Head to head · Voice agents · October 2026 research run
Amazon Nova 2 Sonic vs Vocily AI
Amazon Nova 2 Sonic scores 67.6 (B) on agent readiness against Vocily AI's 53.9 (D), and leads in 3 of 7 scored categories. Vocily AI leads on schema & documentation, agent ergonomics, payments & pricing and maintenance & community. Both do voice agents.
Best conversational voice-agent APIs · All 518 voice agents comparisons
Which one, for what
Best for Voice agents on AWS, call centres on Amazon Connect, teams that want IAM and in-account data handling.
Ahead on
- Reliability, 95 against 40
- Security & auth, 77 against 46
- Transparency & trust, 79 against 48
Also in its favour
- No incidents deducted, where Vocily AI loses 5 points for them
Watch for
Connections end after 8 minutes, so long calls need the session-continuation pattern
Best for Indian-language phone agents where a backend builds agents, places outbound calls and reads results over REST, with prepaid rupee billing.
Ahead on
- Schema & documentation, 90 against 75
- Agent ergonomics, 84 against 64
- Payments & pricing, 40 against 10
- Maintenance & community, 61 against 50
Also in its favour
- A hosted endpoint, with nothing to install
Watch for
No status page, incident history or SLA was found
Why the edge
Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.
Reliability Amazon Nova 2 Sonic +55
Amazon Nova 2 Sonic 95
Hosted reading. AWS Health Dashboard with per-service, per-Region history (20). The dashboard history file (newest event 30 October 2026) lists no Bedrock event in the 90 days from 8 August, and the 3 September us-west-2 event names STS, Connect and IAM Identity Center, not Bedrock. The public dashboard records broad events only, so 25 of 30, as amazon-nova-embeddings was read. Quotas published, 20 concurrent requests per Region, not adjustable (15). The stream API lists ThrottlingException (429), ServiceUnavailableException (503), ModelTimeoutException (408) and ModelStreamErrorException (424), Bedrock's troubleshooting guide advises backoff with jitter, and the 8-minute connection limit comes with a session-continuation sample (15). Bedrock's SLA of 99.9 per cent a month per Region for model APIs, as read for amazon-nova-embeddings on 1 November (10). Generally available since 2 December 2025 (10). 20 + 25 + 15 + 15 + 10 + 10 = 95.
Vocily AI 40
Graded on the public REST API at api.vocily.ai, read as a hosted service. No status page found: status.vocily.ai gave no answer on 4 November and neither the site nor the docs link one (0). No readable incident history (5). The limit is published as 300 requests a minute per key (moving window), with ten concurrent calls per organisation included (15). A 429 carries Retry-After and X-RateLimit headers, and POST /v1/calls, the write that places a billed call, requires an Idempotency-Key and returns the original call on a retry (15). No SLA found. The terms say availability isn't guaranteed (0). The docs don't label the API beta, but nine dated changes from 23 September to 30 October 2026 changed the /v1 contract, seven of them with removals, changed error codes or changed meanings, and the terms still allow for beta and pre-launch service; the 8 October reading of the API root's version is struck (a request to the product's own endpoint), and the partial is carried (5 of 10). 0 + 5 + 15 + 15 + 0 + 5 = 40.
Security & auth Amazon Nova 2 Sonic +31
Amazon Nova 2 Sonic 77
SigV4 with IAM roles and temporary credentials scoped per model ARN, as the Sonic quickstart signs (30). Tools run in the client, so side effects are the developer's to approve, and IAM can restrict which models a role invokes, with no approval step in the API (12 of 20). The model listens to callers and acts on tool results, and no prompt-injection guidance was found in the Sonic guide (5 of 15). CloudTrail logs Bedrock API calls, read as amazon-nova-embeddings was (12 of 15). VDP on HackerOne, Bedrock in SOC scope and a valid security.txt on aws.amazon.com, with no paid bounty, as on the other AWS listings (18 of 20). Total 77.
Vocily AI 46
Bearer keys are shown once, revocable in the dashboard and bound to one workspace, and they can't reach billing, members or key management. There are no scopes to set and no rotation route, and webhooks are HMAC-signed with a timestamp and a rotation overlap (22 of 30). No read-only key. Spending and contractual actions stay in the dashboard, a version answers calls only after publish and make-live, and the memory erase previews by default (10 of 20). Transcripts and caller speech are untrusted content, and the API docs have no prompt-injection guidance. The site describes topic fencing and an empty-knowledge-base guard (4 of 15). Each call keeps a record with cost and version, webhooks have a delivery log and every response a request id, but we found no audit log of account or key actions (8 of 15). No security.txt (404 on 4 November), disclosure policy, bug bounty or certification. The compliance page says Vocily doesn't claim certification, and the privacy policy states encryption in transit and at rest (2 of 20). 22 + 10 + 4 + 8 + 2 = 46.
Transparency & trust Amazon Nova 2 Sonic +31
Amazon Nova 2 Sonic 79
Closed model under the AWS Service Terms, with Apache-2.0 SDKs and samples (15). Bedrock stores no inputs or outputs by default and model providers can't see them, Sonic isn't on the abuse-detection page's list of models whose traffic is stored, and section 50.3 doesn't list Bedrock among services whose content improves AWS services, as read for amazon-nova-embeddings on 1 November (22 of 30). Bedrock's lifecycle policy for models launched before 7 September 2026 promises 12 months and a Legacy period of at least 6 months, but the March and May refreshes changed the model in place under the same ID (15 of 20). Regions are listed, with sub-processors not read (12 of 20). Total 64.
Vocily AI 48
A closed service. The terms (10 June 2026) name no legal entity or governing law, still describe a possible beta, and say paid plans may come later while prices are live (10 of 30). The privacy policy (3 September 2026) is written mainly around WhatsApp data and gives no retention period. The compliance page says recordings are kept for the life of the account and deleted on request, and audio and transcript storage are per-agent settings. No DPA found (12 of 30). The reference promises additive changes within /v1, but removals shipped on 23 and 25 September and 10 and 30 October 2026 with same-day notes and migration tables and no notice period (6 of 20). The privacy policy mentions vetted providers without naming them. The compliance page now says call records, transcripts and recordings are stored on AWS in Mumbai (ap-south-1), that model providers process in their own regions and that Plivo carries calls; no sub-processor list was found, so the partial is carried (6 of 20). 10 + 12 + 6 + 6 = 34.
Payments & pricing Vocily AI +30
Amazon Nova 2 Sonic 10
No x402, MPP or L402 (0). The Nova and Bedrock pricing pages carry a speech-to-speech table drawn by script, so the per-token prices weren't read and this line scores absent, which is our reader's limit and not the vendor's (0). New accounts get up to $200 in Free Tier credits, and the Free Tier FAQ says most new customers need no payment method, read as half on the other AWS listings (10). A person signs up for an AWS account in a browser (0). Total 10.
Vocily AI 40
No x402, MPP or L402 (0 of 40). Per-minute and per-reply prices are public without a login in rupees and US dollars, voice from 4.10 cents a minute and chat from 0.10 cents a model reply, with a 3.00 cents a minute platform fee and capacity packs at $8 a month (20). A new organisation gets 200 credits (₹200) or 2 credits ($2) once its owner's email is verified, and the pricing page says no card (20). Access starts with a browser signup and email verification, and API keys can only be created in the dashboard (0). 0 + 20 + 20 + 0 = 40.
Agent ergonomics Vocily AI +20
Amazon Nova 2 Sonic 64
Scored as an API. Responses carry transcripts of both sides and usage events, chat history is capped at 200 KB and can be injected once per session (15 of 25). Output controls are voice, turn-taking sensitivity and text or audio input (12 of 20). Typed exceptions with HTTP codes, while errors inside the event stream are less documented (15 of 20). Asynchronous tool calls let the model keep talking, and AWS samples show how to resume after the 8-minute limit, with nothing on repeating tool side effects after a reconnect (12 of 20). A session needs a sequence of start events before audio. The JavaScript SDK is current, but the Python SDK the quickstart uses is pre-alpha and needs Python 3.12 (10 of 15). Total 64.
Vocily AI 84
List calls take limit from 1 to 100, default 20, and return the transcript only with include=transcript (20 of 25). Every growing list uses the same cursor envelope, and calls filter by agent, status, direction, origin and date. The bounded lists return bare arrays (18 of 20). Errors carry a machine-readable detail.code, a field path on validation failures and an X-Request-ID (20). Idempotency-Key is required on call creation, agent edits accept If-Match on a document revision, and the bulk memory erase previews unless dry_run is false. Other writes have no idempotency key (18 of 20). A call needs only agent_id and to_number and an agent only name. No SDK was found in the docs, on npm or on PyPI (8 of 15). 20 + 18 + 20 + 18 + 8 = 84.
Schema & documentation Vocily AI +15
Amazon Nova 2 Sonic 75
The Bedrock service model types InvokeModelWithBidirectionalStream, but the Sonic events inside it (session, prompt, content, tool and usage events) are JSON payloads documented only in the guide, with no schema file (12 of 25). llms.txt and Markdown copies of the Nova 2 guide (10). Guides on the event lifecycle, barge-in, turn-taking, async tools and chat history say when and how to use each (16 of 20). Event fields are documented as JSON examples and tables, not typed schemas (10 of 15). Sample repositories in several languages and the API's exceptions with HTTP codes (12 of 15). Release notes and document history, with in-place model refreshes and a versioned model ID (15). Total 75.
Vocily AI 90
A public OpenAPI 3.1 file, linked from llms.txt, with 60 operations on 4 November (54 on 8 October) at docs.vocily.ai/developers/openapi.json (25). llms.txt, llms-full.txt and a Markdown copy of every page (10). Pages say what each route is for and what to use instead, such as webhooks over polling and dashboard batches over a loop of calls, though some operation titles are generated names such as Create Kb (16 of 20). Bodies refuse unknown fields and carry ranges and enums, but list filters such as status are plain strings and variables and metadata are free-form (12 of 15). 234 example entries in the spec, a reason-code table by status and a 422 that lists every invalid field (15). The /v1 prefix and a dated API changes page from 23 September 2026, which records removals made under /v1 (23 and 25 September, 10 and 30 October) against the reference's own rule that fields are never removed within a version (12 of 15). 25 + 10 + 16 + 12 + 15 + 12 = 90.
Score by category
| Category | Weight this run | Amazon Nova 2 Sonic | Vocily AI | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 95 | 40 | Amazon Nova 2 Sonic +55 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 75 | 90 | Vocily AI +15 |
| Agent ergonomics | 13%16.2 | 64 | 84 | Vocily AI +20 |
| Security & auth | 14%17.5 | 77 | 46 | Amazon Nova 2 Sonic +31 |
| Payments & pricing | 10%12.5 | 10 | 40 | Vocily AI +30 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 50 | 61 | Vocily AI +11 |
| Transparency & trust | 7%8.8 | 79 | 48 | Amazon Nova 2 Sonic +31 |
| Negative events | ≤15 | 0 | -5 | |
| Total | B 67.6/100 | D 53.9/100 |
Facts side by side
| Fact | Amazon Nova 2 Sonic | Vocily AI |
|---|---|---|
| Kind | HTTP API | HTTP API |
| Vendor | Amazon Web Services | Vocily AI Private Limited |
| Hosted endpoint | no (local only) | https://api.vocily.ai |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | none | Proprietary service under Vocily's terms of service. No open-source code or published package was found |
| Tools exposed | 0 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-05-28 | 2026-10-30 |
| Terms last updated | 2026-10-01 | 2026-06-10 |
| Privacy policy last updated | 2026-05-18 | 2026-09-03 |
| Customer content may train models | yes, with an opt-out | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
How the scores have moved
Amazon Nova 2 Sonic
No score change since it was listed.
Verdicts
Amazon Nova 2 Sonic
Nova 2 Sonic runs speech-to-speech conversations with asynchronous tools on Bedrock, with IAM scoping, no default storage of inputs and a 99.9 per cent SLA. Sessions cut off at 8 minutes, the Python SDK is pre-alpha, and the event payloads have no schema file. Prices are in a script-drawn table we couldn't read.
Vocily AI
The REST API is documented in detail, with an OpenAPI 3.1 file of 60 operations, a required idempotency key on calls, Retry-After on 429 and signed webhooks. No status page, SLA, SDK or security programme was found, and releases from September to 30 October 2026 removed fields under /v1 on the day they were announced.
Before you call either
Amazon Nova 2 Sonic
- Plan a reconnect before 8 minutes and replay chat history (up to 200 KB) at the start of the new session
- Send session, prompt and content start events in order before any audio
- Make tool calls safe to repeat, since a reconnect can replay them
- Back off on
ThrottlingExceptionand stay within 20 concurrent sessions per Region - Use the polyglot voices TIFFANY or MATTHEW when callers may switch language
Vocily AI
- Send a fresh UUID in
Idempotency-Keyon everyPOST /v1/calls. The API refuses the request without it - Pass a
from_numberthe workspace holds. The shared Test Number returns 403 from the API - Publish a version and make it live before placing a call, or the call returns 409
agent_not_published - Branch on
detail.code, falling back to the top-levelcode. A 429 body is flat, so readRetry-After - Read
currencyon every call and chat record. Costs are in rupees or dollars depending on the organisation
Questions
Which is better for AI agents, Amazon Nova 2 Sonic or Vocily AI?
Amazon Nova 2 Sonic scores 67.6 (B) on agent readiness against Vocily AI's 53.9 (D), and leads in 3 of 7 scored categories. Vocily AI leads on schema & documentation, agent ergonomics, payments & pricing and maintenance & community.
Do Amazon Nova 2 Sonic and Vocily AI need an API key?
Both need an API key.
Can an agent call Amazon Nova 2 Sonic and Vocily AI without installing anything?
No hosted endpoint is listed for Amazon Nova 2 Sonic. Vocily AI has a hosted endpoint at https://api.vocily.ai.
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Machine-readable
- This page as Markdown
/compare/amazon-nova-sonic-vs-vocily.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/amazon-nova-sonic.json·/api/v1/tools/vocily.json - From a terminal
anchor compare amazon-nova-sonic vocily(the CLI) - Over MCP
compare_tools {"a": "amazon-nova-sonic", "b": "vocily"}at/mcp, no key