---
title: fastly service backend update
summary: Update a backend on a Fastly service version
url: https://www.fastly.com/documentation/reference/cli/service/backend/update
---

Update a backend on a Fastly service version

## Flags

| Flag | Description | Required | Default |
|------|-------------|----------|----------|
| `--version` | 'latest', 'active', 'staged', or the number of a specific Fastly service version | Yes | - |
| `--name` | backend name | Yes | - |
| `--address` | A hostname, IPv4, or IPv6 address for the backend | No | - |
| `--autoclone` | If the selected service version is not editable, clone it and use the clone. | No | - |
| `--auto-loadbalance` | Whether or not this backend should be automatically load balanced | No | - |
| `--between-bytes-timeout` | How long to wait between bytes in milliseconds | No | - |
| `--comment` | A descriptive note | No | - |
| `--connect-timeout` | How long to wait for a timeout in milliseconds | No | - |
| `--first-byte-timeout` | How long to wait for the first bytes in milliseconds | No | - |
| `--healthcheck` | The name of the healthcheck to use with this backend | No | - |
| `--max-conn` | Maximum number of connections | No | - |
| `--max-use` | Maximum number of requests allowed over a single, pooled HTTP keepalive connection to this backend; 0 is treated as unlimited. | No | - |
| `--max-lifetime` | Maximum time from creation (in milliseconds) that a pooled HTTP keepalive connection will be eligible for reuse; 0 is treated as unlimited. | No | - |
| `--max-tls-version` | Maximum allowed TLS version on SSL connections to this backend | No | - |
| `--min-tls-version` | Minimum allowed TLS version on SSL connections to this backend | No | - |
| `--new-name` | New backend name | No | - |
| `--no-ssl-check-cert` | Skip checking SSL certs | No | - |
| `--override-host` | The hostname to override the Host header | No | - |
| `--port` | Port number of the address | No | - |
| `--prefer-ipv6` | Prefer IPv6 connections | No | - |
| `--request-condition` | condition, which if met, will select this backend during a request | No | - |
| `--service-id` | Service ID (falls back to FASTLY_SERVICE_ID, then fastly.toml) | No | - |
| `--service-name` | The name of the service | No | - |
| `--shield` | The shield POP designated to reduce inbound load on this origin by serving the cached data to the rest of the network | No | - |
| `--ssl-ca-cert` | CA certificate attached to origin | No | - |
| `--ssl-cert-hostname` | Overrides ssl_hostname, but only for cert verification. Does not affect SNI at all. | No | - |
| `--ssl-check-cert` | Be strict on checking SSL certs | No | - |
| `--ssl-ciphers` | List of OpenSSL ciphers (https://www.openssl.org/docs/man1.0.2/man1/ciphers) | No | - |
| `--ssl-client-cert` | Client certificate attached to origin | No | - |
| `--ssl-client-key` | Client key attached to origin | No | - |
| `--ssl-sni-hostname` | Overrides ssl_hostname, but only for SNI in the handshake. Does not affect cert validation at all. | No | - |
| `--tcp-ka-enabled` | Enable TCP keepalive probes [true, false] | No | - |
| `--tcp-ka-interval` | Configure how long to wait between sending each TCP keepalive probe. | No | - |
| `--tcp-ka-probes` | Configure how many unacknowledged TCP keepalive probes to send before considering the connection dead. | No | - |
| `--tcp-ka-time` | Configure how long to wait after the last sent data before sending TCP keepalive probes. | No | - |
| `--http-ka-time` | Configure how long to keep idle HTTP keepalive connections in the connection pool. | No | - |
| `--use-ssl` | Whether or not to use SSL to reach the backend | No | - |
| `--weight` | Weight used to load balance this backend against others | No | - |

## Global options

| Flag | Description | Required | Default |
|------|-------------|----------|----------|
| `--help` | Show context-sensitive help. | No | - |
| `--accept-defaults` | Accept default options for all interactive prompts apart from Yes/No confirmations | No | - |
| `--auto-yes` | Answer yes automatically to all Yes/No confirmations. This may suppress security warnings | No | - |
| `--debug-mode` | Print API request and response details (NOTE: can disrupt the normal CLI flow output formatting) | No | - |
| `--non-interactive` | Do not prompt for user input - suitable for CI processes. Equivalent to --accept-defaults and --auto-yes | No | - |
| `--quiet` | Silence all output except direct command output. This won't prevent interactive prompts (see: --accept-defaults, --auto-yes, --non-interactive) | No | - |
| `--token` | Fastly API token, or name of a stored auth token (use 'default' for the default token). Falls back to FASTLY_API_TOKEN env var | No | - |
| `--verbose` | Verbose logging | No | - |