Both run AI-led interviews. Strella ships a voice-only call interface for enterprise research teams. Diaform lets respondents type or talk, runs mid-interview automations, and publishes its pricing.
14-day free trial · No demo required
Target buyer
SaaS product, CS, marketing, and founder teams running cross-functional research without a dedicated researcher on staff.
Enterprise UX research teams with dedicated researchers, formal study cycles, and procurement-driven buying.
Input mode
Respondents type or speak, switching freely per question. Works in any environment, on any device, no microphone required.
Voice-only call interface. Respondents speak into a mic; ambient noise can interrupt the AI mid-question. No way to type if they prefer or can't talk right now.
Sensitive or private topics
Text mode lets respondents answer in private, useful for compensation, performance, or anything they wouldn't say aloud.
Voice-first design pushes everyone to speak, which third-party reviews note feels less natural for emotional or sensitive topics.
Mobile and on-the-go respondents
Works in any browser on phone, tablet, or desktop. Text mode is friction-free for respondents commuting, working, or in shared spaces.
Browser-based and voice-first. Mobile respondents need a quiet space and a working mic to participate, which limits when and where they can complete the session.
Mid-interview automations
13 topic + 5 sentiment triggers fire actions in flow: alert Slack, capture an email, offer a discount, book a meeting, redirect to a save call.
Strong synthesis after the fact, but no in-flow AI actions that fire mid-conversation based on what the respondent says.
Save-offer / discount actions
Detects churn risk or price friction mid-interview and can offer a discount code or schedule a CS save call. Converts at-risk users back.
Built for research insight, not retention recovery. No native save-offer or discount-trigger workflow inside the interview.
Pricing transparency
Pro $89/mo ($74/mo annual). Business $149/mo ($124/mo annual). Public on the website, no negotiation.
Pricing not published on Strella's site. Third-party listings report a Starter tier above Diaform's Pro and a Team tier several times higher.
Time to first interview
Minutes from signup. 14-day trial gives you 150 conversations and 2 projects to validate fit before paying.
Days-to-weeks. Sales call, scoping, contracting, then onboarding before you can run a real study end to end.
Per-project knowledge base
Upload product docs, pricing pages, roadmap. The AI references your context to ask informed follow-ups and answer respondent questions accurately mid-conversation.
Strella does not surface a per-project knowledge upload of equivalent depth in its standard product surface.
Built-in panel / recruiting
Bring your own audience: customers, trial users, list, in-app. No built-in panel or recruiting partnerships.
Integrates with recruiting partners like User Interviews.com and Rally to source panel participants without leaving the platform.
Custom moderator personas
One AI interviewer with adjustable probing intensity (1, 3, 5) and a knowledge base per project, but no fully custom personas.
Configurable AI interviewer personas tuned to research style, useful for research teams running varied study formats.
Highlight reels / video clips
Captures voice, transcript, sentiment, themes, and quotes per conversation, but no video highlight reel generation.
Generates video highlight reels and shareable clip artifacts geared toward stakeholder readouts and research presentations.
Best for
SaaS teams that want AI interviews running this week across product, churn, onboarding, and marketing, with respondents who type or talk.
Enterprise UX research orgs with dedicated researchers, panel partners, and budget for premium research infrastructure.
SaaS product, CS, marketing, and founder teams running cross-functional research without a dedicated researcher on staff.
Strella
Enterprise UX research teams with dedicated researchers, formal study cycles, and procurement-driven buying.
Respondents type or speak, switching freely per question. Works in any environment, on any device, no microphone required.
Strella
Voice-only call interface. Respondents speak into a mic; ambient noise can interrupt the AI mid-question. No way to type if they prefer or can't talk right now.
Text mode lets respondents answer in private, useful for compensation, performance, or anything they wouldn't say aloud.
Strella
Voice-first design pushes everyone to speak, which third-party reviews note feels less natural for emotional or sensitive topics.
Works in any browser on phone, tablet, or desktop. Text mode is friction-free for respondents commuting, working, or in shared spaces.
Strella
Browser-based and voice-first. Mobile respondents need a quiet space and a working mic to participate, which limits when and where they can complete the session.
13 topic + 5 sentiment triggers fire actions in flow: alert Slack, capture an email, offer a discount, book a meeting, redirect to a save call.
Strella
Strong synthesis after the fact, but no in-flow AI actions that fire mid-conversation based on what the respondent says.
Detects churn risk or price friction mid-interview and can offer a discount code or schedule a CS save call. Converts at-risk users back.
Strella
Built for research insight, not retention recovery. No native save-offer or discount-trigger workflow inside the interview.
Pro $89/mo ($74/mo annual). Business $149/mo ($124/mo annual). Public on the website, no negotiation.
Strella
Pricing not published on Strella's site. Third-party listings report a Starter tier above Diaform's Pro and a Team tier several times higher.
Minutes from signup. 14-day trial gives you 150 conversations and 2 projects to validate fit before paying.
Strella
Days-to-weeks. Sales call, scoping, contracting, then onboarding before you can run a real study end to end.
Upload product docs, pricing pages, roadmap. The AI references your context to ask informed follow-ups and answer respondent questions accurately mid-conversation.
Strella
Strella does not surface a per-project knowledge upload of equivalent depth in its standard product surface.
Bring your own audience: customers, trial users, list, in-app. No built-in panel or recruiting partnerships.
Strella
Integrates with recruiting partners like User Interviews.com and Rally to source panel participants without leaving the platform.
One AI interviewer with adjustable probing intensity (1, 3, 5) and a knowledge base per project, but no fully custom personas.
Strella
Configurable AI interviewer personas tuned to research style, useful for research teams running varied study formats.
Captures voice, transcript, sentiment, themes, and quotes per conversation, but no video highlight reel generation.
Strella
Generates video highlight reels and shareable clip artifacts geared toward stakeholder readouts and research presentations.
SaaS teams that want AI interviews running this week across product, churn, onboarding, and marketing, with respondents who type or talk.
Strella
Enterprise UX research orgs with dedicated researchers, panel partners, and budget for premium research infrastructure.
Strella is an AI interviewer for enterprise UX research teams. It pairs AI-led sessions with synthesis tools, insights boards, panel partnerships, video highlight reels, and AI-generated reports. The model is sales-led, with demo-required pricing.
Diaform is an AI interviewer for product, CS, marketing, and founder teams at SaaS companies. It runs adaptive follow-ups, voice or text, in 30+ languages, with per-session synthesis (sentiment, themes, quotes) and a per-project knowledge base so the AI can reference your product context mid-conversation. It also runs mid-interview automations: offer a discount when the AI detects price friction, alert Slack on a churn signal, capture a lead when intent spikes, redirect to a meeting when a prospect is ready. Pricing is public, signup is self-serve.
Strella's interface mimics a phone call. Respondents have to speak into a microphone in a quiet space, and ambient noise can interrupt the AI mid-question. No option to type if they prefer or aren't somewhere they can talk.
No public pricing. To get a number, you book a sales call. Procurement-friendly, less so for a PM who wants to try the tool tonight and compare with a budget number in mind.
Insights boards, panel partnerships, and video highlight reels are valuable for a dedicated research org. They're overkill if you're a PM, founder, or CS lead running interviews on the side of your other work.
Each respondent picks text or voice and can switch between them in the same session. No microphone required, no quiet-room requirement, works on the bus, in an office, or on the couch.
13 topic + 5 sentiment triggers fire actions in real time: alert Slack on a churn signal, offer a discount when Diaform hears price friction, book a meeting when intent spikes, capture an email when a lead surfaces.
Upload PDFs and DOCX product docs, pricing pages, roadmap. The AI references your actual product context to ask informed follow-ups and answer respondent questions accurately mid-conversation.
Voice and text in the respondent's own language. Summaries come back in English so the team reads one consistent format.
Pro $89/mo, Business $149/mo, both listed publicly. 14-day trial gives you 150 conversations and 2 projects to validate fit. No sales call between you and a real interview today.
Branded subdomain by default, custom domain on Business. Share via email, Slack, in-app, calendar invite, or QR. Works in any modern browser, no recruiting partners required.
Strella suits dedicated UX research teams running formal study cycles with screeners, panel partnerships, and video highlight reels. It's also the right call when enterprise procurement is involved and the research budget can support premium tooling and a sales cycle.
Diaform fits SaaS teams that want AI interviews running this week, on transparent pricing, with respondents who can type or talk depending on where they are. One tool covers product feedback, churn calls, onboarding, and marketing research, with mid-interview actions that fire in real time when the AI hears a save signal or buying intent.
Yes. Diaform supports both text and voice, and respondents pick which one they want, switching between them inside the same interview. Strella's interface is built around voice conversation, which works in a quiet room with a working microphone but is awkward for respondents on the go, in shared spaces, or those who simply prefer to type.
Not for Diaform. Text mode works anywhere a respondent can read a screen. Voice is optional and never forced. Strella's voice-first call interface relies on a clean audio signal: ambient noise can interrupt the AI mid-question and cut into the conversation flow.
Same category, AI-led interviews, different buyer and different interface model. Strella ships a voice-only experience for enterprise research teams. Diaform ships type-or-talk interviews for SaaS product, CS, marketing, and founder teams, plus mid-interview automations that fire actions in real time.
Both run AI-led interviews with adaptive follow-ups, sentiment, themes, and quotes per session. Diaform additionally supports text input alongside voice, mid-interview automations, and per-project knowledge bases. Strella adds insights boards and panel recruiting partnerships geared specifically to dedicated research teams.
Strella's pricing is not published on their website. Third-party listings report a Starter tier starting above Diaform Pro and a Team tier several times higher. Diaform is upfront: Pro $89/mo ($74/mo annual), Business $149/mo ($124/mo annual), with a 14-day trial.
Strella partners with recruiting platforms like User Interviews.com and Rally. Diaform doesn't recruit for you, you bring your own audience and share one link via email, in-app, Slack, calendar invite, or QR.
Diaform does not use customer conversation data to train AI models.
Dive into the other ways Diaform can power your research.
Stop guessing why users leave. Start an automated interviewer in seconds and get the deep insights of a Zoom call at the scale of a survey.
14-day free trial · No demo required