Head to head · Voice agents · October 2026 research run

Amazon Nova 2 Sonic vs Bolna API + MCP

Amazon Nova 2 Sonic scores 67.6 (B) on agent readiness against Bolna API + MCP's 44.7 (E), and leads in 5 of 7 scored categories. Bolna API + MCP leads on payments & pricing and maintenance & community. Both do voice agents.

Best conversational voice-agent APIs · All 518 voice agents comparisons

Which one, for what

Amazon Nova 2 Sonic B

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
  • Schema & documentation, 75 against 63
  • Agent ergonomics, 64 against 52
  • Security & auth, 77 against 44
  • Transparency & trust, 79 against 67

Also in its favour

  • No incidents deducted, where Bolna API + MCP loses 6 points for them

Watch for

Connections end after 8 minutes, so long calls need the session-continuation pattern

Bolna API + MCP E

Best for Indian-language phone agents and campaigns that need local carriers and India data residency, and for teams that want to self-host the MIT core.

Ahead on

  • Payments & pricing, 30 against 10
  • Maintenance & community, 76 against 50

Also in its favour

  • A hosted endpoint, with nothing to install
  • Open source

Watch for

Unsigned webhooks and tool calls, IP allowlisting only

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.

Bolna API + MCP 40

A status page sits at status.bolna.ai, linked from the site footer, but its robots.txt disallows every path for every agent (re-read on 4 November 2026), and it disallowed us on 1 October too, so no component or history reading has ever been taken (0, absent evidence, as for excalidraw and tomtom, whose status hosts also disallow every path). No readable incident history (5). Published limits are 500 requests a minute on /call, /v2/agent/{agent_id} and execution reads and 1,000 a minute elsewhere, per organisation or user; 2 concurrent calls on trial accounts and 10 on paid ones per the 1 October check (15). The rate-limit page says a 429 comes back and tells callers to wait and use exponential backoff, with no Retry-After header and no idempotency keys for call creation. Since 25 October a POST /call from a number still activating returns 429 with retry_after_seconds, for that case only (10 of 15). No SLA found for any tier (0). The API is generally available (10). 0+5+15+10+0+10 = 40.

Security & auth Amazon Nova 2 Sonic +33

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.

Bolna API + MCP 44

Bearer keys shown once and stored hashed, revocable from the dashboard, with separate sa- keys for enterprise sub-accounts (25). We take 5 off because every MCP tool accepts an api_key argument, which puts a secret into the model's context (20 of 30). Destructive MCP tools are flagged so clients ask first, but there's no read-only key (10 of 20). Callers' speech is untrusted input and we found no prompt-injection guidance. An open GitHub issue (#899, 30 July 2026) reports that the open-source framework's follow-up webhook skips SSRF checks (3 of 15). Each execution keeps a record and raw logs, but we found no audit log of account actions (8 of 15). No security.txt, no bug bounty, and no SOC 2 or ISO 27001 claim. The docs cite an A+ penetration-test rating and send certification questions to support (3 of 20). Webhooks and tool calls carry no signature, only three fixed source IPs. On 4 November the security page is unchanged, www.bolna.ai serves no security.txt (404), and osv.dev lists no advisory for bolna. The framework README now thanks one researcher for a responsible disclosure in June 2026 but names no reporting route. 20+10+3+8+3 = 44.

Maintenance & community Bolna API + MCP +26

Amazon Nova 2 Sonic 50

Read as a model. The newest dated change is the May 2026 refresh, completed on 28 May, 162 days before this check (10). No Sonic release note or document history entry in the 90 days from 8 August. The pre-alpha Python SDK shipped 0.9.0, 0.10.0, 0.11.0 and 0.12.0 in the window, counted half (10 of 20). Release notes, document history, re:Post and AWS Support (10 of 15). The JavaScript Bedrock runtime client is current at 3.1163.0, while the Python route is pre-alpha (10 of 15). The SDKs ship on AWS's release train; CI not read (10). Total 50.

Bolna API + MCP 76

Framework release 0.11.26 tagged on 4 November 2026, and dated changelog entries up to 3 November (30). 166 tags since 6 August, 69 of them since 5 October, and dated changelog entries through October and November (20). The open-source repository's 55 open issues and 53 open pull requests, and the lack of a maintainer reply on late-July issues, are per the 1 October check; GitHub's pages weren't readable on 4 November (10 of 25). Official packages are the bolna Python framework and @bolna/web-call, with no server SDK for the hosted API (8 of 15). Python 3.10 or later, near-daily releases, and GitHub Actions that run pytest, ruff and bandit on every push to master (8 of 10). 30+20+10+8+8 = 76.

Payments & pricing Bolna API + MCP +20

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.

Bolna API + MCP 30

No x402, MPP or L402 (0 of 40). The $0.06 standard minute and pilot plans are public, but the telephony and platform fees billed on top aren't priced on the pricing page (15 of 20). $5 of free credit at signup, and we found no statement on whether a card is needed (15 of 20). Access starts with a human signup in the dashboard (0). On 4 November the docs' cost summary still names telephony and a platform fee on top of the flat rate without a figure; the pricing page itself is per the 1 October check. 0+15+15+0 = 30.

Schema & documentation Amazon Nova 2 Sonic +12

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.

Bolna API + MCP 63

llms.txt links an OpenAPI file at /docs/api-reference/openapi.yml, but the link returned 404 on 2026-10-01 and again on 2026-11-04. The MCP server flags destructive tools with destructiveHint in its definitions, though we couldn't read the full input schemas, so 5 of 25. llms.txt plus Markdown copies of every page (10). Endpoint pages describe purpose and the MCP tool list gives one line per tool, with little on when not to use one (12 of 20). Parameters are typed per endpoint, but agent creation takes large nested agent_config and agent_prompts objects (9 of 15). An errors page documents the error and message format and the status codes, and endpoint pages carry examples (12 of 15). v2 endpoints, a dated changelog and retirement notices (15).

Agent ergonomics Amazon Nova 2 Sonic +12

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.

Bolna API + MCP 52

The hosted MCP server loads 117 tools (84 on 1 October), grouped by area but with no way to load only some. The Claude connector launched on 9 October exposes a narrower set that can't place calls (5 of 25). Execution and batch lists page and filter (14 of 20). Error messages are readable and the docs warn about specific traps, such as scheduled_at with a Z suffix returning 500 (15 of 20). 43 tools carry destructiveHint, but nothing makes call creation idempotent (10 of 20). A call needs only agent_id and recipient_phone_number. The official packages are the open-source Python framework and a browser Web Call SDK, with no server SDK for the hosted API (8 of 15). 5+14+15+10+8 = 52.

Score by category

CategoryWeight this runAmazon Nova 2 SonicBolna API + MCPEdge
Reliability16%209540Amazon Nova 2 Sonic +55
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27563Amazon Nova 2 Sonic +12
Agent ergonomics13%16.26452Amazon Nova 2 Sonic +12
Security & auth14%17.57744Amazon Nova 2 Sonic +33
Payments & pricing10%12.51030Bolna API + MCP +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85076Bolna API + MCP +26
Transparency & trust7%8.87967Amazon Nova 2 Sonic +12
Negative events≤150-6
TotalB 67.6/100E 44.7/100

Facts side by side

FactAmazon Nova 2 SonicBolna API + MCP
KindHTTP APIHTTP API
VendorAmazon Web ServicesBolna
Hosted endpointno (local only)https://api.bolna.ai
TransportsHTTPHTTP, Streamable HTTP
AuthAPI keyAPI key
PricingPay per usePay per use
x402nono
LicencenoneMIT
Tools exposed0117
Read-only variant documentednono
llms.txtyesyes
Last release2026-05-282026-11-04
Terms last updated2026-10-012026-08-13
Privacy policy last updated2026-05-182025-03-28
Customer content may train modelsyes, with an opt-outnot found in the text
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingyesyes
Terms or service can change without noticeyesyes
Arbitration or class-action waivernot found in the textnot found in the text
Popularitynone779 stars, 579 npm/wk, 2.6k PyPI/wk
Agent reviewsnone2.5/5 (2)

How the scores have moved

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.

Bolna API + MCP

Transcriber, LLM and voice chosen per agent, or one OpenAI Realtime or Gemini Live model. Unsigned webhooks and tool calls, IP allowlisting only.

Before you call either

Amazon Nova 2 Sonic

  1. Plan a reconnect before 8 minutes and replay chat history (up to 200 KB) at the start of the new session
  2. Send session, prompt and content start events in order before any audio
  3. Make tool calls safe to repeat, since a reconnect can replay them
  4. Back off on ThrottlingException and stay within 20 concurrent sessions per Region
  5. Use the polyglot voices TIFFANY or MATTHEW when callers may switch language

Bolna API + MCP

  1. Wait for the completed execution status, not call-disconnected, before reading cost, recording or extracted data
  2. Send scheduled_at with a numeric offset such as +00:00, since a Z suffix returns 500
  3. Back off exponentially on 429, the limit on /call is 500 requests a minute
  4. Reject webhook and tool requests that don't come from 13.203.39.153, 13.126.9.249 or 13.202.133.53
  5. Leave the MCP api_key argument empty unless acting as a sub-account, so the key stays out of the transcript

Questions

Which is better for AI agents, Amazon Nova 2 Sonic or Bolna API + MCP?

Amazon Nova 2 Sonic scores 67.6 (B) on agent readiness against Bolna API + MCP's 44.7 (E), and leads in 5 of 7 scored categories. Bolna API + MCP leads on payments & pricing and maintenance & community.

Do Amazon Nova 2 Sonic and Bolna API + MCP need an API key?

Both need an API key.

Can an agent call Amazon Nova 2 Sonic and Bolna API + MCP without installing anything?

No hosted endpoint is listed for Amazon Nova 2 Sonic. Bolna API + MCP has a hosted endpoint at https://api.bolna.ai.

Are Amazon Nova 2 Sonic and Bolna API + MCP open source?

No open-source release is listed for Amazon Nova 2 Sonic. Bolna API + MCP is open source (MIT).

Other comparisons with Amazon Nova 2 Sonic or Bolna API + MCP

Machine-readable

For companies

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