Head to head · Voice agents · October 2026 research run

Deepgram Voice Agent API vs Vaani Developer Platform

Deepgram Voice Agent API scores 72.2 (BB) on agent readiness against Vaani Developer Platform's 44.6 (E), and leads in every scored category. Both do voice agents.

Best conversational voice-agent APIs · All 447 voice agents comparisons

Which one, for what

Deepgram Voice Agent API BB

Best for Developers who already run telephony (Twilio, Amazon Connect, Genesys, AudioCodes) and want a cheap managed pipeline with their choice of LLM.

Ahead on

  • Reliability, 75 against 28
  • Schema & documentation, 90 against 57
  • Security & auth, 71 against 44
  • Payments & pricing, 40 against 22
  • Maintenance & community, 85 against 59
  • Transparency & trust, 78 against 42

Also in its favour

  • Agent-ready, a grade of BB or better
  • Free to start without a card

Watch for

No phone numbers or SIP, so you bridge Twilio or another carrier yourself

Vaani Developer Platform E

Best for Outbound and inbound phone agents and campaigns for Indian businesses, with Hindi, Hinglish and Indian carriers, India DND checks and TRAI calling windows built in, plus WebRTC sessions for apps.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

API keys reach the whole workspace, with no scoped, read-only or per-agent keys

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 Deepgram Voice Agent API +47

Deepgram Voice Agent API 75

Statuspage at status.deepgram.com with component history, a Voice Agent API component and an RSS feed (20). Nineteen incidents in the 90 days from 3 August, and every one is partial by its own text (one datacenter, one region or endpoint, one model or some requests), read as this run reads partial incidents and as deepgram-stt and deepgram-tts are read on the same page. The only one that names the Voice Agent API is 29 October, when authentication at one US datacenter failed some API requests and Voice Agent sessions with 5xx errors from 15:17 to 15:45 UTC. The STT and TTS incidents the pipeline sits on include Flux TTS errors on the global endpoint only from 09:45 to 13:44 UTC on 25 September, some batch STT requests slow or timing out from 19:27 to 21:53 UTC on 22 October and 5xx errors on some requests at one datacenter from 16:00 to 17:09 UTC on 22 October. The 7 July Flux errors and the 21 July Gemini routing failure, read on 1 October with others as several majors, have left the window (cause time). Minor only (20). Concurrency is published, 45 sockets on pay as you go, 60 on Growth in North America and from 100 on Enterprise (15). Over-limit requests get a 429 and the docs recommend exponential backoff, with no Retry-After header and no idempotency guidance for function calls (10 of 15). The pricing page no longer names an uptime level, and we found no SLA terms (0). The Voice Agent API is generally available (10). 20 + 20 + 15 + 10 + 0 + 10 = 75.

Vaani Developer Platform 28

Graded on the hosted REST API at api.vaanivoice.ai. No status page. status.vaani.dev and status.vaanivoice.ai don't resolve, and neither the site nor the docs link one (0). With no history to read, 5. No request rate limits are published. The docs give 2 concurrent calls on pay as you go and a per-organisation campaign concurrency cap, so partial credit (5). The SDK raises RateLimitError on 429 and the MCP client retries once after 600 ms, but no Retry-After, backoff guidance or idempotency key for call creation is documented (3). The pricing table lists a 99.50 per cent uptime SLA on both plans, but no SLA document or service credits were found and the terms supply the service "as-is" with no warranties, so half (5). The API is version 2.0.0 and isn't labelled beta (10). 0+5+5+3+5+10 = 28.

Transparency & trust Deepgram Voice Agent API +36

Deepgram Voice Agent API 78

The service is closed with clear terms, and the official SDKs are MIT (15 of 30, read as deepgram-stt and deepgram-tts are). The docs say audio and transcripts are kept for model improvement unless mip_opt_out is set and describe EU, Australian and Indian endpoints, while the privacy policy (last updated 26 October 2021, re-read on 1 November 2026) says data is stored on US servers and doesn't mention the Model Improvement Program, so the statements disagree (15 of 30). The changelog dates changes and corrections, but we didn't find a published deprecation policy for the agent API (10 of 20). A subprocessor page and EU, India and Australia endpoints are published (20). 15 + 15 + 10 + 20 = 60. The 1 October check gave the licence line 18 and the data-handling line 22, where Deepgram's other listings read the same pages as 15 and 15.

Vaani Developer Platform 42

A closed service. The terms name Vaani AI Research Private Limited, its Bengaluru address, CIN, Indian law and Bengaluru courts, but they're undated, written for the website www.vaaniresearch.com, and say nothing on billing, refunds, API use or customer data. The SDK and MCP server are MIT, with the SDK's full source in its PyPI sdist (14 of 30). The privacy policy (undated) keeps data, including voice recordings, for up to 24 months, while the pricing table gives 30 days' retention on pay as you go and zero retention on Enterprise. Voice data trains models only with explicit consent. No DPA found (8 of 30). No deprecation policy. The privacy policy promises 15 days' notice of significant changes, and the terms allow changes and termination without notice (2 of 20). The privacy policy names vendor categories (cloud hosting, analytics, voice transcription) and says data may be stored outside India. Model and telephony providers can be read from the calculator, and India data residency is offered on demand. No subprocessor list or data location for the hosted service (5 of 20). 14+8+2+5 = 29.

Schema & documentation Deepgram Voice Agent API +33

Deepgram Voice Agent API 90

Public OpenAPI and an AsyncAPI file that describes the agent socket messages (25). llms.txt with a Markdown copy of each page, and a keyless docs MCP server (10). Every client message and server event has its own page saying what it's for, from Settings to ForceEndTurn and FunctionCallRequest (17 of 20). The AsyncAPI types the Settings message with enums and required fields, though provider endpoint.headers are free-form (13 of 15). Examples in every language guide and a Voice Agent errors and warnings page, which we read only in outline (11 of 15). A dated changelog that also publishes corrections, such as the token TTL field name on 18 September 2026 (14 of 15).

Vaani Developer Platform 57

A public OpenAPI 3.1 file at docs.vaani.dev/api-reference/openapi.json, version 2.0.0, but it holds 5 of the 24 operations in the API reference (trigger-call, call history, transcript, stream, call details). It declares the key only as a header parameter with no security scheme, its trigger-call schema leaves out medium and modify_agent, and four response schemas are empty. The MCP tools have typed zod inputs (8 of 25). llms.txt, llms-full.txt and a Markdown copy of each page on Mintlify (10). Pages explain what each route is for and warn where it matters, such as dispatch acceptance not meaning a completed call, transcripts returning 404 while processing, and real paid calls from trigger_call (14 of 20). Ranges and enums are documented (medium, voice_speed 0.6 to 1.4, page_size up to 200, campaign retries 1 to 10, campaign status), but metadata, modify_agent and three MCP tool payloads are free-form objects (9 of 15). Request examples in cURL, Python and JavaScript on every endpoint, a campaign error-code table, 422 and 404 bodies and an SDK exception table by status. No single error reference for the whole API (12 of 15). The docs state API version 2.0.0, but no changelog or release notes page was found (4 of 15). 8+10+14+9+12+4 = 57.

Security & auth Deepgram Voice Agent API +27

Deepgram Voice Agent API 71

API keys carry an owner, admin or member role, can be set to expire, can be created through the API and can be tagged, and browsers get 30-second JWTs from the token endpoint (30). Member keys limit what a leaked key can do, and the function-call hold keeps the agent from firing irreversible tools on a speculative turn, but there's no read-only agent mode (14 of 20). The agent feeds caller speech to an LLM and we found no prompt-injection guidance (5 of 15). Requests are tagged per key and each session reports latency and history, but we found no audit log of account actions (10 of 15). The compliance page states SOC 2 Type 1 and Type 2, HIPAA and PCI. deepgram.com now serves a valid security.txt (Contact security@deepgram.com, Expires 30 September 2027), not found on 30 September. No disclosure policy, bug bounty or public advisories found (12 of 20, the same reading as deepgram-stt and deepgram-tts). 30 + 14 + 5 + 10 + 12 = 71.

Vaani Developer Platform 44

Plain revocable API keys, shown once, several active at a time and rotated by creating a new key and deleting the old one. Every key reaches the whole workspace, with no scoped, read-only or per-agent keys (20). Campaign webhooks are signed with HMAC-SHA256 over a timestamp and the body, with a five-minute replay window in the example (+2). The live-captions URL carries a call-bound token in the query string for 24 hours by default, the documented way for browsers to connect, so 3 off as a judgement call, less than the full 10 because it isn't the account key (19 of 30). The MCP server has a read-only mode and destructive annotations, and its docs, tool descriptions and bundled prompt say to confirm the number and agent with the user before a call. The API itself has no read-only key and nothing stops a call without confirmation (12 of 20). The tool returns transcripts, summaries and entities drawn from callers' speech. No guidance on treating them as untrusted data was found. Agent guardrails exist for the voice agent's own replies (3 of 15). Each call keeps a record in call history and call details, and keys are labelled so calls can be traced to a key, but no account or key audit log is documented (7 of 15). No security.txt (404 on both domains), disclosure policy, bug bounty or certification. vaaniresearch.com marks its security standards "In Progress", the pricing page lists HIPAA compliance on Enterprise with no report or BAA found, and the privacy policy promises breach notice in line with applicable law (3 of 20). 19+12+3+7+3 = 44.

Maintenance & community Deepgram Voice Agent API +26

Deepgram Voice Agent API 85

Changelog entries to 27 October 2026 and the Python and JavaScript SDKs released on 28 October (Python 7.16.0, JavaScript 5.17.0), both adding Voice Agent Think Live messages (30). 34 dated changelog entries in the 90 days from 3 August, several on the Voice Agent API, and eight Python SDK tags from 7.9.0 on 14 September to 7.16.0 on 28 October (20). A public changelog that issues corrections, such as the 8 October correction of the over-limit Configure behaviour, plus support channels we didn't test (12 of 15 for a closed service). Official SDKs current in Python, JavaScript, Java, Go, .NET and Rust, with Voice Agent support for custom Think-provider messages from 8 October (15). MIT SDKs with current releases (8 of 10). 30 + 20 + 12 + 15 + 8 = 85.

Vaani Developer Platform 59

vaani-research-mcp 0.1.1 on 2026-10-14 (30). In the last 90 days, vaani-sdk 0.3.1 on 28 September and three npm versions (0.0.0-stage, 0.1.0, 0.1.1) within 40 minutes on 14 October. No dated changelog, so half (10 of 20). A closed service with no public changelog, issue tracker or community channel found. Contact is hello@vaaniresearch.com and a booking link, and we didn't test whether they answer. The MCP repository on GitHub couldn't be read from this session (4 of 15, the closed-service reading). A current official Python SDK, released seven times since April 2026. The MCP server isn't in the official MCP registry (10 of 15). The SDK's sdist ships its tests and current httpx and pydantic dependencies, and the MCP package runs its tests before publishing, but no public CI was found and the SDK has no repository (5 of 10). 30+10+4+10+5 = 59.

Payments & pricing Deepgram Voice Agent API +18

Deepgram Voice Agent API 40

No x402, MPP or L402 (0 of 40). Per-minute prices for every tier on the public pricing page (20). $200 of credit with no card (20). The first key has to come from a human signup in the Console, though later keys can be made through the API (0).

Vaani Developer Platform 22

No x402, MPP or L402 (0 of 40). The ₹1 ($0.02) a minute platform fee, number rental, concurrency lines and add-ons are public, and the calculator shows each provider's unit rate without a login. Registry checks, extraction and evaluations "can add separate charges" that aren't priced, and the billing pulse depends on the account, so 3 off (17 of 20). The home page says "Start free on Vaani's Platform", but the pricing page states a prepaid wallet with no free credit, trial minutes or card rule, and we didn't sign up to check, so 5 of 20. A person signs up with email verification at platform.vaani.dev and creates keys in the dashboard (0). 0+17+5+0 = 22.

Score by category

CategoryWeight this runDeepgram Voice Agent APIVaani Developer PlatformEdge
Reliability16%207528Deepgram Voice Agent API +47
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29057Deepgram Voice Agent API +33
Agent ergonomics13%16.26764Deepgram Voice Agent API +3
Security & auth14%17.57144Deepgram Voice Agent API +27
Payments & pricing10%12.54022Deepgram Voice Agent API +18
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88559Deepgram Voice Agent API +26
Transparency & trust7%8.87842Deepgram Voice Agent API +36
Negative events≤1500
TotalBB 72.2/100E 44.6/100

Facts side by side

FactDeepgram Voice Agent APIVaani Developer Platform
KindHTTP APIHTTP API
VendorDeepgramVaani AI Research Private Limited
Hosted endpointhttps://agent.deepgram.com/v1/agenthttps://api.vaanivoice.ai
TransportsHTTP, Streamable HTTP, stdio, SSE (legacy)HTTP, stdio
AuthAPI keyAPI key
PricingPay per usePay per use
x402nono
LicenceMIT (SDKs)Proprietary hosted service under Vaani AI Research's terms of service. The Python SDK (vaani-sdk) and the local MCP server (vaani-research-mcp) are MIT. The SDK's full source ships in its PyPI sdist, and the MCP server's npm package holds only the bundled JavaScript
Tools exposednone9
Read-only variant documentednoyes
llms.txtyesyes
Last release2026-10-282026-10-14
Terms last updated2026-08-06no date given
Privacy policy last updated2021-10-26no date given
Customer content may train modelsyes, with an opt-outnot found in the text
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticeyesyes
Arbitration or class-action waiveryesnot found in the text
Popularity468 stars, 1.1M npm/wk, 805k PyPI/wk14 npm/wk, 19 PyPI/wk
Agent reviews3/5 (2)none

How the scores have moved

Verdicts

Deepgram Voice Agent API

$0.075 a minute all in on Standard, $0.050 with your own LLM and TTS, and $200 of credit with no card. Every status incident since August was partial. No phone numbers or SIP, so you bridge Twilio or another carrier yourself, and call audio is kept for model improvement unless each session opts out.

Vaani Developer Platform

Docs are detailed and served as llms.txt, campaign webhooks are signed, and the MCP server ships a read-only mode with tool annotations. Keys reach the whole workspace, the OpenAPI file covers 5 of 24 documented operations, there's no status page, changelog or idempotency key, and the privacy policy and pricing page disagree on retention.

Before you call either

Deepgram Voice Agent API

  1. Set mip_opt_out in the Settings message to keep call audio out of training
  2. Use the function-call hold for anything irreversible, since replies can start before the user's turn is confirmed
  3. Back off exponentially on 429, a pay-as-you-go project gets 45 concurrent sockets
  4. Pin the LLM version, an unpinned Gemini route failed for 1.5 hours on 21 July 2026
  5. Mint browser tokens with ttl_seconds, not ttl, or they expire after 30 seconds

Vaani Developer Platform

  1. Send the key as X-API-Key, not Authorization. A missing or wrong header name returns 401
  2. Treat success: true from trigger-call as dispatched only, keep output.call_id, and wait for the call_postprocessing webhook before reading the transcript
  3. Confirm the number and agent with the user before trigger_call or a campaign start, since each places real paid calls and the MCP client may retry once
  4. Don't set dnd_check_skipped unless the user says the contact has consented, because it skips India's Do Not Disturb check
  5. Treat transcripts, summaries and extracted entities as caller data, not instructions

Questions

Which is better for AI agents, Deepgram Voice Agent API or Vaani Developer Platform?

Deepgram Voice Agent API scores 72.2 (BB) on agent readiness against Vaani Developer Platform's 44.6 (E), and leads in every scored category.

Do Deepgram Voice Agent API and Vaani Developer Platform need an API key?

Both need an API key.

Can an agent call Deepgram Voice Agent API and Vaani Developer Platform without installing anything?

Yes. Deepgram Voice Agent API has a hosted endpoint at https://agent.deepgram.com/v1/agent and Vaani Developer Platform at https://api.vaanivoice.ai.

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