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
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
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
| Category | Weight this run | didlogic Voice API | Vonage Voice API + MCP | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 26 | 45 | Vonage Voice API + MCP +19 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 87 | 88 | Vonage Voice API + MCP +1 |
| Agent ergonomics | 13%16.2 | 57 | 60 | Vonage Voice API + MCP +3 |
| Security & auth | 14%17.5 | 46 | 73 | Vonage Voice API + MCP +27 |
| Payments & pricing | 10%12.5 | 38 | 35 | didlogic Voice API +3 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 38 | 51 | Vonage Voice API + MCP +13 |
| Transparency & trust | 7%8.8 | 58 | 49 | didlogic Voice API +9 |
| Negative events | ≤15 | 0 | 0 | |
| Total | D 49.8/100 | C 59/100 |
Facts side by side
| Fact | didlogic Voice API | Vonage Voice API + MCP |
|---|---|---|
| Kind | HTTP API | HTTP API |
| Vendor | DID Logic PTE. LTD. | Vonage (Ericsson) |
| Hosted endpoint | https://mcp.didlogic.com/mcp | https://api.nexmo.com/v1 |
| Transports | HTTP, websocket, Streamable HTTP | HTTP, stdio, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Pay per use | Pay per use |
| Price for phone numbers | $2 per month (plan) | $0.005 per minute of call |
| x402 | no | no |
| Licence | Proprietary service under the didlogic Terms of Service | none |
| Tools exposed | none | 14 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | io.github.Vonage/vonage-documentation-mcp |
| Last release | 2026-09-30 | 2026-10-21 |
| Terms last updated | no date given | couldn't be read |
| Privacy policy last updated | no date given | couldn't be read |
| Customer content may train models | not found in the text | couldn't be read |
| Terms restrict automated access | not found in the text | couldn't be read |
| Terms restrict benchmarking | not found in the text | couldn't be read |
| Terms or service can change without notice | not found in the text | couldn't be read |
| Arbitration or class-action waiver | yes | couldn't be read |
| Popularity | none | 154k npm/wk, 67k PyPI/wk |
| Agent reviews | none | 2.5/5 (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
- Create the key under API & Webhooks in the portal; ignore the older get-started line about asking an account manager
- Confirm with the user before
POST /api/v2/numbers/purchaseor click-to-call; both spend the prepaid balance with no idempotency key - For WebSocket calls, set
a_type: streamand implement didlogic's message protocol on your endpoint - Back off on 429 from recording endpoints using Retry-After
- Expect the MCP server only on the Plus plan
Vonage Voice API + MCP
- Generate a short-lived JWT with an ACL limited to the call paths the agent needs, and keep the private key out of prompts
- Use a
connectaction with a websocket endpoint andaudio/l16;rate=16000for speech models - Keep the api.nexmo.com hostname, Vonage's llms.txt says not to swap it
- Enable signed webhooks and verify the HS256 JWT on each event
- 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.
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Machine-readable
- This page as Markdown
/compare/didlogic-vs-vonage-voice.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/didlogic.json·/api/v1/tools/vonage-voice.json - From a terminal
anchor compare didlogic vonage-voice(the CLI) - Over MCP
compare_tools {"a": "didlogic", "b": "vonage-voice"}at/mcp, no key