1# Cron Triggers Configuration
2 
3## wrangler.jsonc
4 
5```jsonc
6{
7  "$schema": "./node_modules/wrangler/config-schema.json",
8  "name": "my-cron-worker",
9  "main": "src/index.ts",
10  "compatibility_date": "2025-01-01", // Use current date for new projects
11  
12  "triggers": {
13    "crons": [
14      "*/5 * * * *",     // Every 5 minutes
15      "0 */2 * * *",     // Every 2 hours
16      "0 9 * * MON-FRI", // Weekdays at 9am UTC
17      "0 2 1 * *"        // Monthly on 1st at 2am UTC
18    ]
19  }
20}
21```
22 
23## Green Compute (Beta)
24 
25Schedule crons during low-carbon periods for carbon-aware execution:
26 
27```jsonc
28{
29  "name": "eco-cron-worker",
30  "triggers": {
31    "crons": ["0 2 * * *"]
32  },
33  "placement": {
34    "mode": "smart"  // Runs during low-carbon periods
35  }
36}
37```
38 
39**Modes:**
40- `"smart"` - Carbon-aware scheduling (may delay up to 24h for optimal window)
41- Default (no placement config) - Standard scheduling (no delay)
42 
43**How it works:**
44- Cloudflare delays execution until grid carbon intensity is lower
45- Maximum delay: 24 hours from scheduled time
46- Ideal for batch jobs with flexible timing requirements
47 
48**Use cases:** 
49- Nightly data processing and ETL pipelines
50- Weekly/monthly report generation
51- Database backups and maintenance
52- Analytics aggregation
53- ML model training
54 
55**Not suitable for:** 
56- Time-sensitive operations (SLA requirements)
57- User-facing features requiring immediate execution
58- Real-time monitoring and alerting
59- Compliance tasks with strict time windows
60 
61## Environment-Specific Schedules
62 
63```jsonc
64{
65  "name": "my-cron-worker",
66  "triggers": {
67    "crons": ["0 */6 * * *"]  // Prod: every 6 hours
68  },
69  "env": {
70    "staging": {
71      "triggers": {
72        "crons": ["*/15 * * * *"]  // Staging: every 15min
73      }
74    },
75    "dev": {
76      "triggers": {
77        "crons": ["*/5 * * * *"]  // Dev: every 5min
78      }
79    }
80  }
81}
82```
83 
84## Schedule Format
85 
86**Structure:** `minute hour day-of-month month day-of-week`
87 
88**Special chars:** `*` (any), `,` (list), `-` (range), `/` (step), `L` (last), `W` (weekday), `#` (nth)
89 
90## Managing Triggers
91 
92**Remove all:** `"triggers": { "crons": [] }`  
93**Preserve existing:** Omit `"triggers"` field entirely
94 
95## Deployment
96 
97```bash
98# Deploy with config crons
99npx wrangler deploy
100 
101# Deploy specific environment
102npx wrangler deploy --env production
103 
104# View deployments
105npx wrangler deployments list
106```
107 
108**⚠️ Changes take up to 15 minutes to propagate globally**
109 
110## API Management
111 
112**Get triggers:**
113```bash
114curl "https://api.cloudflare.com/client/v4/accounts/{account_id}/workers/scripts/{script_name}/schedules" \
115  -H "Authorization: Bearer {api_token}"
116```
117 
118**Update triggers:**
119```bash
120curl -X PUT "https://api.cloudflare.com/client/v4/accounts/{account_id}/workers/scripts/{script_name}/schedules" \
121  -H "Authorization: Bearer {api_token}" \
122  -H "Content-Type: application/json" \
123  -d '{"crons": ["*/5 * * * *", "0 2 * * *"]}'
124```
125 
126**Delete all:**
127```bash
128curl -X PUT "https://api.cloudflare.com/client/v4/accounts/{account_id}/workers/scripts/{script_name}/schedules" \
129  -H "Authorization: Bearer {api_token}" \
130  -H "Content-Type: application/json" \
131  -d '{"crons": []}'
132```
133 
134## Combining Multiple Workers
135 
136For complex schedules, use multiple workers:
137 
138```jsonc
139// worker-frequent.jsonc
140{
141  "name": "data-sync-frequent",
142  "triggers": { "crons": ["*/5 * * * *"] }
143}
144 
145// worker-daily.jsonc
146{
147  "name": "reports-daily",
148  "triggers": { "crons": ["0 2 * * *"] },
149  "placement": { "mode": "smart" }
150}
151 
152// worker-weekly.jsonc
153{
154  "name": "cleanup-weekly",
155  "triggers": { "crons": ["0 3 * * SUN"] }
156}
157```
158 
159**Benefits:**
160- Separate CPU limits per worker
161- Independent error isolation
162- Different Green Compute policies
163- Easier to maintain and debug
164 
165## Validation
166 
167**Test cron syntax:**
168- [crontab.guru](https://crontab.guru/) - Interactive validator
169- Wrangler validates on deploy but won't catch logic errors
170 
171**Common mistakes:**
172- `0 0 * * *` runs daily at midnight UTC, not your local timezone
173- `*/60 * * * *` is invalid (use `0 * * * *` for hourly)
174- `0 2 31 * *` only runs on months with 31 days
175 
176## See Also
177 
178- [README.md](./README.md) - Overview, quick start
179- [api.md](./api.md) - Handler implementation
180- [patterns.md](./patterns.md) - Multi-cron routing examples
181