut doby vykonavani
146- **Vicejazycne tymy** - podporuje nejsirsi skalu runtime
147~
148```mermaid
149graph TD
150    S3[S3 Upload] --> Lambda1[Process Image]
151    Lambda1 --> SQS[SQS Queue]
152    SQS --> Lambda2[Generate Thumbnails]
153    Lambda2 --> DDB[DynamoDB]
154    DDB --> Lambda3[Send Notification]
155    Lambda3 --> SNS[SNS / Email]
156```
157~
158### Vercel Functions: Nejlepsi pro
159~
160- **Aplikace Next.js** - API routy bez konfigurace
161- **Tymy zamerene na frontend** - nasazeni frontendu a backendu spolecne
162- **Rychle prototypovani** - git push pro nasazeni
163- **Architektury Jamstack** - staticky frontend + serverless API
164~
165```typescript
166// app/api/subscribe/route.ts
167import { NextResponse } from 'next/server';
168~
169export async function POST(request: Request) {
170  const { email } = await request.json();
171~
172  // Validate
173  if (!email || !email.includes('@')) {
174    return NextResponse.json(
175      { error: 'Invalid email' },
176      { status: 400 }
177    );
178  }
179~
180  // Save to database
181  await db.subscribers.create({ email });
182~
183  return NextResponse.json({ success: true });
184}
185```
186~
187### Cloudflare Workers: Nejlepsi pro
188~
189- **API s nizkou latenci** - kod bezi na 300+ lokacich po celem svete
190- **Edge computing** - transformace odpovedi, A/B testovani, personalizace
191- **API s vysokym objemem** - nejlevnejsi ve velkém se stedy bezplatnou urovni
192- **Globalni aplikace** - data blizko uzivatelu s KV a D1
193~
194```javascript
195// Edge-side A/B test
196export default {
197  async fetch(request, env) {
198    const url = new URL(request.url);
199~
200    // Assign user to variant
201    const cookie = request.headers.get('Cookie') || '';
202    let variant = cookie.includes('ab=b') ? 'b' : 'a';
203~
204    if (!cookie.includes('ab=')) {
205      variant = Math.random() < 0.5 ? 'a' : 'b';
206    }
207~
208    // Fetch the appropriate version
209    const response = await fetch(`${url.origin}/variants/${variant}`);
210    const newResponse = new Response(response.body, response);
211~
212    // Set cookie for consistent experience
213    newResponse.headers.set('Set-Cookie', `ab=${variant}; Path=/; Max-Age=86400`);
214~
215    return newResponse;
216  },
217};
218```
219~
220## Kdy zvolit kterou
221~
222### Zvolte AWS Lambda pokud:
223- Jste jiz investovali do ekosystemu AWS
224- Potrebujete dlouho bezici funkce (az 15 minut)
225- Potrebujete slozite architektury rizene udalostmi
226- Potrebujete runtime krome JavaScriptu (Python, Go, Rust, Java)
227~
228### Zvolte Vercel Functions pokud:
229- Stavite s Next.js nebo frontendovym frameworkem
230- Chcete nejjednodussi zkusenost s nasazenim (git push)
231- Vas tym je zamereny na frontend
232- Chcete hosting + funkce + CDN na jedne platforme
233~
234### Zvolte Cloudflare Workers pokud:
235- Potrebujete co nejnizsi latenci globalne
236- Chcete nejlevnejsi moznost ve velkém
237- Potrebujete schopnosti edge computingu
238- Cas cold startu je kriticky pro vas pripad pouziti
239~
240## Lze je kombinovat?
241~
242Rozhodne. Bezna architektura:
243~
244```mermaid
245graph TD
246    User --> CF[Cloudflare Workers\nEdge caching, routing, A/B tests]
247    CF --> Vercel[Vercel\nNext.js frontend + API routes]
248    Vercel --> Lambda[AWS Lambda\nHeavy processing, background jobs]
249    Lambda --> S3[S3 Storage]
250    Lambda --> DB[(Database)]
251```
252~
253- **Cloudflare Workers**: edge smerovani, cachovani, bezpecnost
254- **Vercel Functions**: frontendove API routy, SSR
255- **AWS Lambda**: tezke backendove zpracovani, planovane ulohy, pipeline udalosti
256~
257## Zaver
258~
259Serverless vyrazne dozral. V roce 2026 zavisi volba mezi AWS Lambda, Vercel Functions a Cloudflare Workers na vasem stacku a prioritach:
260~
261- **Nejjednodussi zkusenost vyvojare**: Vercel
262- **Nejvykonnejsi a nejflexibilnejsi**: AWS Lambda
263- **Nejlepsi vykon a ceny**: Cloudflare Workers
264~
265Vsechny tri jsou pripraveny na produkci a overeny v boji. Zacnete s tou, ktera odpovida vasemu soucasnemu stacku, a rozsirojte se podle rustu vasich potreb.
266~

NORMAL · serverless-aws-lambda-vercel-cloudflare.md [readonly]266 lines · :q to close

2Serverless computing vam umoznuje spoustet kod bez spravy serveru. Napisete funkce, nasadite je a platforma se postara o skalovani, dostupnost a infrastrukturu. V roce 2026 dominuji serverless krajine tri platformy: **AWS Lambda**, **Vercel Serverless Functions** a **Cloudflare Workers**. Kazda ma jine silne stranky a kompromisy.

4V tomto clanku je porovnavame s realnymi priklady, uvahy o vykonu a analyzou cen.

6## Jak Serverless funguje

8```mermaid

9graph LR

10 User -- "HTTP Request" --> Gateway[API Gateway / Edge]

11 Gateway -- "Invoke" --> Function[Serverless Function]

12 Function -- "Response" --> User

13 Function -- "Read/Write" --> DB[(Database)]

14```

15~

16Nasadite funkci. Kdyz prijde pozadavek, platforma:

171. Spusti prostredi pro vykonavani (nebo znovu pouzije jiz zahrate)

182. Spusti vasi funkci

193. Vrati odpoved

204. Skaluje na nulu pri necinnosti (neplatite za cas necinnosti)

21~

22## Prehled platforem

23~

24### AWS Lambda

25~

26Originalni serverless platforma (spustena v roce 2014). Nejzralejsi a nejbohatsi na funkce, s hlubokou integraci do ekosystemu AWS.

27~

28```javascript

29// AWS Lambda handler

30export const handler = async (event) => {

31 const body = JSON.parse(event.body);

32~

33 const result = await processData(body);

34~

35 return {

36 statusCode: 200,

37 headers: { 'Content-Type': 'application/json' },

38 body: JSON.stringify(result),

39 };

40};

41```

42~

43### Vercel Serverless Functions

44~

45Tesne integrovano s Next.js a workflow nasazovani frontendu. Funkce se nasazuji spolecne s vasim frontendem bez jakekoli konfigurace.

46~

47```typescript

48// app/api/hello/route.ts (Next.js App Router)

49import { NextResponse } from 'next/server';

50~

51export async function GET(request: Request) {

52 const { searchParams } = new URL(request.url);

53 const name = searchParams.get('name') || 'World';

54~

55 return NextResponse.json({ message: `Hello, ${name}!` });

56}

57```

58~

59### Cloudflare Workers

60~

61Bezi na edge siti Cloudflare ve vice nez 300 mestech po celem svete. Pouziva V8 engine (stejny jako Chrome) misto Node.js, coz znamena extremne rychle cold starty.

62~

63```javascript

64// Cloudflare Worker

65export default {

66 async fetch(request, env) {

67 const url = new URL(request.url);

68 const name = url.searchParams.get('name') || 'World';

69~

70 return new Response(

71 JSON.stringify({ message: `Hello, ${name}!` }),

72 { headers: { 'Content-Type': 'application/json' } }

73 );

74 },

75};

76```

77~

78## Srovnani funkci

79~

81|---------|-----------|-----------------|-------------------|

85| **Cold start** | 100-500ms | 100-300ms | < 5ms |

87| **Max. payload** | 6MB (synchronni), 256KB (asynchronni) | 4.5MB | 100MB |

91~

92## Cold Starts

93~

94Cold start je cas potrebny k inicializaci nove instance funkce. Toto je nejvetsi vykonnostni problem u serverless.

95~

96```mermaid

97graph LR

98 subgraph "Cold Start"

99 A[Request] --> B[Provision Environment]

100 B --> C[Load Code]

101 C --> D[Initialize Runtime]

102 D --> E[Execute Function]

103 end

104~

105 subgraph "Warm Invocation"

106 F[Request] --> G[Execute Function]

107 end

108```

109~

110| Platforma | Typicky Cold Start | Proc |

111|----------|-------------------|-----|

112| **Cloudflare Workers** | < 5ms | V8 izolace, neni potreba plneho runtime |

113| **Vercel Functions** | 100-300ms | Node.js runtime na edge nebo regionalne |

114| **AWS Lambda** | 100-500ms | Uplna inicializace kontejneru |

115| **AWS Lambda (Java)** | 1-5 sekund | Rezijni naklady startu JVM |

116~

117Cloudflare Workers vyhravaiji cold starty s obrovskym naskokem, protoze pouzivaji V8 izolace misto kontejneru.

118~

119## Srovnani cen

120~

121### Bezplatna uroven

122~

123| Platforma | Bezplatne pozadavky | Bezplatny vypocet |

124|----------|--------------|--------------|

125| **AWS Lambda** | 1M/mesic | 400 000 GB-sekund |

126| **Vercel** | 100K/mesic | Zahrnuto v planu Hobby |

127| **Cloudflare Workers** | 100K/den (~3M/mesic) | 10ms CPU na vyvolani |

128~

129### Ve velkém (10M pozadavku/mesic, prumerna doba 50ms)

130~

131| Platforma | Odhadovane mesicni naklady |

132|----------|----------------------|

133| **AWS Lambda** | ~$2,50 (pozadavky) + ~$4,15 (vypocet) = **~$6,65** |

134| **Vercel** | **$20/mesic** (plan Pro, zahrnuje funkce) |

135| **Cloudflare Workers** | **$5/mesic** (placeny plan, zahrnuje 10M pozadavku) |

136~

137Pro vetsinu pripadu pouziti je Cloudflare Workers nejlevnejsi. Cenik Vercel je jednoduchy, ale zahrnuje celou platformu (hosting, CDN, analytika). AWS Lambda ma nejpodrobnejsi cenik.

138~

139## Realne pripady pouziti

140~

141### AWS Lambda: Nejlepsi pro

142~

143- **Slozite backendove procesy** - step functions, architektury rizene udalostmi

144- **Integraci se sluzbami AWS** - S3 triggery, DynamoDB streamy, SQS fronty

145- **Dlouho bezici ulohy** - az 15 minut doby vykonavani

146- **Vicejazycne tymy** - podporuje nejsirsi skalu runtime

147~

148```mermaid

149graph TD

150 S3[S3 Upload] --> Lambda1[Process Image]

151 Lambda1 --> SQS[SQS Queue]

152 SQS --> Lambda2[Generate Thumbnails]

153 Lambda2 --> DDB[DynamoDB]

154 DDB --> Lambda3[Send Notification]

155 Lambda3 --> SNS[SNS / Email]

156```

157~

158### Vercel Functions: Nejlepsi pro

159~

160- **Aplikace Next.js** - API routy bez konfigurace

161- **Tymy zamerene na frontend** - nasazeni frontendu a backendu spolecne

162- **Rychle prototypovani** - git push pro nasazeni

163- **Architektury Jamstack** - staticky frontend + serverless API

164~

165```typescript

166// app/api/subscribe/route.ts

167import { NextResponse } from 'next/server';

168~

169export async function POST(request: Request) {

170 const { email } = await request.json();

171~

172 // Validate

173 if (!email || !email.includes('@')) {

174 return NextResponse.json(

175 { error: 'Invalid email' },

176 { status: 400 }

177 );

178 }

179~

180 // Save to database

181 await db.subscribers.create({ email });

182~

183 return NextResponse.json({ success: true });

184}

185```

186~

187### Cloudflare Workers: Nejlepsi pro

188~

189- **API s nizkou latenci** - kod bezi na 300+ lokacich po celem svete

190- **Edge computing** - transformace odpovedi, A/B testovani, personalizace

191- **API s vysokym objemem** - nejlevnejsi ve velkém se stedy bezplatnou urovni

192- **Globalni aplikace** - data blizko uzivatelu s KV a D1

193~

194```javascript

195// Edge-side A/B test

196export default {

197 async fetch(request, env) {

198 const url = new URL(request.url);

199~

200 // Assign user to variant

201 const cookie = request.headers.get('Cookie') || '';

202 let variant = cookie.includes('ab=b') ? 'b' : 'a';

203~

204 if (!cookie.includes('ab=')) {

205 variant = Math.random() < 0.5 ? 'a' : 'b';

206 }

207~

208 // Fetch the appropriate version

209 const response = await fetch(`${url.origin}/variants/${variant}`);

210 const newResponse = new Response(response.body, response);

211~

212 // Set cookie for consistent experience

213 newResponse.headers.set('Set-Cookie', `ab=${variant}; Path=/; Max-Age=86400`);

214~

215 return newResponse;

216 },

217};

218```

219~

220## Kdy zvolit kterou

221~

222### Zvolte AWS Lambda pokud:

223- Jste jiz investovali do ekosystemu AWS

224- Potrebujete dlouho bezici funkce (az 15 minut)

225- Potrebujete slozite architektury rizene udalostmi

226- Potrebujete runtime krome JavaScriptu (Python, Go, Rust, Java)

227~

228### Zvolte Vercel Functions pokud:

229- Stavite s Next.js nebo frontendovym frameworkem

230- Chcete nejjednodussi zkusenost s nasazenim (git push)

231- Vas tym je zamereny na frontend

232- Chcete hosting + funkce + CDN na jedne platforme

233~

234### Zvolte Cloudflare Workers pokud:

235- Potrebujete co nejnizsi latenci globalne

236- Chcete nejlevnejsi moznost ve velkém

237- Potrebujete schopnosti edge computingu

238- Cas cold startu je kriticky pro vas pripad pouziti

239~

240## Lze je kombinovat?

241~

242Rozhodne. Bezna architektura:

243~

244```mermaid

245graph TD

246 User --> CF[Cloudflare Workers\nEdge caching, routing, A/B tests]

247 CF --> Vercel[Vercel\nNext.js frontend + API routes]

248 Vercel --> Lambda[AWS Lambda\nHeavy processing, background jobs]

249 Lambda --> S3[S3 Storage]

250 Lambda --> DB[(Database)]

251```

252~

253- **Cloudflare Workers**: edge smerovani, cachovani, bezpecnost

254- **Vercel Functions**: frontendove API routy, SSR

255- **AWS Lambda**: tezke backendove zpracovani, planovane ulohy, pipeline udalosti

256~

257## Zaver

258~

259Serverless vyrazne dozral. V roce 2026 zavisi volba mezi AWS Lambda, Vercel Functions a Cloudflare Workers na vasem stacku a prioritach:

260~

261- **Nejjednodussi zkusenost vyvojare**: Vercel

262- **Nejvykonnejsi a nejflexibilnejsi**: AWS Lambda

263- **Nejlepsi vykon a ceny**: Cloudflare Workers

264~

265Vsechny tri jsou pripraveny na produkci a overeny v boji. Zacnete s tou, ktera odpovida vasemu soucasnemu stacku, a rozsirojte se podle rustu vasich potreb.

266~