Iii vs Presto Voice

Side-by-side comparison of features, pricing, and ratings

Analysis reviewed Live tool data as of 2026-10-18
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At a glance

DimensionIiiPresto Voice
PricingFree (open-source)Contact for pricing (custom enterprise)
Best ForBackend engineers and agent buildersQSR chains with drive-thrus
Core TechnologyDistributed services runtime with workers/triggers/functionsVoice AI automation for drive-thrus
Integration CapabilityPolyglot workers (Node, Rust, Python, Go), any runtimePOS and headset systems, ElevenLabs
DeploymentSelf-hosted: Docker, Kubernetes, edge, browser, RPiOn-site at restaurant locations
Latest News2026-06-01: v0.20.0 SDK reorganization; cross-language API alignment2026-04-16: Dairy Queen partnership for drive-thru AI
Try IiiTry Presto Voice
Iii
Iii

iii is an open-source distributed runtime that runs every function, service, and AI agent as a worker over one shared protocol.

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Presto Voice
Presto Voice

Presto Voice is drive-thru voice AI that takes QSR orders and upsells every car at the speaker post.

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Pricing
Free
Contact Sales
Plans
$0/mo
—
Popularity
9 views
7.5k views
Skill Level
Intermediate
Intermediate
API Available
Platforms
CLI
API
Categories
⚙️ Developer Infrastructure
🍽️ Restaurant & Hospitality☎️ Voice AI Agents & Phone Automation
Features
Three primitives: Function, Trigger, and Worker
Worker registry with one-command capability install via compose::add
Workers declared in a Compose file and immediately callable system-wide
Polyglot SDKs for TypeScript, Python, and Rust
Cross-language function calls over a shared WebSocket protocol (ws://localhost:49134)
Engine handles serialization and routing between workers
Durable state, retries, and dead-letter handling built into the engine
compose::update resolves selected workers and shared dependencies as one graph (0.24.5+)
Unified console showing live logs, traces, streams, and state
Trace query pagination via root-span keys, 2098ms to 35ms on a 50-trace query (0.24.4)
Spans accept include_events: false for leaner trace responses (0.24.4)
Static musl build installs glibc-only Linux workers on Alpine-adjacent hosts (0.24.5+)
Agents run as workers — functions as tools, state as session memory, triggers as orchestration
Agents can register new workers at runtime and expose new functions
Self-hosted on a laptop, your own cloud, or your hardware with the same worker contract
Automated drive-thru order taking via voice AI at the speaker post
Continuous upselling of add-ons and specials to raise average order value
Runs a spectrum of Voice AI approaches rather than a single model
Vendor-published up to 95% non-intervention rate on drive-thru orders
Vendor-published up to 88% upsell offer rate
Vendor-published up to 6% monthly incremental revenue increase
24/7 drive-thru ordering availability
Installation at scale without disrupting live drive-thru lanes
POS and headset provider integration handled by Presto
Available through the Toast Partner Ecosystem (Sept. 21, 2026)
Managed deployment with ongoing vendor support
ROI reporting across non-intervention, upsell, and revenue lift
Nationwide rollout experience at Wienerschnitzel, Taco John's, and Dairy Queen
15+ years of restaurant drive-thru automation experience since 2008
$10M raise (Sept. 28, 2026) funding Voice AI deployments
Integrations
Toast

What real users say: Iii vs Presto Voice

Not marketing copy and not our opinion — a structured sweep of public discussion (reviews, forums, communities and video comments), showing what people praise and what they complain about for each tool.

Iii

63 mentions across 4 sources · mixed

Reddit, Hacker News, App Store, Lemmy

What users praise

  • • Open-source and free to use, reducing financial risk.
  • • Unified three-primitives model simplifies complex service composition.
  • • Polyglot support for Node.js, Rust, Python, Go, and more.
  • • One-command worker installation mirrors npm package simplicity.

What frustrates them

  • • No community feedback to confirm any feature works as advertised.
  • • Zero adoption signals — may be vaporware or unmaintained.
  • • Version 0.20.x indicates alpha-stage instability.
  • • No paid support tiers for enterprise reliability needs.

Researched Jul 3, 2026

Presto Voice

37 mentions across 3 sources · 32% positive — critical (weighted across 3 sources)

YouTube, App Store, Lemmy

What users praise

  • • Handles POS and headset integration itself, so voice AI goes live in an active lane without pausing service
  • • Built specifically for multi-location QSR franchise groups, not single shops or dine-in concepts
  • • Continuous upselling of add-ons and specials on every transaction targets average-order-value lift
  • • 24/7 drive-thru ordering availability removes the labor constraint of shift coverage at the speaker post

What frustrates them

  • • Almost no independent, on-topic community reviews — the dataset is dominated by unrelated same-name products
  • • Vendor-published KPIs (95% non-intervention, 88% upsell, 6% lift) lack third-party verification
  • • Won't hand over the model to tune, which blocks teams that want to own and iterate on the voice stack
  • • Only Toast is documented as a named POS integration in the available data

Researched Oct 14, 2026

Who should pick which

  • QSR chain operations director
    Pick: Presto Voice

    Presto Voice automates drive-thru ordering with high accuracy and upselling, directly boosting revenue and staff efficiency. Recent partnership with Dairy Queen validates its scalability.

  • Backend engineer building agent harness
    Pick: Iii

    iii provides a unified runtime with workers, triggers, and functions, and its agent-first approach (as per May 2026 news) makes it perfect for building custom agent systems. Free and self-hosted.

  • Solo developer of distributed app
    Pick: Iii

    With iii, you can compose services using three primitives, deploy anywhere, and get built-in state and queues. No cost, and the cross-language calls (Node, Rust, Python, Go) reduce overhead.

  • Franchise owner with 5 drive-thru locations
    Pick: Presto Voice

    Presto Voice's easy installation at scale, upselling engine, and measurable ROI (up to 6% revenue lift) are tailored for multi-location QSR operators.

  • Platform team shipping internal capabilities
    Pick: Iii

    iii's worker registry (`iii worker add`) and polyglot support allow platform teams to ship capabilities as workers, with unified observability. The self-hosted nature avoids vendor lock-in.

Frequently Asked Questions

What drives Presto Voice's pricing?

Presto Voice uses contact-based pricing, likely based on number of locations, transaction volume, or subscription. Specifics are not publicly disclosed.

Is iii completely free?

Yes, iii is open-source and free. You only pay for your own infrastructure (cloud, servers, etc.).

Can Presto Voice integrate with my existing POS?

Yes, Presto Voice integrates with major POS and headset systems. It also supports ElevenLabs for voice models.

Which languages can I write workers in for iii?

iii supports workers in Node.js, Rust, Python, and Go, with cross-language function calls.

Does Presto Voice work for non-drive-thru restaurants?

Presto Voice is designed primarily for drive-thru automation. It also includes phone ordering, but is not built for dine-in or delivery-only operations.

Can iii run on a Raspberry Pi?

Yes, iii supports deployment on Raspberry Pi, as well as Docker, Kubernetes, edge, browser, and microVM.

What's the latest on Presto Voice?

In April 2026, Dairy Queen partnered with Presto to deploy Voice AI for drive-thru ordering.

What's new in iii as of June 2026?

iii v0.20.0 (June 1, 2026) includes major SDK reorganization and shared types extraction for Node, Python, and Rust, aligning cross-language APIs.

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Explore each tool further

Iii
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Last reviewed: July 3, 2026