Head to head · Phone numbers · October 2026 research run

didlogic Voice API vs Vonage Voice API + MCP

Vonage Voice API + MCP scores 59 (C) on agent readiness against didlogic Voice API's 49.8 (D), and leads in 5 of 7 scored categories. didlogic Voice API leads on transparency & trust. Both do phone numbers.

Best phone calling and voice transport APIs for AI agents · All 105 calling comparisons

Which one, for what

didlogic Voice API D

Best for Teams that need numbers and SIP termination in many countries and a WebSocket bridge to a voice agent.

Ahead on

  • Transparency & trust, 58 against 49

Watch for

No status page or incident history found

Vonage Voice API + MCP C

Best for Voice agents that want 16 or 24 kHz linear PCM over the websocket and per-second billing.

Ahead on

  • Reliability, 45 against 26
  • Security & auth, 73 against 46
  • Maintenance & community, 51 against 38

Also in its favour

  • Runs on your own machine

Watch for

First call needs an application, a private key and a signed JWT

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.

Security & auth Vonage Voice API + MCP +27

didlogic Voice API 46

Revocable bearer keys created in the portal, each with full account access by the vendor's own warning. MCP OAuth mints a separate key per sign-in (18 of 30). SIP accounts can be limited to allowed IPs, with no read-only key and no confirmation on purchases (6 of 20). Caller audio and SMS are untrusted, and no prompt-injection guidance was found (3 of 15). Call detail records, transaction history and risk-check logs through the API, with no audit log of API calls (7 of 15). ISO/IEC 27001:2022 and ISO 9001 certificates from TÜV AUSTRIA Hellas with registration numbers. No security.txt or bug bounty found (12 of 20). 18+6+3+7+12 = 46.

Vonage Voice API + MCP 73

Calls are authorised with an application JWT signed RS256 with the application's private key. Tokens default to 15 minutes and can last from 30 seconds to 24 hours, and an ACL claim can limit a token to named paths and HTTP methods (30). An ACL with GET-only call paths gives an agent a read-only token, though there's no confirmation step for dialling (15 of 20). Calls carry untrusted caller speech. Signed webhooks carry an HS256 JWT with a body hash, and we found no prompt-injection guidance (5 of 15). Call records by GET /v1/calls, and the account-wide Audit API monitors the account through events, as read for the Vonage Messages listing (13 of 15). Per the 2 October reading of www.vonage.com/security/ (bot check since), Vonage holds ISO 27001, PCI-DSS, SOC, HITRUST and CSA STAR across its product lines without saying which cover the Communications APIs. No security.txt, disclosure policy or bug bounty found. OSV lists no advisory for @vonage/server-sdk, vonage or the MCP package. The same page and reading give the Vonage Messages listing 10 (10 of 20). 30 + 15 + 5 + 13 + 10 = 73.

Reliability Vonage Voice API + MCP +19

didlogic Voice API 26

Graded on the hosted API and MCP server with the hosted lines. The footer's network status page carries no components or incidents, and no other status page was found (0). No readable incident history (5). Rate limits are given only for recording lookups (one a second, one lookup a minute) (5 of 15). Those endpoints document 429 with Retry-After and X-RateLimit headers, with no backoff guidance or idempotency elsewhere, including number purchases and click-to-call (6 of 15). The site claims 99.999 per cent voice uptime, but no SLA was found in the Terms (0). The API and click-to-call carry no beta label, while the new buy experience is rolling out gradually (10). 0+5+5+6+0+10 = 26.

Vonage Voice API + MCP 45

Statuspage at vonageapi.statuspage.io with components and history (20). Its history pages, read on 4 November, list Voice entries from 6 August labelled minor or none. Most name one country, number range, region or data centre, such as US East on 13 October and APAC SIP call drops on 11 August, or one function, Text-to-speech on 13 October, so partial and minor. 'Voice Platform Issue' on 19 October was a 'service interruption in Voice traffic' from 15:11 to 16:11 UTC across Voice API, SIP and WebRTC with no region or subset named, read as one major for this listing (10). The 1 October count came from IsDown, a third-party copy that this run bars, and is struck; Vonage's own history has no 20 August eu-4 entry. Per the 2 October check, not re-read on 4 November, no Voice API rate limit on the Voice overview, the OpenAPI document (1.10.0), the API error catalogue or llms.txt (0), and the catalogue's generic throttling error says to retry after waiting, an amount that differs per API, with no Retry-After or backoff detail (5 of 15). No SLA found (0). Voice API is generally available (10). 20 + 10 + 0 + 5 + 0 + 10 = 45.

Maintenance & community Vonage Voice API + MCP +13

didlogic Voice API 38

Release notes dated by month, the newest September 2026 (click-to-call API and WebSocket calls), about 37 to 67 days before this check (20). Entries in August and September and the July self-service API within the 90 days, dated by month only, so fewer than three dated changes can be confirmed (10). Release notes, phone and email support, and a partner programme, with no evidence read of reply times (8 of 15). No official server-side SDK, and the MCP server isn't in the official registry (0). No package to assess (0). 20+10+8+0+0 = 38.

Vonage Voice API + MCP 51

Vonage's SDKs bundle every Vonage API, so their releases count here only where they change voice code, as the Groq speech-to-text and Gemini embedding listings read their SDKs. vonage-java-sdk v9.15.0, tagged on 30 September 2026, added return_cps_on_started to call creation and calls-per-second fields to the started event webhook, 35 days before 4 November (20). In the 90 days from 6 August it is the only SDK release that changes voice code, counted half, so short of three (0). vonage-node-sdk v3.30.0 and v3.30.1, vonage-python-sdk v4.9.0 and v4.9.1, vonage-java-sdk v9.13.0, v9.13.1, v9.14.0 and v9.15.1, vonage-php-sdk-core 4.15.0 and vonage-ruby-sdk 7.36.0 change other APIs, shared client code or formatting. The Python voice package last changed on 20 July (1.5.1, in v4.8.2), and the Node voice package had only version bumps and a lint reformat. The developer changelog index carries only Video entries per the 1 November reading. Closed service with a changelog index and a support site, issue replies not sampled, aligned with the Vonage Messages listing (8 of 15). Official SDKs in six languages (15). CI, lint and PR workflows on the Node SDK, build and mutation-test workflows on the Python SDK (8 of 10). 20 + 0 + 8 + 15 + 8 = 51.

Transparency & trust didlogic Voice API +9

didlogic Voice API 58

Closed service with long, clear terms naming DID Logic PTE. LTD. in Singapore (15 of 30). The privacy policy commits to data minimisation and says call content isn't monitored except for requested recording, but gives no retention periods (12 of 30). No deprecation policy, though the docs explain backward-compatible identifier changes (5 of 20). Twelve points of presence are claimed, with no sub-processor list or data locations found (5 of 20). 15+12+5+5 = 37.

Vonage Voice API + MCP 49

Closed service. The API terms set the contracting entity by region in a schedule we couldn't read (15). Per the 2 October check (www.vonage.com answers a bot check), the privacy policy names Vonage Holdings Corp., and the legal hub links a Data Processing Addendum and HIPAA BAAs sold as an add-on, but no retention periods or sub-processor list were found, read as for the Vonage Messages listing (13 of 30). The Node SDK README marks the Meetings, Number Insight and Number Management APIs as deprecated without dates, SDK methods log deprecation warnings, and the changelog index states no deprecation policy (0 of 20). No sub-processor list or data locations found (0). 15 + 13 + 0 + 0 = 28.

Score by category

CategoryWeight this rundidlogic Voice APIVonage Voice API + MCPEdge
Reliability16%202645Vonage Voice API + MCP +19
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28788Vonage Voice API + MCP +1
Agent ergonomics13%16.25760Vonage Voice API + MCP +3
Security & auth14%17.54673Vonage Voice API + MCP +27
Payments & pricing10%12.53835didlogic Voice API +3
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.83851Vonage Voice API + MCP +13
Transparency & trust7%8.85849didlogic Voice API +9
Negative events≤1500
TotalD 49.8/100C 59/100

Facts side by side

Factdidlogic Voice APIVonage Voice API + MCP
KindHTTP APIHTTP API
VendorDID Logic PTE. LTD.Vonage (Ericsson)
Hosted endpointhttps://mcp.didlogic.com/mcphttps://api.nexmo.com/v1
TransportsHTTP, websocket, Streamable HTTPHTTP, stdio, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingPay per usePay per use
Price for phone numbers$2 per month (plan)$0.005 per minute of call
x402nono
LicenceProprietary service under the didlogic Terms of Servicenone
Tools exposednone14
Read-only variant documentednono
llms.txtyesyes
MCP registrynot listedio.github.Vonage/vonage-documentation-mcp
Last release2026-09-302026-10-21
Terms last updatedno date givencouldn't be read
Privacy policy last updatedno date givencouldn't be read
Customer content may train modelsnot found in the textcouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingnot found in the textcouldn't be read
Terms or service can change without noticenot found in the textcouldn't be read
Arbitration or class-action waiveryescouldn't be read
Popularitynone154k npm/wk, 67k PyPI/wk
Agent reviewsnone2.5/5 (2)

How the scores have moved

Verdicts

didlogic Voice API

didlogic pairs a public OpenAPI file with 53 described operations, published per-minute and number prices and free test credit with WebSocket calls for voice AI and a remote MCP server. There's no status page or SLA, keys carry full account access, and purchases and calls have no idempotency key.

Vonage Voice API + MCP

Websocket audio as 16-bit linear PCM at 8, 16 or 24 kHz, both directions. First call needs an application, a private key and a signed JWT.

Before you call either

didlogic Voice API

  1. Create the key under API & Webhooks in the portal; ignore the older get-started line about asking an account manager
  2. Confirm with the user before POST /api/v2/numbers/purchase or click-to-call; both spend the prepaid balance with no idempotency key
  3. For WebSocket calls, set a_type: stream and implement didlogic's message protocol on your endpoint
  4. Back off on 429 from recording endpoints using Retry-After
  5. Expect the MCP server only on the Plus plan

Vonage Voice API + MCP

  1. Generate a short-lived JWT with an ACL limited to the call paths the agent needs, and keep the private key out of prompts
  2. Use a connect action with a websocket endpoint and audio/l16;rate=16000 for speech models
  3. Keep the api.nexmo.com hostname, Vonage's llms.txt says not to swap it
  4. Enable signed webhooks and verify the HS256 JWT on each event
  5. Expect RFC 7807 errors (type, title, detail, instance) and back off on a throttling error, since no Voice rate limit is published

Questions

Which is better for AI agents, didlogic Voice API or Vonage Voice API + MCP?

Vonage Voice API + MCP scores 59 (C) on agent readiness against didlogic Voice API's 49.8 (D), and leads in 5 of 7 scored categories. didlogic Voice API leads on transparency & trust.

Do didlogic Voice API and Vonage Voice API + MCP need an API key?

Both take an API key or an OAuth sign-in.

Can an agent call didlogic Voice API and Vonage Voice API + MCP without installing anything?

Yes. didlogic Voice API has a hosted endpoint at https://mcp.didlogic.com/mcp and Vonage Voice API + MCP at https://api.nexmo.com/v1.

Other comparisons with didlogic Voice API or Vonage Voice API + MCP

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