SSL/TLS · Rate Limits

Ssl Tls Rate Limits

Multi-vendor category covering ACME and CA-issuance APIs. Let's Encrypt publishes concrete per-account, per-IP, and per-domain limits on the ACME v2 endpoint; DigiCert and Sectigo gate API throughput per partner contract and do not publish numeric per-second limits. Numbers below are sourced from Let's Encrypt's public rate-limit documentation.

Ssl Tls Rate Limits is the machine-readable rate-limit profile for SSL/TLS on the APIs.io network, in the API Commons Rate Limits shape.

It captures 7 rate-limit definitions, measuring certificates, accounts, orders, failures, and varies.

Limit state is signalled in the retryAfter response header, and an exhausted limit returns HTTP 429.

This profile was written by API Evangelist and has not been verified against a page the provider published; treat every limit as unconfirmed until a dated transcription replaces it.

The profile also includes 3 backoff/retry policies defined and response codes documented for throttled and rateLimited.

Tagged areas include SSL/TLS, TLS, Certificates, PKI, and Certificate Authority.

7 Limits Exhausted: HTTP 429 retryAfter
Method: generated, dated 2026-05-05.
Written by API Evangelist on 2026-05-05 and not verified against a page the provider published. Treat every limit as unconfirmed until a dated transcription replaces it.
View Source
SSL/TLSTLSCertificatesPKICertificate AuthorityRate Limiting

Limits

Let's Encrypt - Certificates per Registered Domain registered-domain
certificates · week
50
Refills at 1 certificate per 202 minutes. Override available via Let's Encrypt rate-limit override form.
Let's Encrypt - Duplicate Certificates identifier-set
certificates · week
5
Same exact set of identifiers; refills at 1 certificate per 34 hours.
Let's Encrypt - New Accounts per IP IP
accounts · 3h
10
Refills at 1 account per 18 minutes. No overrides available.
Let's Encrypt - New Orders per Account account
orders · 3h
300
Refills at 1 order per 36 seconds. Overrides available upon request.
Let's Encrypt - Failed Validations per Account per Identifier account/identifier
failures · hour
5
Refills at 1 per identifier every 12 minutes. No overrides available.
DigiCert Services API account/contract
varies
per partner contract; not publicly documented
DigiCert gates API throughput through the partner agreement; consult your account team.
Sectigo Certificate Manager API account/contract
varies
per partner contract; not publicly documented
Sectigo enforces throughput per Cert Manager license; consult your account team.

Policies

ACME Backoff
Let's Encrypt returns 429 with a Retry-After header (sometimes embedded in the error message as 'retry after '); ACME clients (certbot, lego, acme.sh) honor this automatically and retry at the indicated time.
Staging Environment First
Let's Encrypt strongly recommends developing against the staging endpoint (acme-staging-v02.api.letsencrypt.org) where rate limits are much higher, before pointing automation at production.
Override by Request
New-orders-per-account and certificates-per-registered-domain caps can be raised via Let's Encrypt's public rate-limit override form for organizations with documented legitimate need. Account-per-IP and failed-validation caps cannot be overridden.

Sources

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