Trigger and scope
CRITICAL: many subcommands have unintuitive paths (e.g. fastly domain create fails with 403, correct is fastly service domain create; logging is under fastly service logging; alerts under fastly service alert; rate limits under fastly service rate-limit).
Covers: services, backends, domains, VCL snippets, cache purging, Compute/WASM deploys, log streaming (S3/Datadog/Splunk/Kafka/25+ providers), NGWAF/WAF, TLS/mTLS, KV/config/secret stores, stats, alerts, rate limiting, ACLs, and auth tokens.
Fastly CLI OverviewPrerequisites
Requires the fastly CLI; API operations also need network access to Fastly.
For installation, see https://www.fastly.com/documentation/reference/cli/.
JSON examples also need jq; origin checks use curl and openssl.
Compute builds need the project's language toolchain and dependencies.
Use credentials already configured in the user's local CLI or environment.
If authentication is missing, have the user complete fastly auth login --sso locally or configure FASTLY_API_TOKEN outside chat.
Never ask for an API key in chat, print a token, or enable shell tracing on authenticated commands.
References
| Topic | File | Use when... |
|---|---|---|
| Authentication | auth.md | Login, stored tokens, service auth, CI/CD auth setup |
| Compute | compute.md | Building/deploying edge applications, local dev server |
| Services | services.md | Service CRUD, backends, domains, ACLs, dictionaries, VCL, purging, rate limiting |
| Logging | logging.md | Log streaming to S3, GCS, Datadog, Splunk, Kafka, 25+ providers |
| NGWAF | ngwaf.md | Next-Gen WAF workspaces, IP/country lists, rules, signals, thresholds, alerts |
| Notifications | notifications.md | Slack/PagerDuty/webhook integrations, audit log event mappings |
| Stats | stats.md | Which fastly stats subcommand takes which flag, and where the two flag sets diverge |
| Stores | stores.md | KV Stores, Config Stores, Secret Stores, resource links |
| TLS | tls.md | Platform TLS, Let's Encrypt subscriptions, custom certs, mutual TLS |
For endpoint choice, unit and window conventions and worked queries, use the fastly-stats skill.
Command Structure
fastly <command> <subcommand> [flags]
Top-Level Commands
| Category | Commands |
|---|---|
| Compute | compute - Build and deploy edge applications |
| Services | service - Manage CDN services, logging, backends, VCL, ACLs, purging |
| Security | ngwaf - Web application firewall |
| TLS | tls-subscription, tls-custom, tls-platform, tls-config - Certificate management |
| Storage | kv-store, config-store, secret-store - Edge data stores |
| Auth | auth - Login, stored tokens, active token output, revocation; auth-token (deprecated) |
| Info | stats, ip-list, pops, whoami - Information queries |
| Notify | integration - Notification destinations; audit-log event-mapping - Event triggers |
| Other | dashboard, domain, dns, apisecurity, products, object-storage, tools |
Global Flags
Available on most commands:
# Service targeting
--service-id SERVICE_ID # Target service by ID
--service-name NAME # Target service by name
-s SERVICE_ID # Short form
# Version targeting (version-scoped commands like `fastly service domain/backend/...`)
# NOTE: `fastly domain create` does NOT accept --version (it uses a different API)
--version VERSION # Specific version number
--version active # Currently active version
--version latest # Most recent version
--version staged # Currently staged version
# Authentication
--token TOKEN # API token or stored token name (use 'default' for default)
# Output (--json is per-command, not global)
--verbose # Detailed output
--quiet # Minimal output
# Automation
--accept-defaults # Accept default values
--auto-yes # Skip confirmations
--non-interactive # No prompts
Key Patterns
- Target by ID (
-s SERVICE_ID) or name (--service-name NAME) - Version targeting:
--version active,--version latest,--version staged, or--version N - Use
--autocloneto auto-clone locked versions - Use
--jsonfor scripted output,--non-interactive --accept-defaultsfor CI/CD - JSON field names vary by command; inspect output before writing
jqselectors. ActiveVersionshape varies; prefer--version active, or parse withjq -r '.ActiveVersion.Number // .ActiveVersion'- CLI version is
fastly version(notfastly --version) - POP/shield lookup is
fastly pops; it has nolistsubcommand and no--json; use theSHIELDcolumn value (not POPCODE) for--shield - Auth:
fastly auth login --ssoto login, or setFASTLY_API_TOKENenv var - For commands that need the active API token, use
$(fastly auth token); select a specific stored token with$(fastly auth token --token TOKEN_NAME) auth tokenrefuses terminal output, but agent-captured stdout may be non-terminal; never run it standalone or echo its result- Logging is under
service logging(e.g.fastly service logging s3 create) - Config: use
fastly config --locationto find the platform-specific CLI config file;fastly.tomlis the project manifest
Common Flag Examples
These are the flags that cause the most confusion. Copy-paste these patterns directly.
Autocloning (existing service versions)
# --autoclone automatically clones a locked version before making changes.
# Without it, you get "version is locked" errors and waste time cloning manually.
fastly service backend create --service-id $SID --version active --autoclone \
--name my-origin --address origin.example.com --port 443 --use-ssl
fastly service domain create --service-id $SID --version active --autoclone \
--name cdn.example.com
Pass --autoclone when creating, updating, or deleting backends, domains, snippets, VCL, conditions, headers, or other version-scoped resources on an existing service.
For a brand new service, configure the unlocked --version 1 without --autoclone, then validate and activate once, as shown in the new-service workflow below.
Boolean flags (--use-ssl, --use-ssl is NOT --use-ssl true)
# CORRECT - boolean flags are bare, no value
fastly service backend create --name origin --address example.com --port 443 --use-ssl
# WRONG - do not pass a value to boolean flags
fastly service backend create --name origin --address example.com --port 443 --use-ssl true
Other boolean flags that work the same way: --auto-yes, --non-interactive, --verbose, --quiet, --autoclone.
Domain creation (requires --name flag)
# CORRECT
fastly service domain create --service-id $SID --version active --autoclone --name cdn.example.com
# WRONG - domain is not a positional argument
fastly service domain create --service-id $SID --version active cdn.example.com
# WRONG - there is no -d flag
fastly service domain create --service-id $SID --version active -d cdn.example.com
Stats (historical and real-time)
# Historical stats by day for a date range (JSON output)
fastly stats historical --service-id $SID --by day \
--from "2026-02-01" --to "2026-03-01" --json
# Real-time stats (last second)
fastly stats realtime --service-id $SID --json
The --by flag accepts: day, hour, minute. The --from and --to flags use quoted date strings. Use --json for JSON output on stats commands.
Propagation Delays
Changes propagate across Fastly's network in seconds to minutes (up to 10 min for version activations, up to 5 min for TLS). Cache purges are 1-2 seconds. Retry with backoff when verifying changes.
New service activation sequence: After activating a brand new service, expect 500 "Domain Not Found" for 10-60 seconds while the domain propagates to edge POPs. This is normal — do not change configuration. Wait and retry. After version updates (e.g., fixing backend settings), allow 15-30 seconds for the new version to propagate.
KV Store Gotchas
- Link before use: A KV store must be linked to a service version before Compute code can access it. Use
fastly kv-store createthenfastly service resource-link create --resource-id STORE_ID --service-id $SID --version active --autoclone. - Eventual consistency: Read-after-write is eventually consistent. A key you just wrote may not be readable for a few seconds. Do not rely on immediate read-back in scripts; add a short delay or retry loop.
- Entry size limit: Individual KV store entries are limited to 25 MB. Plan accordingly for large values.
- Listing stores:
fastly kv-store listlists all stores on the account, not per-service. Usefastly service resource-link listto see which stores are linked to a given service.
Host Header Override Pattern
When the origin hostname differs from the desired Host header (e.g., origin is example.com but you want to send Host: download.example.com), use --override-host on the backend:
fastly service backend create --service-id $SID --version 1 \
--name my-origin --address example.com --port 443 --use-ssl \
--override-host download.example.com \
--ssl-cert-hostname example.com --ssl-sni-hostname example.com
The --override-host value is the Host header sent to the origin. The --ssl-cert-hostname and --ssl-sni-hostname must match the origin's TLS certificate (usually the --address value). Getting these backwards causes 503 errors.
Service List Completeness
When enumerating services (e.g., for bandwidth stats), use fastly service list --json.
The command follows API pagination internally and returns all pages unless you explicitly start from a later --page.
Services with zero traffic still appear in the list, so loop over every returned service ID instead of relying on stats APIs that omit zero-traffic services.
New VCL Service Setup Workflow
Use this sequence to stand up a new VCL caching service end-to-end. Each step includes a validation checkpoint.
-
Pre-flight — verify the origin responds and check its TLS certificate SANs:
curl -sI -H "Host: DESIRED_HOST" https://ORIGIN_ADDRESS/ echo | openssl s_client -connect ORIGIN_ADDRESS:443 -servername ORIGIN_ADDRESS 2>/dev/null | \ openssl x509 -noout -text | grep -A1 "Subject Alternative Name"Checkpoint: origin returns 200 and the backend
ssl-cert-hostnamematches the served cert. If no HTTPS SNI/cert combination validates but HTTP with that Host works, use--port 80or fix the origin cert; do not disable verification. -
Create service — note the service ID from the output:
fastly service create --name "my-service" --non-interactive -
Add domain + backend on version 1 (do NOT use
--autocloneor--version lateston a new service):fastly service domain create --service-id $SID --version 1 \ --name my-service.global.ssl.fastly.net fastly service backend create --service-id $SID --version 1 \ --name origin --address ORIGIN_ADDRESS --port 443 --use-ssl \ --override-host ORIGIN_ADDRESS \ --ssl-cert-hostname ORIGIN_ADDRESS --ssl-sni-hostname ORIGIN_ADDRESS -
Validate version before activating:
fastly service version validate --service-id $SID --version 1Checkpoint: validation returns success (no missing domain/backend errors).
-
Activate:
fastly service version activate --service-id $SID --version 1 -
Verify propagation — wait 15-30s, then test with GET (not HEAD):
curl -sS -D - -o /dev/null https://my-service.global.ssl.fastly.net/ | head -1Checkpoint: 200 OK. If 500 "Domain Not Found", wait and retry (normal for 10-60s). If 503, check backend SSL settings.
See services.md for advanced workflows (custom domains with TLS, host header overrides, live service updates).
Troubleshooting
See troubleshooting.md for the full list. Key pitfalls are covered inline above: SSL hostname flags (see Host Header Override Pattern), boolean flags and domain --name (see Common Flag Examples), --autoclone (see Key Patterns), and token safety (see Key Patterns).