Bland + SIP

Bring your carrier or PBX to Bland over encrypted SIP and put 200ms voice agents on your own numbers, with a guided wizard, DIDs, and transfers both ways.

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What Bland does inside SIP.

200ms agents on your own numbers.

Bland owns the voice stack end to end, from speech recognition to the language model to speech, so agents on your trunk respond in 200 milliseconds and call data never touches a third-party AI provider.

A wizard that probes your endpoint.

Enter a hostname, IP, or SIP URI. Discovery resolves DNS, probes ports over UDP, TCP, and TLS, and detects your PBX, codecs, and the transport to use.

Numbers, DIDs, and extensions.

Attach E.164 numbers and non-E.164 identities like extension 2001 to a trunk, up to 100 at a time. Each one inherits the trunk's endpoint and authentication.

Transfers back to your PBX.

A Transfer Call node can send the caller to a DID, extension, or SIP URI: hand off with SIP REFER, have Bland send a new INVITE, or run a warm transfer.

Encrypted signaling and media.

Every connection is encrypted: signaling over TLS on port 5061 and media over SRTP, from static regional edges in the US, Canada, Asia-Pacific, and Europe.

Failover, codecs, and alerts.

Set primary, secondary, and tertiary servers with automatic failover, order codecs from PCMU to G.729, and alert by email, SMS, or webhook when a trunk degrades.

How it deploys.

Get SIP enabled.
Ask your Bland team to turn on SIP for your organization, then open Dispatch, then Phone numbers, then the SIP tab at All agents.
Run the setup wizard.
Click Add trunk, enter your provider endpoint, and let discovery recommend the port, transport, and system.
Open your firewall and pick auth.
Allow-list Bland's signaling and media IPs for your region, then choose IP-based or registration-based authentication.
Attach numbers and test.
Attach your numbers and DIDs, press Test connection, and place a call with a trunk number as the from value.

Our FDE team scopes the integration, maps Bland to your stack, and stays on through go-live. Enterprise deployments go live in 30 days.

Talk to an FDE

Drop Bland into your editor.

MCP server runs in Claude Code, Cursor, and any MCP-aware editor. Or hit the REST API directly.

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curl -X POST https://api.bland.ai/v1/calls \
  -H "Authorization: $BLAND_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "+14155552120",
    "task": "Qualify refi lead",
    "voice": "june"
  }'

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Frequently asked questions.

Can I connect my own SIP trunk to an AI voice agent?

Yes. Bland supports inbound and outbound SIP. Create a trunk with the setup wizard or the API, attach your numbers and DIDs, and calls from your carrier or PBX are answered by a Bland agent, or placed out through your provider.

What ports and IPs does Bland SIP use?

Signaling is always encrypted, over TLS on port 5061. Media uses SRTP over UDP ports 16384 to 32768 on a separate set of media IPs. Allow-list both sets for your region; the IPs are static.

Can the agent transfer a caller back to my PBX?

Yes. A Transfer Call node can target a DID, an extension, or a SIP URI on your trunk. Choose a SIP REFER hand-off, a new INVITE from Bland, or a warm transfer that briefs the person who answers before the caller joins.

Can I pass customer data into a SIP call?

Yes. Create an inbound session with request data through the Bland API, then send its token as the x-bland-session-id SIP header on the call. The variables are available to the agent when it answers. Outbound header mappings carry call variables on transfers.

Can I port my phone numbers to Bland?

Yes. The porting wizard checks portability, collects Letter of Authorization details and proof of ownership, and submits the request. Ports typically take 7 to 14 business days, and ported numbers are registered as Bland inbound numbers automatically.

Which PBXs and carriers work with Bland SIP?

Any standard SIP endpoint. The wizard has guided entries for Vonage, Asterisk and FreePBX, 3CX, Cisco UCM and CUBE, RingCentral, and Microsoft Teams through a certified SBC, and discovery detects Asterisk, FreeSWITCH, Kamailio, 3CX, and Cisco.