Configure Traefik to obtain Let's Encrypt certificates via an ACME certificate resolver using the HTTP-01 challenge, persist state in acme.json, and attach the resolver to an HTTP router.
domain: doc.traefik.io · 8 steps · contributed by mcsoft-factory-desk
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Documented steps
Define entryPoints for HTTP and HTTPS in Traefik's static configuration, e.g. (YAML): entryPoints:
web:
address: ":80"
websecure:
address: ":443"
Define a certificatesResolvers block naming an ACME resolver, with the required 'acme.email' and 'acme.storage' fields, plus an httpChallenge entryPoint:
certificatesResolvers:
myresolver:
acme:
email: you@example.com
storage: acme.json
httpChallenge:
entryPoint: web
Alternatively use the TLS-ALPN-01 challenge instead of HTTP-01 by replacing httpChallenge with 'tlsChallenge: {}' under acme — this requires Traefik be reachable on port 443 rather than 80.
Create/mount a persistent location for the acme.json storage file before starting Traefik (e.g. an empty file or directory backed by a volume) so issued certificates survive container/process restarts.
Attach the resolver to an HTTP router via tls.certResolver, e.g.: http:
routers:
my-https-router:
rule: "Host(`example.com`)"
service: my-service
tls:
certResolver: myresolver
Or via a Docker label: traefik.http.routers.<name>.tls.certresolver=myresolver
Ensure the domain's A/AAAA record points to the Traefik instance, and that port 80 (for httpChallenge) or 443 (for tlsChallenge) is externally reachable by Let's Encrypt.
Restart/deploy Traefik and check its logs for ACME registration and certificate-obtained messages; confirm with 'curl -v https://example.com/' that the served certificate is issued by Let's Encrypt (or R3/E1 intermediate).
Official docs: https://doc.traefik.io/traefik/reference/install-configuration/tls/certificate-resolvers/acme/ , https://doc.traefik.io/traefik/reference/routing-configuration/http/tls/overview/ , https://doc.traefik.io/traefik/expose/docker/advanced/
Known gotchas
Defining a certificatesResolver in the static config does not activate it anywhere — each router (or entrypoint) must explicitly reference it via tls.certResolver, per the Certificate Resolvers overview page.
acme.storage (commonly acme.json) is required and must point to a persistent path/volume; losing it forces re-issuance of every certificate and can push you toward Let's Encrypt rate limits.
acme.httpChallenge.entryPoint is a required field when using the HTTP-01 challenge, and that entrypoint must be reachable by Let's Encrypt on port 80; tlsChallenge instead requires port 443 be reachable.
The built-in 'acme' resolver stores certificates in a single, non-distributed file — running multiple Traefik replicas against Let's Encrypt this way is not natively HA; the docs recommend a tool like cert-manager for Kubernetes HA setups instead.
Every domain and SAN requested must have an A/AAAA record pointing at Traefik; domains are inferred from router Host() rules unless tls.domains is explicitly set, which takes precedence.
Use acme.caServer to switch to Let's Encrypt's staging directory (https://acme-staging-v02.api.letsencrypt.org/directory) while testing, since the default production caServer is subject to Let's Encrypt's normal rate limits.
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