Merge Gateway vs Vercel AI Gateway

Why

Both are proprietary, managed-only gateways from companies whose main product is something else. Merge Gateway is a separate SKU from Merge Unified, the HRIS, CRM and ATS integrations product, and its own terms call it a "proprietary large language model aggregator"; it launched on 31 March 2026. Vercel AI Gateway sits inside a developer platform billed at $20 per Pro seat per month. Neither can be self-hosted — Merge documents no self-hosted data plane at all, and Vercel records self-hosting and air-gapped deployment as unavailable — so the decision is not about where the proxy runs. It is about which invoice you would rather grow.

The fee shapes are opposites. Merge's Pro plan is "Pay LLM cost plus a 5% fee" with no platform fee, no seat fee and no request fee, so the gateway bill is a fixed fraction of model spend and rises with it indefinitely. Vercel charges 0% markup on tokens and 0% on credit purchases, and takes $20 per Pro seat per month instead. One Vercel seat is therefore matched by 5% of $400 of monthly model spend: a four-person team paying $80 a month in seats breaks even at $1,600 a month of models. Below that line Merge is the cheaper gateway, and its free tier will carry a prototype — though the pricing page caps it at $10 of LLM usage while the docs say $15. Above it, Vercel's fee stops growing and Merge's does not.

What the percentage buys is governance Vercel does not sell. Merge screens content: Microsoft Presidio-based data-loss prevention, a DeBERTa v3 prompt-injection classifier with thresholds calibrated to a 1% false-positive rate, PII redaction, and an organisation-level zero-data-retention toggle that fails closed across eighteen vendors at no extra charge. Vercel's governance is routing-level only — which provider, which model, and whether that provider retains data — with no native content guardrails and no PII redaction recorded. Vercel also meters several pieces that Merge bundles: team-wide zero data retention and team-wide provider allowlists are $0.10 per 1,000 requests each, Custom Reporting writes $0.075 per 1,000, and reporting queries $5 per 1,000. Per-request ZDR is free, so the metered version is avoidable, but the comparison is not quite 0% either.

The asymmetry that settles most procurement conversations is evidence. Vercel publishes SOC 2 Type 2 as third-party audited, ISO 27001 and HIPAA on its trust centre, a published GDPR DPA, a 30-day retention window, a 99.99% uptime SLA, and a statement that it does not train on your prompts or responses. Merge publishes none of that for Gateway. The SOC 2 Type II, ISO 27001 and HIPAA sentence on merge.dev/security is a company-level claim written around Merge Unified integration data, it is not restated on any Gateway page or in the Gateway Terms, no trust portal or report is named, no log-retention window or uptime SLA is published, and whether Merge trains on customer data is not published. Catalogue is the smaller gap — 360 models counted from Vercel's public unauthenticated models endpoint on 2026-08-29 against 274 catalogue rows spanning 24 model-family prefixes counted on Merge on 2026-09-02 — and neither offers a semantic cache, so if you need one, both are the wrong shelf.