Callbook AI

AI collections agency for lenders: agents that locate, contact and negotiate with borrowers over voice, SMS and email, classify accounts by ability and willingness to pay, offer payment plans and route disputes to people, measured against the lender's current collections results.

StageUndisclosed

Founded2025

HeadquartersSan Francisco, USA

StatusPrivate

Founded — ycombinator.com · 19 Oct 2026

callbook.ai

Product

Selected offerings — the AI products recorded here, not the vendor's full catalogue.

Callbook AI AI agent

AI agents that run collections for lenders: they locate each borrower, contact them by phone, SMS and email in one continuous conversation, classify accounts by ability and willingness to pay, negotiate payment plans, send payment links, and hand disputes or hardship cases to people; sold by contact with no published price.

Similar products 70

No sourced competitor yet: no filing, vendor document or measured-market report read so far names a rival for this company, so none is asserted. The companies below are the closest by what their products do.

How this list is ranked ↗

All 70Shared product type 42Same company status 47

LunaBillUndisclosedCallbook AI and LunaBill both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare E

EvergroveUndisclosedCallbook AI and Evergrove both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare A

AllooviumUndisclosedCallbook AI and Alloovium both list voice agent; scale not recorded for either; ships application rather than the same layer.2 of 2 capabilitiesDifferent layerCompare D

DeryaUndisclosedCallbook AI and Derya both list voice agent; scale not recorded for either.1 of 2 capabilitiesShared product typeCompare AH

Assort HealthLate-stageCallbook AI and Assort Activate both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare B

BernardUndisclosedCallbook AI and Bernard both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare E

EvenUpLate-stageCallbook AI and EvenUp Communication Agents both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare E

EliteUndisclosedCallbook AI and Elite Health both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare C

CerencePublicCallbook AI and Dealer Assist Agent both list voice agent; Callbook AI's scale not recorded.1 of 2 capabilitiesShared product typeCompare HA

Hippocratic AILate-stageCallbook AI and AI Physician Front Door both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare SA

SoundHound AIPublicCallbook AI and Employee Assist both list voice agent; Callbook AI's scale not recorded.1 of 2 capabilitiesShared product typeCompare R

RibbonEarly-stageCallbook AI and Ribbon AI Interviewer both list voice agent; scale not recorded for either.1 of 2 capabilitiesShared product typeCompare S

ScreenedUndisclosedCallbook AI and Ryan both list voice agent; scale not recorded for either.1 of 2 capabilitiesShared product typeCompare C

CarSignalUndisclosedCallbook AI and CarSignal both list voice agent; scale not recorded for either; ships application rather than the same layer.2 of 2 capabilitiesDifferent layerCompare F

ForethoughtAcquiredCallbook AI and Forethought Voice both list voice agent; Callbook AI's scale not recorded; Forethought is acquired, with no independent scale.2 of 2 capabilitiesShared product typeCompare A

AlexEarly-stageCallbook AI and AI Interviewer both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare FL

Funnel LeasingUndisclosedCallbook AI and Fenix both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare P

PolyAIUndisclosedCallbook AI and PolyAI dialog agents both list voice agent; scale not recorded for either.1 of 2 capabilitiesShared product typeCompare H

HaptikAcquiredCallbook AI and Voice AI Agents both list voice agent; Callbook AI's scale not recorded; Haptik is acquired, with no independent scale.2 of 2 capabilitiesShared product typeCompare S

ServiceNowPublicCallbook AI and AI Agents both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare S

SalesforcePublicCallbook AI and Casey, the Help Agent both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare P

PhenomLate-stageCallbook AI and Voice Screening Agent both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare SI

Shire IntelligenceUndisclosedCallbook AI and Shire both list voice agent; scale not recorded for either; ships application rather than the same layer.2 of 2 capabilitiesDifferent layerCompare LL

Listen LabsLate-stageCallbook AI and Listen both list voice agent; scale not recorded for either; ships application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare F

FinAcquiredCallbook AI and Fin Voice both list voice agent; Callbook AI's scale not recorded; Fin is acquired, with no independent scale.2 of 2 capabilitiesShared product typeCompare C

CartesiaEarly-stageCallbook AI and Managed Agents both list voice agent; scale not recorded for either; ships API service and agent platform rather than the same layer.1 of 2 capabilitiesDifferent layerCompare 11

11xEarly-stageCallbook AI and Julian both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare FR

Furhat RoboticsUndisclosedCallbook AI and FurhatAI Creator both list voice agent; scale not recorded for either; ships application, platform and 1 more rather than the same layer.1 of 2 capabilitiesDifferent layerCompare B

BrightHireEarly-stageCallbook AI and BrightHire Screen both list voice agent; scale not recorded for either.1 of 2 capabilitiesShared product typeCompare AS

AI ScreenrUndisclosedCallbook AI and AI Screenr both list voice agent; scale not recorded for either; ships application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare Y

Yellow.aiUndisclosedCallbook AI and Nexus Vox both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare S

Sona8UndisclosedCallbook AI and Sona8 both list voice agent; scale not recorded for either; ships application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare Z

ZoomPublicCallbook AI and Zoom Virtual Agent Receptionist both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare D

DecagonLate-stageCallbook AI and Decagon both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare C

CrescendoEarly-stageCallbook AI and Crescendo Concierge both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare P

ParloaLate-stageCallbook AI and Parloa AMP both list voice agent; Callbook AI's scale not recorded.1 of 2 capabilitiesShared product typeCompare L

LivePersonAcquiredCallbook AI and LivePerson Voice AI both list voice agent; Callbook AI's scale not recorded; LivePerson is acquired, with no independent scale.2 of 2 capabilitiesShared product typeCompare S

SpeakLate-stageCallbook AI and Speak for Business both list voice agent; Callbook AI's scale not recorded; ships application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare N

NiCEPublicCallbook AI and AI Agents for Self-Service both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare G

GenesysUndisclosedCallbook AI and Genesys Cloud CX both list voice agent; Callbook AI's scale not recorded; Genesys's scale not comparable: only a revenue estimate, no market cap or valuation.2 of 2 capabilitiesShared product typeCompare S

SierraLate-stageCallbook AI and Sierra both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare O

OraclePublicCallbook AI and Oracle Digital Assistant both list voice agent; Callbook AI's scale not recorded; ships API service, agent platform and 6 more rather than the same layer.2 of 2 capabilitiesDifferent layerCompare T

TwilioPublicCallbook AI and Twilio Conversations both list voice agent; Callbook AI's scale not recorded; ships API service, application and 3 more rather than the same layer.2 of 2 capabilitiesDifferent layerCompare K

Kore.aiLate-stageCallbook AI and AI for Service both list voice agent; scale not recorded for either; ships agent platform and application rather than the same layer.2 of 2 capabilitiesDifferent layerCompare AL

Aleph LabUndisclosedCallbook AI and Aleph Kids both list voice agent; scale not recorded for either; ships application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare SC

Spanish ChatUndisclosedCallbook AI and Maya both list voice agent; scale not recorded for either; ships application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare RA

Retell AIUndisclosedCallbook AI and Retell AI Voice Agents both list voice agent; scale not recorded for either; ships agent platform rather than the same layer.1 of 2 capabilitiesDifferent layerCompare BA

Bland AIEarly-stageCallbook AI and Bland both list voice agent; scale not recorded for either; ships API service and agent platform rather than the same layer.1 of 2 capabilitiesDifferent layerCompare C

CognigyAcquiredCallbook AI and Cognigy Voice Gateway both list voice agent; Callbook AI's scale not recorded; Cognigy is acquired, with no independent scale; ships agent platform, application and 2 more rather than the same layer.2 of 2 capabilitiesDifferent layerCompare X

Xiao-iPublicCallbook AI and Xiao-i cognitive intelligence platform both list voice agent; Callbook AI's scale not recorded; Xiao-i's scale not comparable: only a revenue estimate, no market cap or valuation; ships application and platform rather than the same layer.1 of 2 capabilitiesDifferent layerCompare A

ApplePublicCallbook AI and Siri AI both list voice agent; Callbook AI's scale not recorded; ships application and developer tool rather than the same layer.1 of 2 capabilitiesDifferent layerCompare R

RespeecherEarly-stageCallbook AI and Respeecher Space both list voice agent; scale not recorded for either; ships API service and application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare TA

Talkio AIUndisclosedCallbook AI and Talkio AI both list voice agent; scale not recorded for either; ships application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare Y

YandexPublicCallbook AI and Yandex SpeechKit both list voice agent; Callbook AI's scale not recorded; ships API service, application and 2 more rather than the same layer.1 of 2 capabilitiesDifferent layerCompare D

DuolingoPublicCallbook AI and Duolingo Max both list voice agent; Callbook AI's scale not recorded; ships application rather than the same layer.1 of 2 capabilitiesDifferent layerCompare L

LATOUndisclosedCallbook AI and LATO both list voice agent; scale not recorded for either.1 of 2 capabilitiesShared product typeCompare IA

Inworld AIUndisclosedCallbook AI and Realtime API both list voice agent; scale not recorded for either; ships API service, infrastructure service and 2 more rather than the same layer.1 of 2 capabilitiesDifferent layerCompare M

monday.comPublicCallbook AI and monday Agent Factory both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare ST

SK TelecomPublicCallbook AI and NUGU bizcall both list voice agent; scale not recorded for either; ships application and infrastructure service rather than the same layer.1 of 2 capabilitiesDifferent layerCompare M

ManatalUndisclosedCallbook AI and Manatal AI Interviewer both list voice agent; scale not recorded for either.1 of 2 capabilitiesShared product typeCompare S

SynthesiaLate-stageCallbook AI and Survey Sessions both list voice agent; Callbook AI's scale not recorded.1 of 2 capabilitiesShared product typeCompare R

RingCentralPublicCallbook AI and AI Receptionist both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare I

InCruiterUndisclosedCallbook AI and IncScreen both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare E

eGainPublicCallbook AI and eGain AI Agent both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare D

DiligenceSquaredUndisclosedCallbook AI and DiligenceSquared both list voice agent; scale not recorded for either; ships platform rather than the same layer.1 of 2 capabilitiesDifferent layerCompare C

CiscoPublicCallbook AI and Webex AI Agent both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare R

RasaEarly-stageCallbook AI and Rasa Voice both list voice agent; scale not recorded for either; ships agent platform, application and 1 more rather than the same layer.1 of 2 capabilitiesDifferent layerCompare F

FirefliesUndisclosedCallbook AI and Fireflies AI Voice Agents both list voice agent; scale not recorded for either.2 of 2 capabilitiesShared product typeCompare F

FreshworksPublicCallbook AI and Freshcaller both list voice agent; Callbook AI's scale not recorded.2 of 2 capabilitiesShared product typeCompare I

InkboxUndisclosedCallbook AI and Inkbox both list voice agent; scale not recorded for either; ships infrastructure service rather than the same layer.1 of 2 capabilitiesDifferent layerCompare

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Closest alternatives are pairs a vendor page itself compares. Similar products are matched from what each product does; nothing in that group is asserted as a rivalry.