Tunnel for developers and CTOs
Expose localhost to the internet, without touching your router
One outbound connection, a public HTTPS address, and nothing open on your network.
Free tier on every product. No card.
To expose localhost to the internet you usually have two choices: open a port on your router and deal with dynamic IPs and certificates, or deploy somewhere. SyncYak Tunnel is the third way. Run syncyak http 3000 and your local server answers on a public HTTPS address in seconds, with a valid certificate and nothing opened on your network.
Because the connection starts from your machine, it works on any network that allows outbound HTTPS: a home router, a corporate firewall, a phone hotspot. When you stop the CLI, the address stops answering.
How it works
Expose localhost in three steps
Install the syncyak CLI
Download it for Windows, macOS or Linux from your Tunnel console, then save your token once with syncyak config add-authtoken.
Forward a port
Run syncyak http 3000. The CLI prints a public HTTPS address that forwards to http://localhost:3000.
Share it or keep it
Send the address to anyone, paste it into a webhook setting, or reserve a name so it stays the same tomorrow.
Share localhost with a public URL, safely
Exposing a development server means anyone with the link can reach it. Keep that in check: use a random name for short sessions, add --basic-auth "user:a-long-password" so visitors must log in, and keep the inspector open to see every request that arrives.
Only the port you name is forwarded. Your other services, your file system and the rest of your network stay where they are.
- Basic auth with an 8 to 128 character password
- Every request and response visible in the inspector
- Stop with Ctrl+C or from the dashboard
A public URL for localhost that frameworks accept
Many frameworks reject requests whose Host header they do not recognise. The --host-header=rewrite flag rewrites it to localhost:<port>, so a Vite or webpack dev server, a Rails app or a Django project with a strict ALLOWED_HOSTS works without configuration changes.
Use cases
When to expose localhost
A demo without a deploy
Walk a client through a feature on the branch that exists only on your laptop.
A device on your network
Forward 192.168.1.20:8080 to give a printer dashboard, a Raspberry Pi or a VM a public address for a while.
Callbacks from third parties
Payment providers, OAuth flows and CRMs need a public HTTPS URL to call you back.
What you get with Tunnel
Tunnel is the tunnel product of SyncYak, one account that also covers email parsing, a mailbox API, CRM sync and error tracking. The CLI runs on Windows, macOS and Linux, keeps reconnecting with backoff when your network drops, and keeps a reserved name for as long as you hold it.
Free gives you 1 tunnel with a random name and 2 GB of traffic a month. Hobby is $8 a month for 3 tunnels, 3 reserved names and 25 GB; traffic past your plan can continue at $0.05 per GB up to a cap you set.
- syncyak http 3000 for a random HTTPS address, or a reserved name such as myapp.syncyak.live
- HTTPS to your local app, another machine on your network, or a local HTTPS server
- --host-header=rewrite for Vite, webpack dev server and Django, --basic-auth to keep visitors out
- A request inspector that keeps traffic for 24 hours on Free and longer on paid plans
Frequently asked questions
Something else? Write to contact@syncyak.com and a person answers.
Do I need a static IP to expose localhost?
No. The address belongs to the tunnel, not to your network, so it works on dynamic IPs and behind NAT.
Can I protect the exposed site with a password?
Yes. Start the tunnel with --basic-auth "name:password" and visitors must log in before any request reaches your app.
Does the address stay the same?
A random address lasts while the tunnel runs (and 10 minutes after a disconnect). Reserved names on paid plans stay yours until you release them.
Is there a free plan for Tunnel?
Yes. Tunnel has a free tier with no card and no end date: 1 tunnel, random subdomain, 2 gb a month. Paid tiers start at $8 a month, and you can move up or down at any time.
Can I use the other SyncYak products on the same account?
Yes. Email parsing, the mailbox API, CRM sync, error tracking and tunnels share one login, one team, one API key system and one bill. Each product has its own tier, so you only pay more for the one that grows.
Related
Related solutions
Start with Tunnel free
1 tunnel, Random subdomain, 2 GB a month, free every month. Set up in minutes, and add the other SyncYak products on the same account when you need them.
Free tier on every product. No card.